diff --git a/rust/tests/banner_test/Cargo.lock b/rust/tests/banner_test/Cargo.lock
new file mode 100644
index 00000000..585ef531
--- /dev/null
+++ b/rust/tests/banner_test/Cargo.lock
@@ -0,0 +1,12 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "banner"
+version = "0.1.0"
+
+[[package]]
+name = "banner_test"
+version = "0.1.0"
+dependencies = [
+ "banner",
+]
diff --git a/rust/tests/banner_test/Cargo.toml b/rust/tests/banner_test/Cargo.toml
new file mode 100644
index 00000000..7f992125
--- /dev/null
+++ b/rust/tests/banner_test/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "banner_test"
+version = "0.1.0"
+authors = ["lee <lee-dasilva@hotmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+banner = { path = "../../../../rust-piscine-solutions/banner"}
diff --git a/rust/tests/banner_test/src/main.rs b/rust/tests/banner_test/src/main.rs
new file mode 100644
index 00000000..c0500785
--- /dev/null
+++ b/rust/tests/banner_test/src/main.rs
@@ -0,0 +1,88 @@
+use std::collections::HashMap;
+use banner::*;
+
+fn main() {
+    let mut handler = FlagsHandler { flags: HashMap::new() };
+
+    let d = Flag::opt_flag("division", "divides the values, formula (a / b)");
+    let r = Flag::opt_flag(
+        "remainder",
+        "remainder of the division between two values, formula (a % b)",
+    );
+
+    handler.add_flag((d.short_hand, d.long_hand), div);
+    handler.add_flag((r.short_hand, r.long_hand), rem);
+
+    println!("{:?}", handler.exec_func(("-d".to_string(), "--division".to_string()), &["1.0", "2.0"]));
+    // output: "0.5"
+
+    println!("{:?}",handler.exec_func(("-r".to_string(), "--remainder".to_string()), &["2.0", "2.0"]));
+    // output: "0.0"
+    
+    println!("{:?}",handler.exec_func(("-d".to_string(), "--division".to_string()), &["a", "2.0"]));
+    // output: "invalid float literal"
+    
+    println!("{:?}",handler.exec_func(("-r".to_string(), "--remainder".to_string()), &["2.0", "fd"]));
+    // output: "invalid float literal"
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn init() -> FlagsHandler {
+        let d = Flag::opt_flag("division", "divides two numbers");
+        let r = Flag::opt_flag(
+            "remainder",
+            "gives the remainder of the division between two numbers",
+        );
+        let mut handler = FlagsHandler { flags: HashMap::new() };
+
+        handler.add_flag((d.short_hand, d.long_hand), div);
+        handler.add_flag((r.short_hand, r.long_hand), rem);
+        return handler;
+    }
+
+    #[test]
+    fn ok_test() {
+        let mut handler = init();
+        assert_eq!(
+            handler.exec_func(("-d".to_string(), "--division".to_string()), &["1.0", "2.0"]),
+            "0.5"
+        );
+        assert_eq!(
+            handler.exec_func(("-r".to_string(), "--remainder".to_string()), &["2.0", "2.0"]),
+            "0"
+        );
+        assert_eq!(
+            handler.exec_func(("-d".to_string(), "--division".to_string()), &["12.323", "212.32"]),
+            "0.05803975"
+        );
+        assert_eq!(
+            handler.exec_func(("-r".to_string(), "--remainder".to_string()), &["12.323", "212.32"]),
+            "12.323"
+        );
+    }
+
+    #[test]
+    fn error_test() {
+        let mut handler = init();
+        assert_eq!(
+            handler.exec_func(("-d".to_string(), "--division".to_string()), &["a", "2.0"]),
+            "invalid float literal"
+        );
+        assert_eq!(
+            handler.exec_func(("-r".to_string(), "--remainder".to_string()), &["2.0", "f"]),
+            "invalid float literal"
+        );
+        assert_eq!(
+            handler.exec_func(("-d".to_string(), "--division".to_string()), &["1.0", "0.0"]),
+            "inf"
+        );
+        assert_eq!(
+            handler.exec_func(("-r".to_string(), "--remainder".to_string()), &["2.0", "0.0"]),
+            "NaN"
+        );
+    }
+}
+
diff --git a/rust/tests/borrow_box_test/Cargo.lock b/rust/tests/borrow_box_test/Cargo.lock
new file mode 100644
index 00000000..c1ff1ef0
--- /dev/null
+++ b/rust/tests/borrow_box_test/Cargo.lock
@@ -0,0 +1,12 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "borrow_box"
+version = "0.1.0"
+
+[[package]]
+name = "borrow_box_test"
+version = "0.1.0"
+dependencies = [
+ "borrow_box",
+]
diff --git a/rust/tests/borrow_box_test/Cargo.toml b/rust/tests/borrow_box_test/Cargo.toml
new file mode 100644
index 00000000..9d448ad9
--- /dev/null
+++ b/rust/tests/borrow_box_test/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "borrow_box_test"
+version = "0.1.0"
+authors = ["lee <lee-dasilva@hotmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+borrow_box = { path = "../../../../rust-piscine-solutions/borrow_box"}
diff --git a/rust/tests/borrow_box_test/src/main.rs b/rust/tests/borrow_box_test/src/main.rs
new file mode 100644
index 00000000..beed0141
--- /dev/null
+++ b/rust/tests/borrow_box_test/src/main.rs
@@ -0,0 +1,91 @@
+use borrow_box::*;
+
+fn main() {
+    let mut game = Game::new(0, String::from("Joao"), String::from("Susana"), 5);
+    println!("{:?}", game.read_winner());
+    // output : ("Same score! tied", 0)
+
+    game.update_score(String::from("Joao"));
+    game.update_score(String::from("Joao"));
+    game.update_score(String::from("Susana"));
+    game.update_score(String::from("Susana"));
+    println!("{:?}", game.read_winner());
+    // output : ("Same score! tied", 2)
+
+    game.update_score(String::from("Joao"));
+    // this one will not count because it already 5 games played, the nbr_of_games
+    game.update_score(String::from("Susana"));
+    
+    println!("{:?}", game.read_winner());
+    // output : ("Joao", 3)
+
+    println!("{:?}", game.delete());
+    // output : "game deleted: id -> 0"
+
+    // game.read_winner();
+    // this will give error
+    // because the game was dropped, no longer exists on the heap
+}
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn create_games() -> Vec<Box<Game>> {
+        vec![
+            Game::new(0, String::from("player1"), String::from("player2"), 1),
+            Game::new(1, String::from("Alice"), String::from("Mark"), 3),
+            Game::new(2, String::from("Jack"), String::from("Miller"), 5)
+        ]
+    }
+
+    #[test]
+    fn test_create() {
+        let games = create_games();
+        assert_eq!(*games[0], Game {id: 0, p1: (String::from("player1"), 0), p2: (String::from("player2"), 0), nbr_of_games: 1});
+        assert_eq!(*games[1], Game {id: 1, p1: (String::from("Alice"), 0), p2: (String::from("Mark"), 0), nbr_of_games: 3});
+        assert_eq!(*games[2], Game {id: 2, p1: (String::from("Jack"), 0), p2: (String::from("Miller"), 0), nbr_of_games: 5});
+    }
+
+    #[test]
+    fn test_update_and_read() {
+        let mut games = create_games();
+        games[0].update_score(String::from("player1"));
+        assert_eq!(games[0].read_winner(), (String::from("player1"), 1));
+
+        games[0].update_score(String::from("player2"));
+        // this will stay the same because the nbr_of_games is 1 so if one
+        // of the players wins just once it will no longer increment the score
+        assert_eq!(games[0].read_winner(), (String::from("player1"), 1));
+
+        games[2].update_score(String::from("Jack"));
+        games[2].update_score(String::from("Jack"));
+        games[2].update_score(String::from("Miller"));
+        games[2].update_score(String::from("Miller"));
+        // tie between players
+        assert_eq!(games[2].read_winner(), (String::from("Same score! tied"), 2));
+
+        games[2].update_score(String::from("Jack"));
+        assert_eq!(games[2].read_winner(), (String::from("Jack"), 3));
+    }
+
+    #[test]
+    fn test_delete() {
+        let game = Game::new(0, String::from("Alice"), String::from("Mark"), 3);
+        let game1 = Game::new(23, String::from("Jack"), String::from("Miller"), 1);
+
+        assert_eq!(game.delete(), String::from("game deleted: id -> 0"));
+        assert_eq!(game1.delete(), String::from("game deleted: id -> 23"));
+    }
+
+    // #[test]
+    // #[should_panic]
+    // fn test_delete_ownership() {
+    //     let game = new(0, String::from("Alice"), String::from("Mark"), 3);
+    //     {
+    //         let a = &game;
+    //         // error! cant destroy boxed while the inner value is borrowed later in scope
+    //         delete(game);
+    //         read_winner(&a);
+    //     }
+    // }
+}
diff --git a/rust/tests/box_it_test/Cargo.lock b/rust/tests/box_it_test/Cargo.lock
new file mode 100644
index 00000000..f322a385
--- /dev/null
+++ b/rust/tests/box_it_test/Cargo.lock
@@ -0,0 +1,12 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "box_it"
+version = "0.1.0"
+
+[[package]]
+name = "box_it_test"
+version = "0.1.0"
+dependencies = [
+ "box_it",
+]
diff --git a/rust/tests/box_it_test/Cargo.toml b/rust/tests/box_it_test/Cargo.toml
new file mode 100644
index 00000000..98d33050
--- /dev/null
+++ b/rust/tests/box_it_test/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "box_it_test"
+version = "0.1.0"
+authors = ["lee <lee-dasilva@hotmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+box_it = { path = "../../../../rust-piscine-solutions/box_it"}
diff --git a/rust/tests/box_it_test/src/main.rs b/rust/tests/box_it_test/src/main.rs
new file mode 100644
index 00000000..c69033f8
--- /dev/null
+++ b/rust/tests/box_it_test/src/main.rs
@@ -0,0 +1,56 @@
+use box_it::*;
+
+fn main() {
+    let new_str = String::from("5.5k 8.9k 32");
+
+    // creating a variable and we save it in the Heap
+    let a_h = transform_and_save_on_heap(new_str);
+    println!("Box value : {:?}", &a_h);
+    println!("size occupied in the stack : {:?} bytes", (std::mem::size_of_val(&a_h)));
+    
+    let a_b_v = take_value_ownership(a_h);
+    println!("value : {:?}", &a_b_v);
+    println!("size occupied in the stack : {:?} bytes", (std::mem::size_of_val(&a_b_v)));
+    // whenever the box, in this case "a_h", goes out of scope it will be deallocated, freed
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::mem;
+
+    #[test]
+    fn test_transform() {
+        let new_str = String::from("5.5k 8.9k 32");
+        let new_str_1 = String::from("6.8k 13.5k");
+        let new_str_2 = String::from("20.3k 3.8k 7.7k 992");
+
+        let a = transform_and_save_on_heap(new_str);
+        let b = transform_and_save_on_heap(new_str_1);
+        let c = transform_and_save_on_heap(new_str_2);
+
+        assert_eq!(a, Box::new(vec![5500, 8900, 32]));
+        assert_eq!(b, Box::new(vec![6800, 13500]));
+        assert_eq!(c, Box::new(vec![20300, 3800, 7700, 992]));
+        assert_eq!(mem::size_of_val(&a), 8);
+        assert_eq!(mem::size_of_val(&b), 8);
+        assert_eq!(mem::size_of_val(&c), 8);
+    }
+
+    #[test]
+    fn test_take_value_from_box() {
+        let new_str = String::from("5.5k 8.9k 32");
+        let new_str_1 = String::from("6.8k 13.5k");
+        let new_str_2 = String::from("20.3k 3.8k 7.7k 992");
+        let a = take_value_ownership(transform_and_save_on_heap(new_str));
+        let b = take_value_ownership(transform_and_save_on_heap(new_str_1));
+        let c = take_value_ownership(transform_and_save_on_heap(new_str_2));
+
+        assert_eq!(a, vec![5500, 8900, 32]);
+        assert_eq!(b, vec![6800, 13500]);
+        assert_eq!(c, vec![20300, 3800, 7700, 992]);
+        assert_eq!(mem::size_of_val(&a), 24);
+        assert_eq!(mem::size_of_val(&b), 24);
+        assert_eq!(mem::size_of_val(&c), 24);
+    }
+}
diff --git a/rust/tests/box_recursion_test/Cargo.lock b/rust/tests/box_recursion_test/Cargo.lock
new file mode 100644
index 00000000..1e77a0dc
--- /dev/null
+++ b/rust/tests/box_recursion_test/Cargo.lock
@@ -0,0 +1,12 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "box_recursion"
+version = "0.1.0"
+
+[[package]]
+name = "box_recursion_test"
+version = "0.1.0"
+dependencies = [
+ "box_recursion",
+]
diff --git a/rust/tests/box_recursion_test/Cargo.toml b/rust/tests/box_recursion_test/Cargo.toml
new file mode 100644
index 00000000..db29730c
--- /dev/null
+++ b/rust/tests/box_recursion_test/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "box_recursion_test"
+version = "0.1.0"
+authors = ["lee <lee-dasilva@hotmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+box_recursion = { path = "../../../../rust-piscine-solutions/box_recursion"}
diff --git a/rust/tests/box_recursion_test/src/main.rs b/rust/tests/box_recursion_test/src/main.rs
new file mode 100644
index 00000000..6de2aa07
--- /dev/null
+++ b/rust/tests/box_recursion_test/src/main.rs
@@ -0,0 +1,98 @@
+use box_recursion::*;
+
+fn main() {
+    let mut list = WorkEnvironment::new();
+    list.add_worker(String::from("CEO"), String::from("Marie"));
+    list.add_worker(String::from("Manager"), String::from("Monica"));
+    list.add_worker(String::from("Normal Worker"), String::from("Ana"));
+    list.add_worker(String::from("Normal Worker"), String::from("Alice"));
+    println!("{:?}", list);
+
+    println!("{:?}", list.search_worker());
+
+    list.remove_worker();
+    list.remove_worker();
+    list.remove_worker();
+    list.remove_worker();
+    println!("{:?}", list);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_new() {
+        let list = WorkEnvironment::new();
+        assert!(list.grade.is_none());
+    }
+
+    #[test]
+    fn test_one_worker() {
+        let mut list = WorkEnvironment::new();
+        list.add_worker(String::from("CEO"), String::from("Marie"));
+        list.remove_worker();
+        assert!(list.grade.is_none());
+    }
+
+    #[test]
+    fn test_two_workers() {
+        let mut list = WorkEnvironment::new();
+        list.add_worker(String::from("CEO"), String::from("Marie"));
+        list.add_worker(String::from("Manager"), String::from("Monica"));
+        list.remove_worker();
+
+        assert_eq!(list.grade.as_ref().unwrap().worker_type, "CEO");
+        assert_eq!(list.grade.as_ref().unwrap().worker_name, "Marie");
+    }
+
+    #[test]
+    fn test_more_workers() {
+        let mut list = WorkEnvironment::new();
+        list.add_worker(String::from("CEO"), String::from("Marie"));
+        list.add_worker(String::from("Manager"), String::from("Monica"));
+        list.add_worker(String::from("Normal Worker"), String::from("Ana"));
+        list.add_worker(String::from("Normal Worker"), String::from("Alice"));
+        list.remove_worker();
+
+        assert_eq!(list.grade.as_ref().unwrap().worker_type, "Normal Worker");
+        assert_eq!(list.grade.as_ref().unwrap().worker_name, "Ana");
+
+        list.remove_worker();
+        list.remove_worker();
+        assert_eq!(list.grade.as_ref().unwrap().worker_type, "CEO");
+        assert_eq!(list.grade.as_ref().unwrap().worker_name, "Marie");
+    }
+
+    #[test]
+    fn test_search() {
+        let mut list = WorkEnvironment::new();
+        list.add_worker(String::from("CEO"), String::from("Marie"));
+        list.add_worker(String::from("Manager"), String::from("Monica"));
+        list.add_worker(String::from("Normal Worker"), String::from("Ana"));
+        list.add_worker(String::from("Normal Worker"), String::from("Alice"));
+
+        assert_eq!(
+            list.search_worker().unwrap(),
+            (String::from("Alice"), String::from("Normal Worker"))
+        );
+
+        list.remove_worker();
+        assert_eq!(
+            list.search_worker().unwrap(),
+            (String::from("Ana"), String::from("Normal Worker"))
+        );
+
+        list.remove_worker();
+        assert_eq!(
+            list.search_worker().unwrap(),
+            (String::from("Monica"), String::from("Manager"))
+        );
+
+        list.remove_worker();
+        assert_eq!(
+            list.search_worker().unwrap(),
+            (String::from("Marie"), String::from("CEO"))
+        );
+    }
+}
diff --git a/rust/tests/boxing_todo_test/Cargo.lock b/rust/tests/boxing_todo_test/Cargo.lock
new file mode 100644
index 00000000..7c71d7d5
--- /dev/null
+++ b/rust/tests/boxing_todo_test/Cargo.lock
@@ -0,0 +1,96 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "boxing_todo"
+version = "0.1.0"
+dependencies = [
+ "serde",
+ "serde_json",
+]
+
+[[package]]
+name = "boxing_todo_test"
+version = "0.1.0"
+dependencies = [
+ "boxing_todo",
+ "serde",
+ "serde_json",
+]
+
+[[package]]
+name = "itoa"
+version = "0.4.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dd25036021b0de88a0aff6b850051563c6516d0bf53f8638938edbb9de732736"
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e0704ee1a7e00d7bb417d0770ea303c1bccbabf0ef1667dae92b5967f5f8a71"
+dependencies = [
+ "unicode-xid",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "991431c3519a3f36861882da93630ce66b52918dcf1b8e2fd66b397fc96f28df"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "ryu"
+version = "1.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "71d301d4193d031abdd79ff7e3dd721168a9572ef3fe51a1517aba235bd8f86e"
+
+[[package]]
+name = "serde"
+version = "1.0.118"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "06c64263859d87aa2eb554587e2d23183398d617427327cf2b3d0ed8c69e4800"
+dependencies = [
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.118"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c84d3526699cd55261af4b941e4e725444df67aa4f9e6a3564f18030d12672df"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "serde_json"
+version = "1.0.60"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1500e84d27fe482ed1dc791a56eddc2f230046a040fa908c08bda1d9fb615779"
+dependencies = [
+ "itoa",
+ "ryu",
+ "serde",
+]
+
+[[package]]
+name = "syn"
+version = "1.0.56"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a9802ddde94170d186eeee5005b798d9c159fa970403f1be19976d0cfb939b72"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-xid",
+]
+
+[[package]]
+name = "unicode-xid"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f7fe0bb3479651439c9112f72b6c505038574c9fbb575ed1bf3b797fa39dd564"
diff --git a/rust/tests/boxing_todo_test/Cargo.toml b/rust/tests/boxing_todo_test/Cargo.toml
new file mode 100644
index 00000000..cd7019e9
--- /dev/null
+++ b/rust/tests/boxing_todo_test/Cargo.toml
@@ -0,0 +1,12 @@
+[package]
+name = "boxing_todo_test"
+version = "0.1.0"
+authors = ["lee <lee-dasilva@hotmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+boxing_todo = { path = "../../../../rust-piscine-solutions/boxing_todo"}
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
diff --git a/rust/tests/boxing_todo_test/src/main.rs b/rust/tests/boxing_todo_test/src/main.rs
new file mode 100644
index 00000000..394a074f
--- /dev/null
+++ b/rust/tests/boxing_todo_test/src/main.rs
@@ -0,0 +1,99 @@
+use boxing_todo::*;
+
+// Note that you can create some todo list your self to test it, but you can find the JSON files that
+// are being tested [here](https://github.com/01-edu/public/blob/master/subjects/boxing_todo)
+fn main() {
+    let todos = TodoList::get_todo("todo.json");
+    match todos {
+        Ok(list) => println!("{:?}", list),
+        Err(e) => {
+            println!("{}{:?}", e.description(), e.cause());
+        }
+    }
+
+    let todos = TodoList::get_todo("malforned_object.json");
+    match todos {
+        Ok(list) => println!("{:?}", list),
+        Err(e) => {
+            println!("{}{:?}", e.description(), e.cause().unwrap());
+        }
+    }
+
+    let todos = TodoList::get_todo("permission_err.json");
+    match todos {
+        Ok(list) => println!("{:?}", list),
+        Err(e) => {
+            println!("{}{:?}", e.description(), e.cause().unwrap());
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::fs::File;
+    use std::fs;
+
+    fn new_todo(s: String, v: Vec<Task>) -> TodoList {
+        TodoList { title: s, tasks: v }
+    }
+    fn run(s: &TodoList, f: &str) -> Result<TodoList, Box<dyn Error>> {
+        serde_json::to_writer(&File::create(f)?, s)?;
+        let result = TodoList::get_todo(f);
+		fs::remove_file(f)?;
+        return result;
+    }
+
+    #[test]
+    fn test_good_todo() {
+        let file_name = "todo.json";
+        let good_struct = new_todo(
+            String::from("todo list for something"),
+            vec![
+                Task { id: 0, description: "do this".to_string(), level: 0 },
+                Task { id: 1, description: "do that".to_string(), level: 5 },
+            ],
+        );
+        let result = run(&good_struct, file_name).unwrap();
+
+        assert_eq!(result.title, good_struct.title);
+        assert_eq!(&result.tasks, &good_struct.tasks);
+    }
+
+    #[test]
+    fn test_empty_tasks() {
+        let file_name = "empty_tasks.json";
+        let result = run(&new_todo(String::from("empty tasks"), vec![]), file_name).unwrap_err();
+
+        assert_eq!(result.to_string(), "Failed to parses todo");
+        assert_eq!(result.description(), "Todo List parse failed: ");
+        assert!(!result.cause().is_some());
+    }
+    #[test]
+    fn test_read() {
+        let result = TodoList::get_todo("no_file.json").unwrap_err();
+
+        assert_eq!(result.to_string(), "Failed to read todo file");
+        assert_eq!(result.description(), "Todo List read failed: ");
+    }
+
+    #[test]
+    #[should_panic(expected = "Malformed(Error(\"missing field `title`\", line: 1, column: 2))")]
+    fn test_malformed_json() {
+        #[derive(Serialize, Deserialize)]
+        struct Mal {};
+        let file_name = "malformed.json";
+        let malformed: Mal = serde_json::from_str(r#"{}"#).unwrap();
+        serde_json::to_writer(&File::create(file_name).unwrap(), &malformed).unwrap();
+        let result = TodoList::get_todo(file_name);
+        fs::remove_file(file_name).unwrap();
+
+        result.unwrap_or_else(|e| panic!("{:?}", e));
+    }
+
+    #[test]
+    #[should_panic(expected = "ReadErr { child_err: Os { code: 2, kind: NotFound, message: \"No such file or directory\" } }")]
+    fn test_read_error() {
+        TodoList::get_todo("no_file.json").unwrap_or_else(|e| panic!("{:?}", e));
+    }
+}
diff --git a/rust/tests/cipher_test/Cargo.lock b/rust/tests/cipher_test/Cargo.lock
new file mode 100644
index 00000000..fbb752c6
--- /dev/null
+++ b/rust/tests/cipher_test/Cargo.lock
@@ -0,0 +1,12 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "cipher"
+version = "0.1.0"
+
+[[package]]
+name = "cipher_test"
+version = "0.1.0"
+dependencies = [
+ "cipher",
+]
diff --git a/rust/tests/cipher_test/Cargo.toml b/rust/tests/cipher_test/Cargo.toml
new file mode 100644
index 00000000..3d3c9f42
--- /dev/null
+++ b/rust/tests/cipher_test/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "cipher_test"
+version = "0.1.0"
+authors = ["lee <lee-dasilva@hotmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+cipher = { path = "../../../../rust-piscine-solutions/cipher"}
diff --git a/rust/tests/cipher_test/src/main.rs b/rust/tests/cipher_test/src/main.rs
new file mode 100644
index 00000000..186fe157
--- /dev/null
+++ b/rust/tests/cipher_test/src/main.rs
@@ -0,0 +1,24 @@
+use cipher::*;
+
+fn main() {
+    println!("{:?}", cipher("1Hello 2world!", "1Svool 2dliow!"));
+    println!("{:?}", cipher("1Hello 2world!", "svool"));
+    println!("{:?}", cipher("", "svool"));
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_cipher() {
+        assert_eq!(cipher("1Hello 2world!", "1Svool 2dliow!"), Some(Ok(true)));
+        assert_eq!(cipher("", "1Svool 2dliow!"), None);
+        assert_eq!(cipher("1Hello 2world!", ""), None);
+        assert_eq!(cipher("1Hello 2world!", "1svool 2dliow!"), Some(Err(CipherError { validation: false, expected: String::from("1Svool 2dliow!") })));
+        assert_eq!(cipher("asdasd", "zhwzhw"), Some(Ok(true)));
+        assert_eq!(cipher("asdasd", "lkdas"), Some(Err(CipherError { validation: false, expected: String::from("zhwzhw") })));
+        assert_eq!(cipher("3(/&%fsd 32das", "3(/&%uhw 32wzh"), Some(Ok(true)));
+        assert_eq!(cipher("3(/&%sd 32das", "3(/&%uhw 32wzh"), Some(Err(CipherError { validation: false, expected: String::from("3(/&%hw 32wzh") })));
+    }
+}
\ No newline at end of file
diff --git a/rust/tests/drop_the_thread_test/Cargo.lock b/rust/tests/drop_the_thread_test/Cargo.lock
new file mode 100644
index 00000000..2bd03a8e
--- /dev/null
+++ b/rust/tests/drop_the_thread_test/Cargo.lock
@@ -0,0 +1,12 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "drop_the_thread"
+version = "0.1.0"
+
+[[package]]
+name = "drop_the_thread_test"
+version = "0.1.0"
+dependencies = [
+ "drop_the_thread",
+]
diff --git a/rust/tests/drop_the_thread_test/Cargo.toml b/rust/tests/drop_the_thread_test/Cargo.toml
new file mode 100644
index 00000000..875b1907
--- /dev/null
+++ b/rust/tests/drop_the_thread_test/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "drop_the_thread_test"
+version = "0.1.0"
+authors = ["lee <lee-dasilva@hotmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+drop_the_thread = { path = "../../../../rust-piscine-solutions/drop_the_thread"}
diff --git a/rust/tests/drop_the_thread_test/src/main.rs b/rust/tests/drop_the_thread_test/src/main.rs
new file mode 100644
index 00000000..f2882549
--- /dev/null
+++ b/rust/tests/drop_the_thread_test/src/main.rs
@@ -0,0 +1,87 @@
+use drop_the_thread::*;
+use std::rc::Rc;
+
+fn main() {
+    let worker = Workers::new();
+    let (id, thread) = worker.new_worker(String::from("command"));
+    let (id1, thread1) = worker.new_worker(String::from("command1"));
+
+    thread.skill();
+
+    println!("{:?}", (worker.is_dropped(id), id, &worker.drops));
+    // output: (true, 0, Cell { value: 1 })
+
+    thread1.skill();
+    println!("{:?}", (worker.is_dropped(id1), id1, &worker.drops));
+    // output: (true, 1, Cell { value: 2 })
+
+    let (id2, thread2) = worker.new_worker(String::from("command2"));
+    let thread2 = Rc::new(thread2);
+    let thread2_clone = thread2.clone();
+
+    // thread2_clone.skill();
+    drop(thread2_clone);
+
+    println!("{:?}", (worker.is_dropped(id2), id2, &worker.drops, Rc::strong_count(&thread2)));
+    // (false, 2, Cell { value: 2 }, 1)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::rc::Rc;
+
+    #[test]
+    fn test_is_dropped_and_drops() {
+        let worker = Workers::new();
+        let (pid, thread) = worker.new_worker(String::from("gnome-shell"));
+        let (pid0, thread0) = worker.new_worker(String::from("i3"));
+        let (pid1, thread1) = worker.new_worker(String::from("shell"));
+        let (pid2, thread2) = worker.new_worker(String::from("spotify"));
+
+       thread.skill();
+       assert_eq!(worker.drops.get(), 1_usize);
+       thread0.skill();
+
+       assert!(worker.is_dropped(pid), "{} should have been dropped", pid);
+       assert!(worker.is_dropped(pid0), "{} should have been dropped", pid0);
+       assert!(!worker.is_dropped(pid1), "{} should not have been dropped", pid1);
+       assert!(!worker.is_dropped(pid2), "{} should not have been dropped", pid2);
+
+       assert_eq!(worker.drops.get(), 2_usize);
+
+       thread1.skill();
+       thread2.skill();
+
+       assert_eq!(worker.drops.get(), 4_usize);
+    }
+
+    #[test]
+    fn test_using_rc() {
+      // will create a new reference to the thread
+      // this will test the following
+      // if we drop the cloned value the RC will decrease
+      // but the thread will not be dropped! 
+      let worker = Workers::new();
+      let (_, thread) = worker.new_worker(String::from("Xorg"));
+      let thread = Rc::new(thread);
+      let thread_clone = thread.clone();
+
+      assert_eq!(Rc::strong_count(&thread), 2);
+
+      drop(thread_clone);
+
+      assert_eq!(Rc::strong_count(&thread), 1);
+    }
+
+    #[test]
+    #[should_panic(expected = "0 is already dropped")]
+    fn test_drop_same_thread() {
+        // test if we drop the same thread after it was already been dropped
+        let worker = Workers::new();
+        let (pid, thread) = worker.new_worker(String::from("gsd-rfkill"));
+        let thread_clone = thread.clone();
+        thread.skill();
+        thread_clone.skill();
+    }
+}
diff --git a/rust/tests/error_type_test/Cargo.lock b/rust/tests/error_type_test/Cargo.lock
new file mode 100644
index 00000000..21a3eb4f
--- /dev/null
+++ b/rust/tests/error_type_test/Cargo.lock
@@ -0,0 +1,98 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "autocfg"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
+
+[[package]]
+name = "chrono"
+version = "0.4.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "670ad68c9088c2a963aaa298cb369688cf3f9465ce5e2d4ca10e6e0098a1ce73"
+dependencies = [
+ "libc",
+ "num-integer",
+ "num-traits",
+ "time",
+ "winapi",
+]
+
+[[package]]
+name = "error_type"
+version = "0.1.0"
+dependencies = [
+ "chrono",
+]
+
+[[package]]
+name = "error_type_test"
+version = "0.1.0"
+dependencies = [
+ "error_type",
+]
+
+[[package]]
+name = "libc"
+version = "0.2.81"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1482821306169ec4d07f6aca392a4681f66c75c9918aa49641a2595db64053cb"
+
+[[package]]
+name = "num-integer"
+version = "0.1.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d2cc698a63b549a70bc047073d2949cce27cd1c7b0a4a862d08a8031bc2801db"
+dependencies = [
+ "autocfg",
+ "num-traits",
+]
+
+[[package]]
+name = "num-traits"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9a64b1ec5cda2586e284722486d802acf1f7dbdc623e2bfc57e65ca1cd099290"
+dependencies = [
+ "autocfg",
+]
+
+[[package]]
+name = "time"
+version = "0.1.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6db9e6914ab8b1ae1c260a4ae7a49b6c5611b40328a735b21862567685e73255"
+dependencies = [
+ "libc",
+ "wasi",
+ "winapi",
+]
+
+[[package]]
+name = "wasi"
+version = "0.10.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1a143597ca7c7793eff794def352d41792a93c481eb1042423ff7ff72ba2c31f"
+
+[[package]]
+name = "winapi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
diff --git a/rust/tests/error_type_test/Cargo.toml b/rust/tests/error_type_test/Cargo.toml
new file mode 100644
index 00000000..dd5627fa
--- /dev/null
+++ b/rust/tests/error_type_test/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "error_type_test"
+version = "0.1.0"
+authors = ["lee <lee-dasilva@hotmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+error_type = { path = "../../../../rust-piscine-solutions/error_type"}
diff --git a/rust/tests/error_type_test/src/main.rs b/rust/tests/error_type_test/src/main.rs
new file mode 100644
index 00000000..6685e5a2
--- /dev/null
+++ b/rust/tests/error_type_test/src/main.rs
@@ -0,0 +1,136 @@
+use error_type::*;
+
+#[allow(dead_code)]
+fn create_date(date: &str) -> NaiveDate {
+    NaiveDate::parse_from_str(date, "%Y-%m-%d").unwrap()
+}
+
+fn main() {
+    let mut form_output = Form::new(
+        String::from("Lee"),
+        String::from("Silva"),
+        create_date("2015-09-05"),
+        SexType::Male,
+        String::from("Africa"),
+        String::from("qwqwsa1dty_"));
+
+    println!("{:?}", form_output);
+    println!("{:?}", form_output.validate().unwrap());
+
+    form_output.first_name = String::from("");
+    println!("{:?}", form_output.validate().unwrap_err());
+
+    form_output.first_name = String::from("as");
+    form_output.password = String::from("dty_1");
+    println!("{:?}", form_output.validate().unwrap_err());
+
+    form_output.password = String::from("asdasASd(_");
+    println!("{:?}", form_output.validate().unwrap_err());
+
+    form_output.password = String::from("asdasASd123SA");
+    println!("{:?}", form_output.validate().unwrap_err());
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[derive(Debug)]
+    struct TestForm<'a> {
+        form: Form,
+        validation: Result<Vec<&'a str>, FErr>
+    }
+
+    impl <'a> TestForm<'_> {
+        // all test cases
+        fn new() -> Vec<TestForm<'a>> {
+            vec![
+                TestForm {
+                    form : Form::new(
+                    String::from("Katy"),
+                    String::from("Silva"),
+                    create_date("2015-09-05"),
+                    SexType::Female,
+                    String::from("Africa"),
+                    String::from("qwTw12&%$3sa1dty_")),
+                    validation: Ok(vec!["Valid first name", "Valid password"]),
+                },
+                TestForm {
+                    form : Form::new(
+                    String::from(""),
+                    String::from("Bear"),
+                    create_date("2015-09-05"),
+                    SexType::Male,
+                    String::from("Africa"),
+                    String::from("qwTw12&%$3sa1dty_")),
+                    validation: Err(FErr {
+                        form_values: (String::from("first_name"),
+                        String::from("")),
+                        date: Utc::now().format("%Y-%m-%d %H:%M:%S").to_string(),
+                        err: String::from("No user name")}),
+                },
+                TestForm {
+                    form : Form::new(
+                    String::from("Someone"),
+                    String::from("Bear"),
+                    create_date("2015-09-05"),
+                    SexType::Male,
+                    String::from("Africa"),
+                    String::from("12345")),
+                    validation: Err(FErr {
+                        form_values: (String::from("password"), String::from("12345")),
+                        date: Utc::now().format("%Y-%m-%d %H:%M:%S").to_string(),
+                        err: String::from("At least 8 characters") }),
+                },
+                TestForm {
+                    form : Form::new(
+                    String::from("Someone"),
+                    String::from("Bear"),
+                    create_date("2015-09-05"),
+                    SexType::Male,
+                    String::from("Africa"),
+                    String::from("sdASDsrW")),
+                    validation: Err(FErr {
+                        form_values: (String::from("password"), String::from("sdASDsrW")),
+                        date: Utc::now().format("%Y-%m-%d %H:%M:%S").to_string(),
+                        err: String::from("Combination of different ASCII character types (numbers, letters and none alphanumeric characters)") }),
+                },
+                TestForm {
+                    form : Form::new(
+                    String::from("Someone"),
+                    String::from("Bear"),
+                    create_date("2015-09-05"),
+                    SexType::Female,
+                    String::from("Africa"),
+                    String::from("dsGE1SAD213")),
+                    validation: Err(FErr {
+                        form_values: (String::from("password"), String::from("dsGE1SAD213")),
+                        date: Utc::now().format("%Y-%m-%d %H:%M:%S").to_string(),
+                        err: String::from("Combination of different ASCII character types (numbers, letters and none alphanumeric characters)") }),
+                },
+                TestForm {
+                    form : Form::new(
+                    String::from("Someone"),
+                    String::from("Bear"),
+                    create_date("2015-09-05"),
+                    SexType::Female,
+                    String::from("Africa"),
+                    String::from("dsaSD&%DF!?=")),
+                    validation: Err(FErr {
+                        form_values: (String::from("password"), String::from("dsaSD&%DF!?=")),
+                        date: Utc::now().format("%Y-%m-%d %H:%M:%S").to_string(),
+                        err: String::from("Combination of different ASCII character types (numbers, letters and none alphanumeric characters)") }),
+                }
+            ]
+        }
+    }
+
+    #[test]
+    fn test_error_type() {
+        let form_cases = TestForm::new();
+
+        for v in form_cases {
+            assert_eq!(v.form.validate(), v.validation);
+        }
+    }
+}
\ No newline at end of file
diff --git a/rust/tests/handling_test/Cargo.lock b/rust/tests/handling_test/Cargo.lock
new file mode 100644
index 00000000..a780a192
--- /dev/null
+++ b/rust/tests/handling_test/Cargo.lock
@@ -0,0 +1,12 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "handling"
+version = "0.1.0"
+
+[[package]]
+name = "handling_test"
+version = "0.1.0"
+dependencies = [
+ "handling",
+]
diff --git a/rust/tests/handling_test/Cargo.toml b/rust/tests/handling_test/Cargo.toml
new file mode 100644
index 00000000..0e66dff7
--- /dev/null
+++ b/rust/tests/handling_test/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "handling_test"
+version = "0.1.0"
+authors = ["lee <lee-dasilva@hotmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+handling = { path = "../../../../rust-piscine-solutions/handling"}
diff --git a/rust/tests/handling_test/a.txt b/rust/tests/handling_test/a.txt
new file mode 100644
index 00000000..7dde7fad
--- /dev/null
+++ b/rust/tests/handling_test/a.txt
@@ -0,0 +1 @@
+content to be written
\ No newline at end of file
diff --git a/rust/tests/handling_test/src/main.rs b/rust/tests/handling_test/src/main.rs
new file mode 100644
index 00000000..e8c66fec
--- /dev/null
+++ b/rust/tests/handling_test/src/main.rs
@@ -0,0 +1,63 @@
+use std::fs::{File, OpenOptions};
+use std::io::prelude::*;
+use std::io::{ErrorKind, Write};
+use handling::*;
+
+fn main() {
+    let path = "a.txt";
+    File::create(path).unwrap();
+    open_or_create(path, "content to be written");
+
+    let mut file = File::open(path).unwrap();
+
+    let mut s = String::new();
+    file.read_to_string(&mut s).unwrap();
+    println!("{}", s);
+    // output: content to be written
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use std::fs;
+	use std::panic;
+
+	fn get_file_content(filename: &str) -> String {
+		let mut file = File::open(filename).unwrap();
+		let mut s = String::new();
+		file.read_to_string(&mut s).unwrap();
+		fs::remove_file(filename).unwrap();
+		return s;
+	}
+
+	#[test]
+	fn test_if_file_exists() {
+		let filename = "test_existing_file.txt";
+		let content = "hello world!";
+		File::create(filename).unwrap();
+		open_or_create(filename, content);
+
+		assert_eq!(content, get_file_content(filename));
+	}
+
+	#[test]
+	fn test_create_file() {
+		let file = "no_existing_file.txt";
+		let content = "hello world!";
+		open_or_create(file, content);
+
+		assert_eq!(content, get_file_content(file));
+	}
+	#[test]
+	fn test_error_case() {
+		let filename = "hello.txt";
+		File::create(filename).unwrap();
+		let mut perms = fs::metadata(filename).unwrap().permissions();
+		perms.set_readonly(true);
+		fs::set_permissions(filename, perms).unwrap();
+
+		let result = panic::catch_unwind(|| open_or_create(filename, "test"));
+		fs::remove_file(filename).unwrap();
+		assert!(result.is_err());
+	}
+}
diff --git a/rust/tests/how_many_references_test/Cargo.lock b/rust/tests/how_many_references_test/Cargo.lock
new file mode 100644
index 00000000..a7356cd1
--- /dev/null
+++ b/rust/tests/how_many_references_test/Cargo.lock
@@ -0,0 +1,12 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "how_many_references"
+version = "0.1.0"
+
+[[package]]
+name = "how_many_references_test"
+version = "0.1.0"
+dependencies = [
+ "how_many_references",
+]
diff --git a/rust/tests/how_many_references_test/Cargo.toml b/rust/tests/how_many_references_test/Cargo.toml
new file mode 100644
index 00000000..e2a00417
--- /dev/null
+++ b/rust/tests/how_many_references_test/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "how_many_references_test"
+version = "0.1.0"
+authors = ["lee <lee-dasilva@hotmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+how_many_references = { path = "../../../../rust-piscine-solutions/how_many_references"}
diff --git a/rust/tests/how_many_references_test/src/main.rs b/rust/tests/how_many_references_test/src/main.rs
new file mode 100644
index 00000000..7ccbddad
--- /dev/null
+++ b/rust/tests/how_many_references_test/src/main.rs
@@ -0,0 +1,103 @@
+use how_many_references::*;
+
+fn main() {
+    let a = Rc::new(String::from("a"));
+    let b = Rc::new(String::from("b"));
+    let c = Rc::new(String::from("c"));
+
+    let a1 = Rc::new(String::from("a"));
+
+    let mut new_node = Node::new(vec![a.clone()]);
+    new_node.add_ele(b.clone());
+    new_node.add_ele(a.clone());
+    new_node.add_ele(c.clone());
+    new_node.add_ele(a.clone());
+
+    println!("a: {:?}", how_many_references(&a));
+    println!("b: {:?}", how_many_references(&b));
+    println!("c: {:?}", how_many_references(&c));
+    new_node.rm_all_ref(a1.clone());
+    new_node.rm_all_ref(a.clone());
+
+    println!("a: {:?}", how_many_references(&a));
+    println!("b: {:?}", how_many_references(&b));
+    println!("c: {:?}", how_many_references(&c));
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_add_ele() {
+        let a = Rc::new(String::from("a"));
+        let b = Rc::new(String::from("b"));
+        let c = Rc::new(String::from("c"));
+
+        let mut new_node = Node::new(vec![a.clone()]);
+        new_node.add_ele(a.clone());
+        new_node.add_ele(b.clone());
+        new_node.add_ele(c.clone());
+
+        assert_eq!(new_node.value, vec![a.clone(), a, b, c]);
+    }
+    #[test]
+    fn test_how_many_references() {
+        let a = Rc::new(String::from("a"));
+        let b = Rc::new(String::from("b"));
+        let c = Rc::new(String::from("c"));
+        let d = Rc::new(String::from("d"));
+        let mut new_node = Node::new(vec![]);
+        new_node.add_ele(b.clone());
+        new_node.add_ele(a.clone());
+        new_node.add_ele(c.clone());
+        new_node.add_ele(a.clone());
+
+        assert_eq!(how_many_references(&d), 1);
+        assert_eq!(how_many_references(&a), 3);
+        assert_eq!(how_many_references(&b), 2);
+        assert_eq!(how_many_references(&c), 2);
+    }
+
+    #[test]
+    fn test_rm_all_ref() {
+        let a = Rc::new(String::from("a"));
+        let b = Rc::new(String::from("b"));
+        let c = Rc::new(String::from("c"));
+        let d = Rc::new(String::from("d"));
+
+        let a1 = Rc::new(String::from("a"));
+        let b1 = Rc::new(String::from("b"));
+        let c1 = Rc::new(String::from("c"));
+        let d1 = Rc::new(String::from("d"));
+        let mut new_node = Node::new(vec![
+            d.clone(),
+            d.clone(),
+            b.clone(),
+            a.clone(),
+            c.clone(),
+            a.clone(),
+            d.clone(),
+        ]);
+
+        new_node.rm_all_ref(a1.clone());
+        assert_eq!(how_many_references(&a), 3);
+        new_node.rm_all_ref(a.clone());
+        assert_eq!(how_many_references(&a), 1);
+
+        new_node.rm_all_ref(b1.clone());
+        assert_eq!(how_many_references(&b), 2);
+        new_node.rm_all_ref(b.clone());
+        assert_eq!(how_many_references(&b), 1);
+
+        new_node.rm_all_ref(c1.clone());
+        assert_eq!(how_many_references(&c), 2);
+        new_node.rm_all_ref(c.clone());
+        assert_eq!(how_many_references(&c), 1);
+
+        new_node.rm_all_ref(d1.clone());
+        assert_eq!(how_many_references(&d), 4);
+        new_node.rm_all_ref(d.clone());
+        assert_eq!(how_many_references(&d), 1);
+    }
+}
diff --git a/rust/tests/panic_test/Cargo.lock b/rust/tests/panic_test/Cargo.lock
new file mode 100644
index 00000000..48ea8173
--- /dev/null
+++ b/rust/tests/panic_test/Cargo.lock
@@ -0,0 +1,12 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "panic"
+version = "0.1.0"
+
+[[package]]
+name = "panic_test"
+version = "0.1.0"
+dependencies = [
+ "panic",
+]
diff --git a/rust/tests/panic_test/Cargo.toml b/rust/tests/panic_test/Cargo.toml
new file mode 100644
index 00000000..46274a8d
--- /dev/null
+++ b/rust/tests/panic_test/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "panic_test"
+version = "0.1.0"
+authors = ["lee <lee-dasilva@hotmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+panic = { path = "../../../../rust-piscine-solutions/panic"} 
\ No newline at end of file
diff --git a/rust/tests/panic_test/src/main.rs b/rust/tests/panic_test/src/main.rs
new file mode 100644
index 00000000..96620325
--- /dev/null
+++ b/rust/tests/panic_test/src/main.rs
@@ -0,0 +1,29 @@
+use panic::*;
+use std::fs::{self, File};
+
+fn main() {
+    let filename = "created.txt";
+    File::create(filename).unwrap();
+    let a = open_file(filename);
+    println!("{:?}", a);
+    fs::remove_file(filename).unwrap();
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	#[test]
+	#[should_panic]
+	fn test_opening() {
+		open_file("file.txt");
+	}
+
+	#[test]
+	fn test_opening_existing() {
+		let filename = "created.txt";
+		File::create(filename).unwrap();
+		open_file(filename);
+		fs::remove_file(filename).unwrap();
+	}
+}
diff --git a/rust/tests/profanity_filter_test/Cargo.lock b/rust/tests/profanity_filter_test/Cargo.lock
new file mode 100644
index 00000000..f4fb40ac
--- /dev/null
+++ b/rust/tests/profanity_filter_test/Cargo.lock
@@ -0,0 +1,99 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "autocfg"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
+
+[[package]]
+name = "chrono"
+version = "0.4.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "670ad68c9088c2a963aaa298cb369688cf3f9465ce5e2d4ca10e6e0098a1ce73"
+dependencies = [
+ "libc",
+ "num-integer",
+ "num-traits",
+ "time",
+ "winapi",
+]
+
+[[package]]
+name = "libc"
+version = "0.2.81"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1482821306169ec4d07f6aca392a4681f66c75c9918aa49641a2595db64053cb"
+
+[[package]]
+name = "num-integer"
+version = "0.1.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d2cc698a63b549a70bc047073d2949cce27cd1c7b0a4a862d08a8031bc2801db"
+dependencies = [
+ "autocfg",
+ "num-traits",
+]
+
+[[package]]
+name = "num-traits"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9a64b1ec5cda2586e284722486d802acf1f7dbdc623e2bfc57e65ca1cd099290"
+dependencies = [
+ "autocfg",
+]
+
+[[package]]
+name = "profanity_filter"
+version = "0.1.0"
+dependencies = [
+ "chrono",
+]
+
+[[package]]
+name = "profanity_filter_test"
+version = "0.1.0"
+dependencies = [
+ "chrono",
+ "profanity_filter",
+]
+
+[[package]]
+name = "time"
+version = "0.1.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6db9e6914ab8b1ae1c260a4ae7a49b6c5611b40328a735b21862567685e73255"
+dependencies = [
+ "libc",
+ "wasi",
+ "winapi",
+]
+
+[[package]]
+name = "wasi"
+version = "0.10.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1a143597ca7c7793eff794def352d41792a93c481eb1042423ff7ff72ba2c31f"
+
+[[package]]
+name = "winapi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
diff --git a/rust/tests/profanity_filter_test/Cargo.toml b/rust/tests/profanity_filter_test/Cargo.toml
new file mode 100644
index 00000000..955cc920
--- /dev/null
+++ b/rust/tests/profanity_filter_test/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "profanity_filter_test"
+version = "0.1.0"
+authors = ["lee <lee-dasilva@hotmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+profanity_filter = { path = "../../../../rust-piscine-solutions/profanity_filter"}
+chrono = "0.4.19"
diff --git a/rust/tests/profanity_filter_test/src/main.rs b/rust/tests/profanity_filter_test/src/main.rs
new file mode 100644
index 00000000..7a10ca74
--- /dev/null
+++ b/rust/tests/profanity_filter_test/src/main.rs
@@ -0,0 +1,77 @@
+use profanity_filter::*;
+
+fn main() {
+    let m0 = Message::new("hello there".to_string(), "toby".to_string(), format_date());
+    println!("{:?}", check_ms(&m0));
+    // output: (true, "hello there")
+  
+    let m1 = Message::new("".to_string(), "toby".to_string(), format_date());
+    println!("{:?}", check_ms(&m1));
+    // output: (false, "ERROR: illegal")
+  
+    let m2 = Message::new("you are stupid".to_string(), "toby".to_string(), format_date());
+    println!("{:?}", check_ms(&m2));
+    // output: (false, "ERROR: illegal")
+  
+    let m3 = Message::new("stupid".to_string(), "toby".to_string(), format_date());
+    println!("{:?}", check_ms(&m3));
+    // output: (false, "ERROR: illegal")
+}
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+  use chrono::prelude::Utc;
+
+  fn test_format() -> String {
+    Utc::now().format("%a %b %e %T %Y").to_string()
+  }
+
+  #[test]
+  fn test_time_format() {
+    assert_eq!(format_date(), test_format());
+  }
+
+  #[test]
+  fn test_error_ms() {
+    let v = vec![
+      Message::new("".to_string(), "toby".to_string(), format_date()),
+      Message::new("stupid".to_string(), "jack".to_string(), format_date()),
+      Message::new(
+        "you are stupid".to_string(),
+        "jacob".to_string(),
+        format_date(),
+      ),
+    ];
+    for value in v {
+      let (t, _) = check_ms(&value);
+      assert!(!t);
+    }
+  }
+
+  #[test]
+  fn test_ok_ms() {
+    let v = vec![
+      Message::new(
+        "get out of the car".to_string(),
+        "police".to_string(),
+        format_date(),
+      ),
+      Message::new("no!".to_string(), "thief".to_string(), format_date()),
+      Message::new(
+        "get the werewolf".to_string(),
+        "police".to_string(),
+        format_date(),
+      ),
+      Message::new(
+        "wait the wha...".to_string(),
+        "thief".to_string(),
+        format_date(),
+      ),
+    ];
+    for value in v {
+      let (t, _) = check_ms(&value);
+      assert!(t);
+    }
+  }
+}
diff --git a/rust/tests/project_motion_test/Cargo.lock b/rust/tests/project_motion_test/Cargo.lock
new file mode 100644
index 00000000..5e0f535f
--- /dev/null
+++ b/rust/tests/project_motion_test/Cargo.lock
@@ -0,0 +1,12 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "project_motion"
+version = "0.1.0"
+
+[[package]]
+name = "project_motion_test"
+version = "0.1.0"
+dependencies = [
+ "project_motion",
+]
diff --git a/rust/tests/project_motion_test/Cargo.toml b/rust/tests/project_motion_test/Cargo.toml
new file mode 100644
index 00000000..b088cb33
--- /dev/null
+++ b/rust/tests/project_motion_test/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "project_motion_test"
+version = "0.1.0"
+authors = ["lee <lee-dasilva@hotmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+project_motion = { path = "../../../../rust-piscine-solutions/project_motion"}
diff --git a/rust/tests/project_motion_test/src/main.rs b/rust/tests/project_motion_test/src/main.rs
new file mode 100644
index 00000000..13d4c146
--- /dev/null
+++ b/rust/tests/project_motion_test/src/main.rs
@@ -0,0 +1,56 @@
+use project_motion::*;
+
+fn main() {
+    let mut obj = Object::throw_object(50.0, 150.0);
+    println!("{:?}", obj.next());
+    println!("{:?}", obj.next());
+    println!("{:?}", obj.next());
+    println!("{:?}", obj.next());
+    println!("{:?}", obj.next());
+    println!("{:?}", obj.next());
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_short_distance() {
+        let mut object = Object::throw_object(50.0, 20.0);
+
+        assert_eq!(object.next(), Some(Object { distance: 50.0, velocity: 50.0, height: 15.1, time: 1.0 }));
+        assert_eq!(object, Object { distance: 50.0, velocity: 50.0, height: 15.1, time: 1.0 });
+
+        assert!(object.next().is_none(), "{:?} instead of None", object);
+        assert!(object.next().is_none(), "{:?} instead of None", object);
+    }
+
+    #[test]
+    fn test_media_distance() {
+        let mut object = Object::throw_object(100.0, 30.0);
+
+        assert_eq!(object.next(), Some(Object { distance: 100.0, velocity: 100.0, height: 25.1, time: 1.0 }));
+        assert_eq!(object, Object { distance: 100.0, velocity: 100.0, height: 25.1, time: 1.0 });
+
+        assert_eq!(object.next(), Some(Object { distance: 200.0, velocity: 100.0, height: 5.5, time: 2.0 }));
+        assert_eq!(object, Object { distance: 200.0, velocity: 100.0, height: 5.5, time: 2.0 });
+
+        assert!(object.next().is_none(), "{:?} instead of None", object);
+    }
+
+    #[test]
+    fn test_long_distance() {
+        let mut object = Object::throw_object(120.0, 100.0);
+
+        assert_eq!(object.next(), Some(Object { distance: 120.0, velocity: 120.0, height: 95.1, time: 1.0 }));
+        assert_eq!(object, Object { distance: 120.0, velocity: 120.0, height: 95.1, time: 1.0 });
+
+        assert_eq!(object.next(), Some(Object { distance: 240.0, velocity: 120.0, height: 75.5, time: 2.0 }));
+        assert_eq!(object, Object { distance: 240.0, velocity: 120.0, height: 75.5, time: 2.0 });
+
+        assert_eq!(object.next(), Some(Object { distance: 360.0, velocity: 120.0, height: 31.4, time: 3.0 }));
+        assert_eq!(object, Object { distance: 360.0, velocity: 120.0, height: 31.4, time: 3.0 });
+        
+        assert!(object.next().is_none(), "{:?} instead of None", object);
+    }
+}
diff --git a/rust/tests/question_mark_test/Cargo.lock b/rust/tests/question_mark_test/Cargo.lock
new file mode 100644
index 00000000..1fbf15c0
--- /dev/null
+++ b/rust/tests/question_mark_test/Cargo.lock
@@ -0,0 +1,12 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "question_mark"
+version = "0.1.0"
+
+[[package]]
+name = "question_mark_test"
+version = "0.1.0"
+dependencies = [
+ "question_mark",
+]
diff --git a/rust/tests/question_mark_test/Cargo.toml b/rust/tests/question_mark_test/Cargo.toml
new file mode 100644
index 00000000..d970a526
--- /dev/null
+++ b/rust/tests/question_mark_test/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "question_mark_test"
+version = "0.1.0"
+authors = ["lee <lee-dasilva@hotmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+question_mark = { path = "../../../../rust-piscine-solutions/question_mark"}
diff --git a/rust/tests/question_mark_test/src/main.rs b/rust/tests/question_mark_test/src/main.rs
new file mode 100644
index 00000000..c2398e29
--- /dev/null
+++ b/rust/tests/question_mark_test/src/main.rs
@@ -0,0 +1,47 @@
+use question_mark::*;
+
+fn main() {
+    let a = One {
+        first_layer : Some(Two {
+            second_layer: Some(Three {
+                third_layer: Some(Four {
+                    fourth_layer: Some(1000)
+                })
+            })
+        })
+    };
+
+    // output: 1000
+    println!("{:?}", match a.get_fourth_layer() {
+        Some(e) => e,
+        None => 0
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_value() {
+        let a = One {
+            first_layer : Some(Two {
+                second_layer: Some(Three {
+                    third_layer: Some(Four {
+                        fourth_layer: Some(1000)
+                    })
+                })
+            })
+        };
+        let b = One {
+            first_layer : Some(Two {
+                second_layer: Some(Three {
+                    third_layer: Some(Four {
+                        fourth_layer: Some(3)
+                    })
+                })
+            })
+        };
+        assert_eq!(a.get_fourth_layer(), Some(1000));
+        assert_eq!(b.get_fourth_layer(), Some(3));
+    }
+}
diff --git a/rust/tests/ref_cell_test/Cargo.lock b/rust/tests/ref_cell_test/Cargo.lock
new file mode 100644
index 00000000..04f405cb
--- /dev/null
+++ b/rust/tests/ref_cell_test/Cargo.lock
@@ -0,0 +1,12 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ref_cell"
+version = "0.1.0"
+
+[[package]]
+name = "ref_cell_test"
+version = "0.1.0"
+dependencies = [
+ "ref_cell",
+]
diff --git a/rust/tests/ref_cell_test/Cargo.toml b/rust/tests/ref_cell_test/Cargo.toml
new file mode 100644
index 00000000..acacc6db
--- /dev/null
+++ b/rust/tests/ref_cell_test/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "ref_cell_test"
+version = "0.1.0"
+authors = ["lee <lee-dasilva@hotmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+ref_cell = { path = "../../../../rust-piscine-solutions/ref_cell"}
diff --git a/rust/tests/ref_cell_test/src/main.rs b/rust/tests/ref_cell_test/src/main.rs
new file mode 100644
index 00000000..9ba1908e
--- /dev/null
+++ b/rust/tests/ref_cell_test/src/main.rs
@@ -0,0 +1,158 @@
+use ref_cell::*;
+
+fn main() {
+    // initialize the worker
+    let Logger = Worker::new(1);
+
+    // initialize the tracker, with the max number of
+    // called references as 10
+    let track = Tracker::new(&Logger, 10);
+
+    let _a = Logger.track_value.clone();    // |\
+    let _a1 = Logger.track_value.clone();   // | -> increase the Rc to 4 references
+    let _a2 = Logger.track_value.clone();   // |/
+
+    // take a peek of how much we already used from our quota
+    track.peek(&Logger.track_value);
+
+    let _b = Logger.track_value.clone();  // |\
+    let _b1 = Logger.track_value.clone(); // |  -> increase the Rc to 8 references
+    let _b2 = Logger.track_value.clone(); // | /
+    let _b3 = Logger.track_value.clone(); // |/
+
+    // this will set the value and making a verification of
+    // how much we already used of our quota
+    track.set_value(&Logger.track_value);
+
+    let _c = Logger.track_value.clone(); // | -> increase the Rc to 9 references
+
+    // this will set the value and making a verification of
+    // how much we already used of our quota
+    track.set_value(&Logger.track_value);
+
+    let _c1 = Logger.track_value.clone(); // | -> increase the Rc to 10 references, this will be the limit
+
+    track.set_value(&Logger.track_value);
+
+    for (k ,v) in Logger.mapped_messages.into_inner() {
+        println!("{:?}", (k ,v));
+    }
+    println!("{:?}", Logger.all_messages.into_inner());
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_module() {
+        #[derive(Clone, Debug)]
+        struct TestMs {
+            value: Rc<usize>,
+            ms: RefCell<Vec<String>>,
+            correct: Vec<String>,
+        }
+
+        impl Logger for TestMs {
+            fn warning(&self, message: &str) {
+                self.ms.borrow_mut().push(message.to_string());
+            }
+            fn info(&self, message: &str) {
+                self.ms.borrow_mut().push(message.to_string());
+            }
+            fn error(&self, message: &str) {
+                self.ms.borrow_mut().push(message.to_string());
+            }
+        }
+
+        let l = TestMs {
+            value: Rc::new(115),
+            ms: RefCell::new(vec![]),
+            correct: vec![
+              String::from("Info: you are using up too 40% of your quote"),
+              String::from("Warning: you have used up over 80% of your quota! Proceeds with precaution"),
+              String::from("Error: you are over your quota!")
+            ],
+        };
+
+        let track = Tracker::new(&l, 5);
+        let _a = l.value.clone();
+        track.peek(&l.value); // 40%
+        let _a1 = l.value.clone();
+        let _a2 = l.value.clone();
+        track.set_value(&l.value); // 80%
+        let _a3 = l.value.clone();
+        track.set_value(&l.value); // 100%
+
+        for (i, v) in l.ms.into_inner().iter().enumerate() {
+            assert_eq!(v, &l.correct[i])
+        }
+    }
+
+    #[test]
+    fn test_module_usage_hasmap() {
+        let log = Worker::new(1000);
+        let track = Tracker::new(&log, 12);
+        let _clone_test = log.track_value.clone();
+        let _clone_test1 = log.track_value.clone();
+        let _clone_test2 = log.track_value.clone();
+        let _clone_test3 = log.track_value.clone();
+        let _clone_test4 = log.track_value.clone();
+        let _clone_test5 = log.track_value.clone();
+        let _clone_test6 = log.track_value.clone();
+        let _clone_test7 = log.track_value.clone();
+        
+        // warning: 75% of the quota
+        track.set_value(&log.track_value);
+        assert_eq!(log.mapped_messages.borrow().get("Warning").unwrap(), "you have used up over 75% of your quota! Proceeds with precaution");
+
+        let _clone_test8 = log.track_value.clone();
+
+        // warning: 83% of the quota <- most resent of the messages last onw to be added to the hashmap
+        track.set_value(&log.track_value);
+        assert_eq!(log.mapped_messages.borrow().get("Warning").unwrap(), "you have used up over 83% of your quota! Proceeds with precaution");
+
+        // info: 83%
+        track.peek(&log.track_value);
+        assert_eq!(log.mapped_messages.borrow().get("Info").unwrap(), "you are using up too 83% of your quote");
+
+        let _clone_test9 = log.track_value.clone();
+        // info: 91%
+        track.peek(&log.track_value);
+        assert_eq!(log.mapped_messages.borrow().get("Info").unwrap(), "you are using up too 91% of your quote");
+
+        let _clone_test10 = log.track_value.clone();
+        // error: passed the quota
+        track.set_value(&log.track_value);
+        assert_eq!(log.mapped_messages.borrow().get("Error").unwrap(), "you are over your quota!");
+    }
+
+    #[test]
+    fn test_module_usage_vector() {
+        let correct = vec![
+            "Info: you are using up too 40% of your quote",
+            "Warning: you have used up over 80% of your quota! Proceeds with precaution",
+            "Info: you are using up too 80% of your quote", "Error: you are over your quota!"
+        ];
+        let log = Worker::new(1);
+        let track = Tracker::new(&log, 5);
+        let _a = log.track_value.clone();
+        // info: 40%
+        track.peek(&log.track_value);
+        let _a1 = log.track_value.clone();
+        let _a2 = log.track_value.clone();
+
+        // warning: 80%
+        track.set_value(&log.track_value);
+        // info: 80%
+        track.peek(&log.track_value);
+        let _a3 = log.track_value.clone();
+
+        // error: passed the quota
+        track.set_value(&log.track_value);
+        
+        for (i, v) in log.all_messages.into_inner().iter().enumerate() {
+            assert_eq!(v, correct[i]);
+        }
+    }
+}
diff --git a/rust/tests/sales_test/Cargo.lock b/rust/tests/sales_test/Cargo.lock
new file mode 100644
index 00000000..b3dffd2f
--- /dev/null
+++ b/rust/tests/sales_test/Cargo.lock
@@ -0,0 +1,12 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "sales"
+version = "0.1.0"
+
+[[package]]
+name = "sales_test"
+version = "0.1.0"
+dependencies = [
+ "sales",
+]
diff --git a/rust/tests/sales_test/Cargo.toml b/rust/tests/sales_test/Cargo.toml
new file mode 100644
index 00000000..42d70f49
--- /dev/null
+++ b/rust/tests/sales_test/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "sales_test"
+version = "0.1.0"
+authors = ["lee <lee-dasilva@hotmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+sales = { path = "../../../../rust-piscine-solutions/sales"}
diff --git a/rust/tests/sales_test/src/main.rs b/rust/tests/sales_test/src/main.rs
new file mode 100644
index 00000000..ded9b1d9
--- /dev/null
+++ b/rust/tests/sales_test/src/main.rs
@@ -0,0 +1,133 @@
+use sales::*;
+
+fn main() {
+    let store = Store::new(vec![
+        (String::from("product A"), 1.23),
+        (String::from("product B"), 23.1),
+        (String::from("product C"), 3.12)]);
+
+    println!("{:?}", store);
+    // output:
+    // Store { products: [("product A", 1.23), ("product B", 23.1), ("product C", 3.12)] }
+
+    let mut cart = Cart::new();
+    cart.insert_item(&store, String::from("product A"));
+    cart.insert_item(&store, String::from("product B"));
+    cart.insert_item(&store, String::from("product C"));
+    
+    println!("{:?}", cart.generate_receipt());
+    // output:
+    // [1.17, 2.98, 22.07]
+
+    println!("{:?}", cart);
+    // output:
+    // Cart { items: [("product A", 1.23), ("product B", 23.1), ("product C", 3.12)], receipt: [1.17, 2.98, 22.07] }
+}
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[derive(Debug)]
+    struct Tests {
+        store: Store,
+        carts: Vec<(Cart, Vec<f32>)>,
+    }
+
+    fn add_items(s: &Store, items: Vec<&str>, c: &mut Cart) {
+        for item in items.iter() {
+            c.insert_item(s, item.to_string());
+        }
+    }
+
+    impl Tests {
+        fn new() -> Tests {
+            let store = Store::new(vec![
+                (String::from("product A"), 1.23),
+                (String::from("product B"), 23.1),
+                (String::from("product C"), 3.12),
+                (String::from("product D"), 9.75),
+                (String::from("product E"), 1.75),
+                (String::from("product F"), 23.75),
+                (String::from("product G"), 2.75),
+                (String::from("product H"), 1.64),
+                (String::from("product I"), 15.23),
+                (String::from("product J"), 2.10),
+                (String::from("product K"), 54.91),
+                (String::from("product L"), 43.99),
+            ]);
+
+            let mut c = Cart::new();
+            let mut c1 = Cart::new();
+            let mut c2 = Cart::new();
+            let mut c3 = Cart::new();
+            add_items(&store, vec!["product A", "product B", "product C"], &mut c);
+            let sol = vec![1.17, 2.98, 22.07];
+            add_items(
+                &store,
+                vec![
+                    "product A",
+                    "product B",
+                    "product C",
+                    "product D",
+                    "product E",
+                    "product F",
+                    "product G",
+                ],
+                &mut c1,
+            );
+            let sol1 = vec![1.17, 1.67, 2.62, 2.98, 9.31, 22.05, 22.67];
+            add_items(
+                &store,
+                vec![
+                    "product A",
+                    "product B",
+                    "product C",
+                    "product D",
+                    "product E",
+                    "product F",
+                    "product G",
+                    "product H",
+                    "product I",
+                ],
+                &mut c2,
+            );
+            let sol2 = vec![1.16, 1.55, 1.65, 2.6, 2.94, 9.2, 14.38, 21.8, 22.42];
+            add_items(
+                &store,
+                vec![
+                    "product A",
+                    "product B",
+                    "product C",
+                    "product D",
+                    "product E",
+                    "product F",
+                    "product G",
+                    "product H",
+                    "product I",
+                    "product J",
+                    "product K",
+                    "product L",
+                ],
+                &mut c3,
+            );
+            let sol3 = vec![
+                1.18, 1.58, 1.69, 2.02, 2.65, 3.01, 9.39, 14.67, 22.25, 22.88, 42.38, 52.89,
+            ];
+
+            Tests {
+                store,
+                carts: vec![(c, sol), (c1, sol1), (c2, sol2), (c3, sol3)],
+            }
+        }
+    }
+
+    #[test]
+    fn test_generate_receipt() {
+        let cases = Tests::new();
+
+        for (mut c, sol) in cases.carts.into_iter() {
+            assert_eq!(c.generate_receipt(), sol);
+            assert_eq!(c.receipt, sol);
+        }
+    }
+}
diff --git a/rust/tests/unwrap_and_expect_test/Cargo.lock b/rust/tests/unwrap_and_expect_test/Cargo.lock
new file mode 100644
index 00000000..a263be69
--- /dev/null
+++ b/rust/tests/unwrap_and_expect_test/Cargo.lock
@@ -0,0 +1,12 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "unwrap_and_expect"
+version = "0.1.0"
+
+[[package]]
+name = "unwrap_and_expect_test"
+version = "0.1.0"
+dependencies = [
+ "unwrap_and_expect",
+]
diff --git a/rust/tests/unwrap_and_expect_test/Cargo.toml b/rust/tests/unwrap_and_expect_test/Cargo.toml
new file mode 100644
index 00000000..05c2b114
--- /dev/null
+++ b/rust/tests/unwrap_and_expect_test/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "unwrap_and_expect_test"
+version = "0.1.0"
+authors = ["lee <lee-dasilva@hotmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+unwrap_and_expect = { path = "../../../../rust-piscine-solutions/unwrap_and_expect"}
diff --git a/rust/tests/unwrap_and_expect_test/src/main.rs b/rust/tests/unwrap_and_expect_test/src/main.rs
new file mode 100644
index 00000000..894679a3
--- /dev/null
+++ b/rust/tests/unwrap_and_expect_test/src/main.rs
@@ -0,0 +1,49 @@
+use unwrap_and_expect::*;
+
+fn main() {
+    println!("{:?}", unwrap_or(vec![1, 3, 2, 5]));
+    println!("{:?}", unwrap_or(vec![1, 3, 5]));
+    println!("{:?}", unwrap_err(vec![1, 3, 2, 5]));
+    println!("{:?}", unwrap(vec![1, 3, 5]));
+    println!("{:?}", unwrap_or_else(vec![1, 3, 5]));
+    println!("{:?}", unwrap_or_else(vec![3, 2, 6, 5]));
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    #[should_panic(expected = "ERROR : (\"There is a even value in the vector!\", [2])")]
+    fn test_expect() {
+        expect(vec![1, 3, 2, 5]);
+    }
+    #[test]
+    #[should_panic(expected = "called `Result::unwrap()` on an `Err` value: (\"There is a even value in the vector!\", [2])")]
+    fn test_unwrap() {
+        unwrap(vec![1, 3, 2, 5]);
+    }
+    #[test]
+    #[should_panic]
+    fn test_unwrap_err() {
+        unwrap_err(vec![1, 3, 5]);
+    }
+    #[test]
+    fn test_unwrap_or() {
+        assert_eq!(unwrap_or(vec![1, 3, 2, 5]), vec![]);
+    }
+    #[test]
+    fn test_unwrap_or_else() {
+        assert_eq!(unwrap_or_else(vec![1, 3, 5]), vec![2, 4, 6]);
+        assert_eq!(unwrap_or_else(vec![6, 8, 3, 2, 5, 4]), vec![6, 8, 2, 4]);
+    }
+    #[test]
+    fn test_ok() {
+        assert_eq!(expect(vec![1, 3, 5]), vec![2, 4, 6]);
+        assert_eq!(unwrap_or(vec![1, 3, 5]), vec![2, 4, 6]);
+        assert_eq!(unwrap_or_else(vec![1, 3, 5]), vec![2, 4, 6]);
+        assert_eq!(unwrap(vec![1, 3, 5]), vec![2, 4, 6]);
+        assert_eq!(unwrap_err(vec![1, 2, 3, 4, 5]).0, "There is a even value in the vector!");
+        assert_eq!(unwrap_err(vec![1, 2, 3, 4, 5]).1, vec![2, 4]);
+    }
+}
diff --git a/subjects/banner/README.md b/subjects/banner/README.md
new file mode 100644
index 00000000..0f7fc5e2
--- /dev/null
+++ b/subjects/banner/README.md
@@ -0,0 +1,110 @@
+## banner
+
+### Instructions
+
+`Result` is a better version of the `Option` type that describes possible error instead
+of possible absence
+
+Create a structure called `Flag` that as the following elements:
+
+- short_hand: String
+- long_hand: String
+- desc: String
+
+This structure must have associated to it a function called `opt_flag` that initializes the structure.
+Receiving two references strings and returns the structure `Flag`. It should be used like this:
+
+```rust
+    let d = Flag::opt_flag("diff", "gives the difference between two numbers");
+
+    println!("short hand: {}, long hand: {}, description: {}", d.short_hand, d.long_hand, d.desc);
+    // output: "short hand: -d, long hand: --diff, description: gives the difference between two numbers"
+```
+
+It will be given a second structure called `FlagsHandler` that has just one element: `flags: HashMap<(String, String), Callback>`
+And the following functions associated to it, for you to complete :
+
+- `add_flag`, that adds to the HashMap the flag and the Callback function.
+- `exec_func`, that executes the function using the flag provided and returns the result, that can
+  be either a string with the value from the callback or an error.
+
+It will also be provided a `type` called `Callback` being a function that is going to be used in the structure
+and functions above. This function will be the callback for the flag associated to it.
+
+You will have to create the following callback functions :
+
+- `div`, that converts the reference strings to `float`s and returns the `Result`, being the division of the `float`s or the standard (std) error: `ParseFloatError`.
+- `rem`, that converts the reference strings to `float`s and returns the `Result`, being the remainder of the division of the `float`s or the standard (std) error `ParseFloatError`.
+
+### Expected Function
+
+```rust
+use std::collections::HashMap;
+
+pub type Callback = fn(&str, &str) -> Result<String, ParseFloatError>;
+
+pub struct FlagsHandler {
+    pub flags: HashMap<(String, String), Callback>,
+}
+
+impl FlagsHandler {
+    pub fn add_flag(&mut self, flag: (String, String), func: Callback) {}
+    pub fn exec_func(&mut self, flag: (String, String), argv: &[&str]) -> String {}
+    }
+}
+
+pub struct Flag {
+    // expected public fields
+}
+
+impl Flag {
+    pub fn opt_flag(l_h: &str, d: &str) -> Flag {}
+}
+
+pub fn div(a: &str, b: &str) -> Result<String, ParseFloatError> {}
+pub fn rem(a: &str, b: &str) -> Result<String, ParseFloatError> {}
+
+```
+
+### Usage
+
+Here is a program to test your function
+
+```rust
+fn main() {
+    let mut handler = FlagsHandler { flags: HashMap::new() };
+
+    let d = Flag::opt_flag("division", "divides the values, formula (a / b)");
+    let r = Flag::opt_flag(
+        "remainder",
+        "remainder of the division between two values, formula (a % b)",
+    );
+
+    handler.add_flag((d.short_hand, d.long_hand), div);
+    handler.add_flag((r.short_hand, r.long_hand), rem);
+
+    println!("{:?}", handler.exec_func(("-d".to_string(), "--division".to_string()), &["1.0", "2.0"]));
+
+    println!("{:?}",handler.exec_func(("-r".to_string(), "--remainder".to_string()), &["2.0", "2.0"]));
+    
+    println!("{:?}",handler.exec_func(("-d".to_string(), "--division".to_string()), &["a", "2.0"]));
+    
+    println!("{:?}",handler.exec_func(("-r".to_string(), "--remainder".to_string()), &["2.0", "fd"]));
+}
+```
+
+And its output:
+
+```console
+student@ubuntu:~/[[ROOT]]/test$ cargo run
+"0.5"
+"0"
+"invalid float literal"
+"invalid float literal"
+student@ubuntu:~/[[ROOT]]/test$
+```
+
+### Notions
+
+- https://doc.rust-lang.org/rust-by-example/error/result.html
+- https://docs.rs/getopts/0.2.18/getopts/struct.Options.html#method.optflag
diff --git a/subjects/borrow_box/README.md b/subjects/borrow_box/README.md
new file mode 100644
index 00000000..c7cdafc5
--- /dev/null
+++ b/subjects/borrow_box/README.md
@@ -0,0 +1,83 @@
+## borrow box
+
+### Instructions
+
+You will have to create a **CRUD** functionality. Therefore creating the following functions :
+
+- `new`, that receives two players and initializes them with a name and a score. This functions should
+  return the structure wrapped in a Box.
+
+- `read_winner`, returns a tuple with the name and the score of the player who is winning.
+  In case none of the players are winning, it should return the same tuple with the string "Same score! tied" and the tied score.
+
+  - `update_score`, that receives the name of a player.
+  This function should increment the score of the player. The score should only be increased if it does not pass the `nbr_of_games`.
+  Example: if the nbr_of_games is 3 then the game should be best out of three. So if one play as 2 wins then
+  he is the winner and the function should not increase the score anymore for either players.
+
+- `delete`, that takes the ownership of the boxed game and returning a string : "Game deleted: id -> 0".
+
+### Expected Function
+
+```rust
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct Game {
+    // expected public fields
+}
+impl Game {
+    pub fn new(i: u32, pl1: String, pl2: String, n: u16) -> Box<Game> {}
+    pub fn read_winner(&self) -> (String, u16) {}
+    pub fn update_score(&mut self, user_name: String) {}
+    pub fn delete(self) -> String {}
+}
+```
+
+### Usage
+
+Here is a program to test your function
+
+```rust
+fn main() {
+    let mut game = Game::create_game(0, String::from("Joao"), String::from("Susana"), 5);
+    println!("{:?}", game.read_winner());
+    // output : ("Same score! tied", 0)
+
+    game.update_score(String::from("Joao"));
+    game.update_score(String::from("Joao"));
+    game.update_score(String::from("Susana"));
+    game.update_score(String::from("Susana"));
+    println!("{:?}", game.read_winner());
+    // output : ("Same score! tied", 2)
+
+    game.update_score(String::from("Joao"));
+    // this one will not count because it already 5 games played, the nbr_of_games
+    game.update_score(String::from("Susana"));
+    
+    println!("{:?}", game.read_winner());
+    // output : ("Joao", 3)
+
+    game.delete();
+    println!("{:?}", game.delete());
+    // output : "game deleted: id -> 0"
+
+    // game.read_winner();
+    // this will give error
+    // because the game was dropped, no longer exists on the heap
+}
+```
+
+And its output:
+
+```console
+student@ubuntu:~/[[ROOT]]/test$ cargo run
+("Same score! tied", 0)
+("Same score! tied", 2)
+("Joao", 3)
+"game deleted: id -> 0"
+student@ubuntu:~/[[ROOT]]/test$
+```
+
+
+### Notions
+
+- https://doc.rust-lang.org/book/ch15-01-box.html
diff --git a/subjects/box_it/README.md b/subjects/box_it/README.md
new file mode 100644
index 00000000..369f01de
--- /dev/null
+++ b/subjects/box_it/README.md
@@ -0,0 +1,53 @@
+## box_it
+
+### Instructions
+
+Create the following functions:
+
+- `transform_and_save_on_heap`, that receives a string with a number (that can or not have a k (kilo) suffix)
+  and transforms those numbers into `u32` and inserts it into a vector that must be saved in the heap using **Box**.
+
+- `take_value_ownership`, that takes the value (unboxed value) form the box and returns it
+
+### Expected Function
+
+```rust
+pub fn transform_and_save_on_heap(s: String) -> Box<Vec<u32>> {}
+pub fn take_value_ownership(a: Box<Vec<u32>>) -> Vec<u32> {}
+```
+
+### Usage
+
+Here is a program to test your function
+
+```rust
+fn main() {
+    let new_str = String::from("5.5k 8.9k 32");
+
+    // creating a variable and we save it in the Heap
+    let a_h = transform_and_save_on_heap(new_str);
+    println!("Box value : {:?}", &a_h);
+    println!("size occupied in the stack : {:?} bytes", (std::mem::size_of_val(&a_h)));
+    
+    let a_b_v = take_value_ownership(a_h);
+    println!("value : {:?}", &a_b_v);
+    println!("size occupied in the stack : {:?} bytes", (std::mem::size_of_val(&a_b_v)));
+    // whenever the box, in this case "a_h", goes out of scope it will be deallocated, freed
+}
+```
+
+And its output:
+
+```console
+student@ubuntu:~/[[ROOT]]/test$ cargo run
+Box value : [6800, 13500]
+size occupied in the stack : 8 bytes
+value : [6800, 13500]
+size occupied in the stack : 24 bytes
+student@ubuntu:~/[[ROOT]]/test$
+```
+
+### Notions
+
+- https://doc.rust-lang.org/book/ch15-00-smart-pointers.html
+- https://doc.rust-lang.org/book/ch15-01-box.html
diff --git a/subjects/box_recursion/README.md b/subjects/box_recursion/README.md
new file mode 100644
index 00000000..1f867924
--- /dev/null
+++ b/subjects/box_recursion/README.md
@@ -0,0 +1,79 @@
+## box_recursion
+
+### Instructions
+
+Using the given code create the following functions:
+
+- `new` that will initialize the `WorkEnvironment` as `None`
+- `add_worker`, that receives two strings, one being the type of worker and the other the name of the worker.
+- `remove_worker`, that removes the last worker that was placed in the `WorkEnvironment`, this functions should 
+  return a `Option` with the name of the worker.
+- `search_worker`, that return a tuple with the name and type of worker.
+
+You must also create a type called `Link` this will be the connection of the structures `WorkEnvironment` and `Worker`.
+Do not forget that this will be a recursion type and it must point to `None` if there is no workers.
+
+### Expected Function
+
+```rust
+pub struct WorkEnvironment {
+    pub grade: Link,
+}
+
+pub type Link = 
+
+pub struct Worker {
+    pub worker_type: String,
+    pub worker_name: String,
+    pub next_worker: Link,
+}
+
+impl WorkEnvironment {
+    pub fn new() -> WorkEnvironment {}
+    pub fn add_worker(&mut self, t: String, name: String) {}
+    pub fn remove_worker(&mut self) -> Option<String> {}
+    pub fn search_worker(&self) -> Option<(String, String)> {}
+}
+
+
+```
+
+### Usage
+
+Here is a program to test your function
+
+```rust
+fn main() {
+    let mut list = WorkEnvironment::new();
+    list.add_worker(String::from("CEO"), String::from("Marie"));
+    list.add_worker(String::from("Manager"), String::from("Monica"));
+    list.add_worker(String::from("Normal Worker"), String::from("Ana"));
+    list.add_worker(String::from("Normal Worker"), String::from("Alice"));
+    println!("{:?}", list);
+
+    println!("{:?}", list.search_worker());
+
+    list.remove_worker();
+    list.remove_worker();
+    list.remove_worker();
+    list.remove_worker();
+    println!("{:?}", list);
+}
+```
+
+And its output:
+
+```console
+student@ubuntu:~/[[ROOT]]/test$ cargo run
+WorkEnvironment { grade: Some(Worker { worker_type: "Normal Worker", worker_name: "Alice", next_worker: Some(Worker { worker_type: "Normal Worker", worker_name: "Ana", next_worker: Some(Worker { worker_type: "Manager", worker_name: "Monica", next_worker: Some(Worker { worker_type: "CEO", worker_name: "Marie", next_worker: None }) }) }) }) }
+Some(("Alice", "Normal Worker"))
+WorkEnvironment { grade: None }
+student@ubuntu:~/[[ROOT]]/test$
+```
+
+### Notions
+
+- https://doc.rust-lang.org/rust-by-example/custom_types/enum.html
+- https://doc.rust-lang.org/book/ch15-01-box.html
+- https://doc.rust-lang.org/std/option/
+- https://doc.rust-lang.org/book/ch15-01-box.html
\ No newline at end of file
diff --git a/subjects/boxing_todo/README.md b/subjects/boxing_todo/README.md
new file mode 100644
index 00000000..a1ffdc8b
--- /dev/null
+++ b/subjects/boxing_todo/README.md
@@ -0,0 +1,165 @@
+## boxing_todo
+
+### Instructions
+
+The objective is to do an api to parse a list of *todos* that is organized in a JSON file,
+handling all possible errors in a multiple error system.
+
+Organization of the JSON file:
+
+```json
+{
+    "title" : "TODO LIST FOR PISCINE RUST",
+    "tasks": [
+        { "id": 0, "description": "do this", "level": 0 },
+        { "id": 1, "description": "do that", "level": 5 }
+    ]
+}
+```
+
+Create a module in another file called **error.rs** that handles the boxing of errors.
+This module must implement an `enum` called `ParseErr` that will take care of the
+parsing errors, it must have the following elements:
+
+- Empty
+- Malformed, that has a dynamic boxed error as element
+
+A structure called `ReadErr` that will take care of the reading errors, having just an element called `child_err` of type `Box<dyn Error>`.
+
+For each data structure you will have to implement a function called `fmt` for the trait `Display` that writes
+out the message **"Fail to parse todo"** in case it's a parsing error, otherwise it writes the message
+**"Failed to read todo file"**.
+And for the `Error` trait the following functions:
+
+- `description` that returns a string literal that says:
+  - "Todo List parse failed: " for the `ParseErr`
+  - "Todo List read failed: " for the `ReadErr`.
+
+- `cause` that returns an `Option` with the error:
+  - For the `ReadErr` it must just return the option with the error
+  - For the `ParseErr` it will return an option that can be `None` if the tasks are **empty** otherwise the error, if
+  the parsing is **malformed**.
+
+In the **lib** file you will have to implement a function called `get_todo` that receives a string and returns a Result
+that can be the structure `TodoList` or a boxing error. This function must be able to deserialize the json file,
+basically it must parse and read the JSON file and return the `TodoList` if everything is fine otherwise the error.
+
+### Expected Function
+
+For **error.rs**
+
+```rust
+use std::fmt;
+use std::fmt::Display;
+use std::error::Error;
+
+pub enum ParseErr {
+    // expected public fields
+}
+
+// required by error trait
+impl Display for ParseErr {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    }
+}
+
+pub struct ReadErr {
+    // expected public fields
+}
+
+// required by error trait
+impl Display for ReadErr {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    }
+}
+
+impl Error for ReadErr {
+    fn description(&self) -> &str {}
+    fn cause(&self) -> Option<&dyn Error> {}
+}
+
+impl Error for ParseErr {
+    fn description(&self) -> &str {}
+    fn cause(&self) -> Option<&dyn Error> {}
+}
+
+```
+
+for **lib.rs**
+
+```rust
+mod error;
+use error::{ ParseErr, ReadErr };
+use std::error::Error;
+use serde::{ Deserialize, Serialize };
+
+#[derive(Serialize, Deserialize, Debug, Eq, PartialEq)]
+pub struct Task {
+    id: u32,
+    description: String,
+    level: u32,
+}
+
+#[derive(Serialize, Deserialize, Debug, Eq, PartialEq)]
+pub struct TodoList {
+    title: String,
+    tasks: Vec<Task>,
+}
+
+impl TodoList {
+    pub fn get_todo(path: &str) -> Result<TodoList, Box<dyn Error>> {}
+}
+```
+
+### Usage
+
+Here is a program to test your function.
+Note that you can create some todo list your self to test it, but you can find the JSON files that
+are being tested [here](https://github.com/01-edu/public/blob/master/subjects/boxing_todo)
+
+```rust
+mod lib;
+use lib::{ TodoList };
+
+fn main() {
+    let todos = TodoList::get_todo("todo.json");
+    match todos {
+        Ok(list) => println!("{:?}", list),
+        Err(e) => {
+            println!("{}{:?}", e.description(), e.cause());
+        }
+    }
+
+    let todos = TodoList::get_todo("no_todo_list.json");
+    match todos {
+        Ok(list) => println!("{:?}", list),
+        Err(e) => {
+            println!("{}{:?}", e.description(), e.cause());
+        }
+    }
+
+    let todos = TodoList::get_todo("malformed_object.json");
+    match todos {
+        Ok(list) => println!("{:?}", list),
+        Err(e) => {
+            println!("{}{:?}", e.description(), e.cause().unwrap());
+        }
+    }
+}
+```
+
+And its output:
+
+```console
+student@ubuntu:~/[[ROOT]]/test$ cargo run
+TodoList { title: "TODO LIST FOR PISCINE RUST", tasks: [Task { id: 0, description: "do this", level: 0 }, Task { id: 1, description: "do that", level: 5 }] }
+Todo List parse failed: None
+Todo List parse failed: Malformed(Error("missing field `title`", line: 1, column: 2))
+student@ubuntu:~/[[ROOT]]/test$
+```
+
+### Notions
+
+- https://serde.rs/
+- https://doc.rust-lang.org/stable/rust-by-example/error/multiple_error_types/boxing_errors.html
+- https://doc.rust-lang.org/stable/rust-by-example/trait/dyn.html
diff --git a/subjects/boxing_todo/malformed_object.json b/subjects/boxing_todo/malformed_object.json
new file mode 100644
index 00000000..9e26dfee
--- /dev/null
+++ b/subjects/boxing_todo/malformed_object.json
@@ -0,0 +1 @@
+{}
\ No newline at end of file
diff --git a/subjects/boxing_todo/todo.json b/subjects/boxing_todo/todo.json
new file mode 100644
index 00000000..2341ac78
--- /dev/null
+++ b/subjects/boxing_todo/todo.json
@@ -0,0 +1,7 @@
+{
+    "title" : "TODO LIST FOR PISCINE RUST",
+    "tasks": [
+        { "id": 0, "description": "do this", "level": 0 },
+        { "id": 1, "description": "do that", "level": 5 }
+    ]
+}
\ No newline at end of file
diff --git a/subjects/boxing_todo/todo_empty.json b/subjects/boxing_todo/todo_empty.json
new file mode 100644
index 00000000..9dfc54f5
--- /dev/null
+++ b/subjects/boxing_todo/todo_empty.json
@@ -0,0 +1,4 @@
+{
+    "title" : "TODO LIST FOR PISCINE RUST",
+    "tasks": []
+}
\ No newline at end of file
diff --git a/subjects/cipher/README.md b/subjects/cipher/README.md
new file mode 100644
index 00000000..e6454b0c
--- /dev/null
+++ b/subjects/cipher/README.md
@@ -0,0 +1,47 @@
+## cipher
+
+### Instructions
+
+The Atbash cipher is a encryption method in which each letter of a word is replaced with its mirror letter in the alphabet
+
+Your objective is to create a function called `cipher` this must return a Result wrapped in an Option, this result should return either a boolean
+or an Error being the structure `CipherError`. This structure should be the error type for the function `cipher`
+
+This function should compare the original string wih the ciphered string. returning true if the cipher is correct otherwise the error type
+CipherErr with the a true or false if it is validated and the proper atbash cipher.
+
+### Expected Function
+
+```rust
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct CipherError {
+    // expected public fields
+}
+impl CipherError {
+    pub fn new(validation: bool, expected: String) -> CipherError {}
+}
+pub fn cipher(original: &str, ciphered: &str) -> Option<Result<bool, CipherError>> {}
+```
+
+### Usage
+
+Here is a program to test your function
+
+```rust
+fn main() {
+    println!("{:?}", cipher("1Hello 2world!", "1Svool 2dliow!"));
+    println!("{:?}", cipher("1Hello 2world!", "svool"));
+    println!("{:?}", cipher("", "svool"));
+}
+```
+
+And its output:
+
+```console
+student@ubuntu:~/[[ROOT]]/test$ cargo run
+Some(Ok(true))
+Some(Err(CipherError { validation: false, expected: "1Svool 2dliow!" }))
+None
+student@ubuntu:~/[[ROOT]]/test$
+```
diff --git a/subjects/drop_the_thread/README.md b/subjects/drop_the_thread/README.md
new file mode 100644
index 00000000..5d034154
--- /dev/null
+++ b/subjects/drop_the_thread/README.md
@@ -0,0 +1,109 @@
+## drop_the_thread
+
+### Instructions
+
+"Interior mutability is a design pattern in Rust that allows you to mutate data even when there are immutable references to that data"
+
+You must create a Drop checker API. For this you must create:
+
+- Two structures:
+  - `Workers` that will have two fields:
+    - `drops` that will save the number of dropped threads
+    - `states` that will save a state of multiple threads.
+      If the thread is not dropped, the state will be false otherwise true.
+  - `Thread` that will have the following fields:
+    - `pid`, the id of the thread
+    - `cmd`, the name of the thread
+    - `parent`, that will be the link to the structure `Workers` (Tip: this must be a reference to the structure Workers)
+
+- Implementation of each structure:
+  - `Workers` :
+    - `new`, that creates a default worker
+    - `new_worker`, that returns a tuple with the `pid` and a new `Thread`,
+      this function must receive a `String` being the `cmd`
+      - `is_dropped`, that receives a `pid` and returns a `bool` that indicates the state of the thread by using the `pid`
+      - `track_worker`, it should return a `usize`, that will be the last available index of the `states` vector, being the new next thread
+    - `add_drop`, this function must be **called by the `Drop` trait**. It will receive a `pid` that will be used to change the
+      state of the thread. If the state of that thread is `true` then it will panic with the message ("Cannot drop {}, because its already dropped", pid).
+      Otherwise it should change the state to true and increment the `drops` field by one.
+
+  - `Thread`:
+    - `new_thread`, that initializes a new thread
+    - `skill`, that drops the thread
+
+- You must implement for the structure `Thread` the `Drop` trait. In this trait you must call the function `add_drop` so that the state of the thread changes
+
+### Expected Function
+
+```rust
+use std::cell::{RefCell, Cell};
+
+#[derive(Debug, Default, Clone, Eq, PartialEq)]
+pub struct Workers {
+    pub drops: Cell<usize>,
+    pub state: RefCell<Vec<bool>>
+}
+
+impl Workers {
+    pub fn new() -> Workers {}
+    pub fn new_worker(&self, c: String) -> (usize, Thread) {}
+    pub fn track_worker(&self) -> usize {}
+    pub fn is_dropped(&self, id: usize) -> bool {}
+    pub fn add_drop(&self, id: usize) {}
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct Thread<'a> {
+    // expected public fields
+}
+
+impl<'a> Thread<'a> {
+    pub fn new_thread(p: usize, c: String, t: &'a Workers) -> Thread {}
+    pub fn skill(self) {}
+}
+```
+
+### Usage
+
+Here is a program to test your function
+
+```rust
+use std::rc::Rc;
+
+fn main() {
+    let worker = Workers::new();
+    let (id, thread) = worker.new_worker(String::from("command"));
+    let (id1, thread1) = worker.new_worker(String::from("command1"));
+
+    thread.skill();
+
+    println!("{:?}", (worker.is_dropped(id), id, &worker.drops));
+
+    thread1.skill();
+    println!("{:?}", (worker.is_dropped(id1), id1, &worker.drops));
+
+    let (id2, thread2) = worker.new_worker(String::from("command2"));
+    let thread2 = Rc::new(thread2);
+    let thread2_clone = thread2.clone();
+
+    drop(thread2_clone);
+
+    println!("{:?}", (worker.is_dropped(id2), id2, &worker.drops, Rc::strong_count(&thread2)));
+}
+```
+
+And its output:
+
+```console
+student@ubuntu:~/[[ROOT]]/test$ cargo run
+(true, 0, Cell { value: 1 })
+(true, 1, Cell { value: 2 })
+(false, 2, Cell { value: 2 }, 1)
+student@ubuntu:~/[[ROOT]]/test$
+```
+
+### Notions
+
+- https://doc.bccnsoft.com/docs/rust-1.36.0-docs-html/std/ops/trait.Drop.html
+- https://doc.rust-lang.org/std/cell/struct.RefCell.html
+- https://doc.rust-lang.org/book/ch15-05-interior-mutability.html
diff --git a/subjects/error_type/README.md b/subjects/error_type/README.md
new file mode 100644
index 00000000..1c86b25f
--- /dev/null
+++ b/subjects/error_type/README.md
@@ -0,0 +1,124 @@
+## error types
+
+### Instructions
+
+For this exercise you will have to implement an **error type**.
+
+The main objective is to create a form validator, where you must implement a
+error type. This must validate the password and the first name. The
+first name must not be empty and the password must have at least 8 char and a combination of alphanumeric and none alphanumeric ASCII characters
+
+ex: "asDd123=%" => good
+    "asgfD"     => error
+    "asdsdf2"   => error
+    "sad_#$"    => error
+
+Create a structure called `Form` that will have the following fields:
+
+- `first_name`, that will be a string
+- `last_name`, that will be a string
+- `birth`, of type `NaiveDate` that will convert a string "2015-09-05" to a date of that format
+- `sex`, SexType that must be a `enum` with the fields `Male` and `Female`
+- `birth_location`, that will be a string
+- `password`, that will be a string
+
+You must also implement for this structure a function to initialize the structure, `new` and a function called
+`validate` that will validate the form
+
+For the error type you must create a type struct called `FErr`, that will be the type for the error
+It must have the fields:
+
+- `form_values`, this will be a tuple of strings that will save the value that the user inserted into the form
+
+ex: ("password", "asdaSD_")
+    ("first_name", "someone")
+
+- `date`, that will have the date that the error occurred in the format "2020-12-14 09:33:41"
+- `err`, that will have the error description:
+  - "No user name"
+  - "At least 8 characters"
+  - "Combination of different ASCII character types (numbers, letters and none alphanumeric characters)"
+
+### Expected Function
+
+```rust
+pub use chrono::{Utc, NaiveDate};
+
+// this will be the structure that wil handle the errors
+#[derive(Debug, Eq, PartialEq)]
+pub struct FErr {
+    // expected public fields
+}
+impl FErr {
+    pub fn new(name: String, error: String, err: String) -> FErr {}
+}
+
+#[derive(Debug, Eq, PartialEq)]
+pub enum SexType {
+    // expected public fields
+}
+#[derive(Debug, Eq, PartialEq)]
+pub struct Form {
+    // expected public fields
+}
+
+impl Form {
+    pub fn new(first_name: String,
+           last_name: String,
+           birth: NaiveDate,
+           sex: SexType,
+           birth_location: String,
+           password: String) -> Form {}
+    pub fn validate(&self) -> Result<Vec<&str>, FErr> {}
+}
+```
+
+### Usage
+
+Here is a program to test your function
+
+```rust
+fn main() {
+    let mut form_output = Form::new(
+        String::from("Alice"),
+        String::from("Bear"),
+        create_date("2015-09-05"),
+        SexType::Male,
+        String::from("Africa"),
+        String::from("qwqwsa1dty_"));
+
+    println!("{:?}", form_output);
+    println!("{:?}", form_output.validate().unwrap());
+
+    form_output.first_name = String::from("");
+    println!("{:?}", form_output.validate().unwrap_err());
+
+    form_output.first_name = String::from("as");
+    form_output.password = String::from("dty_1");
+    println!("{:?}", form_output.validate().unwrap_err());
+
+    form_output.password = String::from("asdasASd(_");
+    println!("{:?}", form_output.validate().unwrap_err());
+
+    form_output.password = String::from("asdasASd123SA");
+    println!("{:?}", form_output.validate().unwrap_err());
+}
+```
+
+And its output:
+
+```console
+student@ubuntu:~/[[ROOT]]/test$ cargo run
+Form { first_name: "Lee", last_name: "Silva", birth: 2015-09-05, sex: Male, birth_location: "Africa", password: "qwqwsa1dty_" }
+["Valid first name", "Valid password"]
+FErr { form_values: ("first_name", ""), date: "2020-12-28 13:29:11", err: "No user name" }
+FErr { form_values: ("password", "dty_1"), date: "2020-12-28 13:29:11", err: "At least 8 characters" }
+FErr { form_values: ("password", "asdasASd(_"), date: "2020-12-28 13:29:11", err: "Combination of different ASCII character types (numbers, letters and none alphanumeric characters)" }
+FErr { form_values: ("password", "asdasASd123SA"), date: "2020-12-28 13:29:11", err: "Combination of different ASCII character types (numbers, letters and none alphanumeric characters)" }
+student@ubuntu:~/[[ROOT]]/test$
+```
+
+### Notions
+
+- https://doc.rust-lang.org/rust-by-example/error/multiple_error_types/define_error_type.html
+- https://docs.rs/chrono/0.4.19/chrono/naive/struct.NaiveDate.html
diff --git a/subjects/handling/README.md b/subjects/handling/README.md
new file mode 100644
index 00000000..9e13f696
--- /dev/null
+++ b/subjects/handling/README.md
@@ -0,0 +1,48 @@
+## handling
+
+### Instructions
+
+Write a function, called `open_or_create` that as two arguments:
+
+- `file : &str` which is the name of the files
+- `content: &str` being the content to be written into the file
+
+This functions should try to open a file, if it does not exist creates it.
+You should panic, with the error, in case something goes wrong.
+
+### Expected Function
+
+```rust
+pub fn open_or_create(s: &str, content: &str) {}
+```
+
+### Usage
+
+Here is a program to test your function
+
+```rust
+fn main() {
+    let path = "a.txt";
+    File::create(path).unwrap();
+    open_or_create(path, "content to be written");
+
+    let mut file = File::open(path).unwrap();
+
+    let mut s = String::new();
+    file.read_to_string(&mut s).unwrap();
+    println!("{}", s);
+}
+```
+
+And its output:
+
+```console
+student@ubuntu:~/[[ROOT]]/test$ cargo run
+content to be written
+student@ubuntu:~/[[ROOT]]/test$
+```
+
+### Notions
+
+- https://doc.rust-lang.org/std/io/enum.ErrorKind.html
+- https://doc.rust-lang.org/std/fs/struct.File.html
diff --git a/subjects/how_many_references/README.md b/subjects/how_many_references/README.md
new file mode 100644
index 00000000..57815632
--- /dev/null
+++ b/subjects/how_many_references/README.md
@@ -0,0 +1,78 @@
+## how many references
+
+### Instructions
+
+Create the following functions :
+
+- `add_ele` that adds an element to the value in the `Node`
+- `how_many_references` that returns how many times the value is referenced in the code
+- `rm_all_ref` that receives a `Rc<String>` and removes all elements from the vector that
+  are equal to that value, this should only happen if the two Rcs point to the same allocation
+
+### Expected Function
+
+```rust
+pub use std::rc::Rc;
+
+pub struct Node {
+    pub value: Vec<Rc<String>>,
+}
+
+impl Node {
+    pub fn new(value: Vec<Rc<String>>) -> Node {
+        Node { value: value }
+    }
+    pub fn add_ele(&mut self, v: Rc<String>) {}
+    pub fn rm_all_ref(&mut self, v: Rc<String>) {}
+}
+
+pub fn how_many_references(value: &Rc<String>) -> usize {}
+```
+
+### Usage
+
+Here is a program to test your function
+
+```rust
+fn main() {
+    let a = Rc::new(String::from("a"));
+    let b = Rc::new(String::from("b"));
+    let c = Rc::new(String::from("c"));
+
+    let a1 = Rc::new(String::from("a"));
+
+    let mut new_node = Node::new(vec![a.clone()]);
+    new_node.add_ele(b.clone());
+    new_node.add_ele(a.clone());
+    new_node.add_ele(c.clone());
+    new_node.add_ele(a.clone());
+
+    println!("a: {:?}", how_many_references(&a));
+    println!("b: {:?}", how_many_references(&b));
+    println!("c: {:?}", how_many_references(&c));
+    new_node.rm_all_ref(a1.clone());
+    new_node.rm_all_ref(a.clone());
+
+    println!("a: {:?}", how_many_references(&a));
+    println!("b: {:?}", how_many_references(&b));
+    println!("c: {:?}", how_many_references(&c));
+}
+```
+
+And its output:
+
+```console
+student@ubuntu:~/[[ROOT]]/test$ cargo run
+a: 4
+b: 2
+c: 2
+a: 1
+b: 2
+c: 2
+student@ubuntu:~/[[ROOT]]/test$
+```
+
+### Notions
+
+- https://doc.rust-lang.org/book/ch15-04-rc.html
+- https://doc.rust-lang.org/std/rc/struct.Rc.html
diff --git a/subjects/panic/README.md b/subjects/panic/README.md
new file mode 100644
index 00000000..cb24962c
--- /dev/null
+++ b/subjects/panic/README.md
@@ -0,0 +1,34 @@
+## panic
+
+### Instructions
+
+Write a function that tries to open a file and panics if the file
+doesn't exist
+
+### Expected Function
+
+```rust
+pub fn open_file(s: &str) -> File {}
+```
+
+### Usage
+
+Here is a program to test your function
+
+```rust
+fn main() {
+    let filename = "created.txt";
+    File::create(filename).unwrap();
+    let a = open_file(filename);
+    println!("{:?}", a);
+    fs::remove_file(filename).unwrap();
+}
+```
+
+And its output:
+
+```console
+student@ubuntu:~/[[ROOT]]/test$ cargo run
+File { fd: 3, path: "[[ROOT]]/a.txt", read: true, write: false }
+student@ubuntu:~/[[ROOT]]/test$
+```
diff --git a/subjects/profanity_filter/README.md b/subjects/profanity_filter/README.md
new file mode 100644
index 00000000..fd96b59d
--- /dev/null
+++ b/subjects/profanity_filter/README.md
@@ -0,0 +1,81 @@
+## profanity filter
+
+### Instructions
+
+Sometimes it is more desirable to catch the failure of some parts of a program instead
+of just calling panic.
+
+For this exercise you will have to create a message blocker, where you must block the word `stupid`
+
+You will have to create a structure called `Message`, this structure
+must have the following elements:
+
+- content: String
+- user: String
+- time_sent: String
+
+The struct must also have a implementation of 2 functions associated to it:
+
+- `new`, that initializes the structure
+- `send_ms`, that only has its implementation type (**self**) as argument and returns an option.
+  This function must return `None` if the content of the message is either **empty** or contains the
+  word **stupid**. Otherwise it returns the content of the message.
+
+You will have to create two more functions that aren't associated to any structure:
+
+- `check_ms` that receives as parameters the reference to the structure `Message` and returns a tuple,
+containing a `bool` and a `string`. This function will execute the function `send_ms` and if the result
+of the option is `None` it should return (false, "ERROR: illegal"). Otherwise it returns `true` and the
+content of the message sent.
+- `date_format` that creates and formats the date and time that the message was sent, the format should
+look like this: **Mon Oct  5 10:22:19 2020**
+
+### Expected Function
+
+```rust
+pub struct Message {}
+
+impl Message {
+  pub fn new(ms: String, u: String, t: String) -> Message {}
+  pub fn send_ms(&self) -> Option<&str> {}
+}
+
+pub fn check_ms(ms: &Message) -> (bool, &str) {}
+pub fn format_date() -> String {}
+```
+
+### Usage
+
+Here is a program to test your function
+
+```rust
+fn main() {
+  let m0 = Message::new("hello there".to_string(), "toby".to_string(), format_date());
+  println!("{:?}", check_ms(&m0));
+
+  let m1 = Message::new("".to_string(), "toby".to_string(), format_date());
+  println!("{:?}", check_ms(&m1));
+
+  let m2 = Message::new("you are stupid".to_string(), "toby".to_string(), format_date());
+  println!("{:?}", check_ms(&m2));
+
+  let m3 = Message::new("stupid".to_string(), "toby".to_string(), format_date());
+  println!("{:?}", check_ms(&m3));
+}
+```
+
+And its output:
+
+```console
+student@ubuntu:~/[[ROOT]]/test$ cargo run
+(true, "hello there")
+(false, "ERROR: illegal")
+(false, "ERROR: illegal")
+(false, "ERROR: illegal")
+student@ubuntu:~/[[ROOT]]/test$
+```
+
+### Notions
+
+- https://docs.rs/chrono/0.4.19/chrono/
+- https://doc.rust-lang.org/stable/book/ch06-01-defining-an-enum.html?highlight=option#the-option-enum-and-its-advantages-over-null-values
diff --git a/subjects/project_motion/README.md b/subjects/project_motion/README.md
new file mode 100644
index 00000000..dbf21ae2
--- /dev/null
+++ b/subjects/project_motion/README.md
@@ -0,0 +1,70 @@
+## project_motion
+
+### Instructions
+
+For this exercise you will have to create a [projectile motion](https://cimg2.ck12.org/datastreams/f-d%3Abb024be6673110b31e78b46819e792adaed8dc661e082a61f0a6d64e%2BIMAGE%2BIMAGE.1).
+
+You will be provided with a structure called `Object` that will have all variables that are
+essential for the projectile physics. (distance, velocity, height, time)
+
+You must implement :
+
+- A function `throw_object` that will initialize the Object with a given velocity and height.
+- The trait Iterator with the `.next()` in which it must calculate the next position of the object after 1 second.
+  It will return an `Option` with the Object, It will return `None` if the object already reached the floor.
+
+### Expected Function
+
+```rust
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct Object {
+    pub distance: f32,
+    pub velocity: f32,
+    pub height: f32,
+    pub time: f32,
+}
+
+impl Object {
+    pub fn throw_object(velocity: f32, height: f32) -> Object {}
+}
+
+impl Iterator for Object {
+  // next
+}
+
+```
+
+### Usage
+
+Here is a program to test your function
+
+```rust
+fn main() {
+    let mut obj = Object::throw_object(50.0, 150.0);
+    println!("{:?}", obj.next());
+    println!("{:?}", obj.next());
+    println!("{:?}", obj.next());
+    println!("{:?}", obj.next());
+    println!("{:?}", obj.next());
+    println!("{:?}", obj.next());
+}
+```
+
+And its output:
+
+```console
+student@ubuntu:~/[[ROOT]]/test$ cargo run
+Some(Object { distance: 50.0, velocity: 50.0, height: 145.1, time: 1.0 })
+Some(Object { distance: 100.0, velocity: 50.0, height: 125.5, time: 2.0 })
+Some(Object { distance: 150.0, velocity: 50.0, height: 81.4, time: 3.0 })
+Some(Object { distance: 200.0, velocity: 50.0, height: 3.0, time: 4.0 })
+None
+None
+student@ubuntu:~/[[ROOT]]/test$
+```
+
+### Notions
+
+- https://doc.rust-lang.org/std/iter/trait.Iterator.html
+- https://doc.rust-lang.org/rust-by-example/trait/iter.html
diff --git a/subjects/question_mark/README.md b/subjects/question_mark/README.md
new file mode 100644
index 00000000..8839639a
--- /dev/null
+++ b/subjects/question_mark/README.md
@@ -0,0 +1,70 @@
+## question_mark
+
+### Instructions
+
+You will have to create 3 structures:
+
+- `One`, that contains one element called `first_layer` it should be an `Option` for the structure `Two`.
+- `Two`, that contains one element called `second_layer` it should be an `Option` for the structure `Three`.
+- `Three`, that contains one element called `third_layer` it should be an `Option` for the structure `Four`.
+- `Four`, that contains one element called `fourth_layer` it should be an `u16` that is an `Option`.
+
+Beside the structure you must create a function named `get_fourth_layer` that is associated to the `One` structure.
+This function should return the `Option` value in the `Four` structure.
+
+### Expected Function
+
+```rust
+pub struct One {
+    // expected public fields
+}
+pub struct Two {
+    // expected public fields
+}
+pub struct Three {
+    // expected public fields
+}
+pub struct Four {
+    // expected public fields
+}
+
+impl One {
+    pub fn get_fourth_layer(&self) -> Option<u16> {}
+}
+```
+
+### Usage
+
+Here is a program to test your function
+
+```rust
+fn main() {
+    let a = One {
+        first_layer : Some(Two {
+            second_layer: Some(Three {
+                third_layer: Some(Four {
+                    fourth_layer: Some(1000)
+                })
+            })
+        })
+    };
+
+    // output: 1000
+    println!("{:?}", match a.get_fourth_layer() {
+        Some(e) => e,
+        None => 0
+    })
+}
+```
+
+And its output:
+
+```console
+student@ubuntu:~/[[ROOT]]/test$ cargo run
+1000
+student@ubuntu:~/[[ROOT]]/test$
+```
+
+### Notions
+
+- https://doc.rust-lang.org/stable/rust-by-example/error/option_unwrap/question_mark.html
diff --git a/subjects/ref_cell/README.md b/subjects/ref_cell/README.md
new file mode 100644
index 00000000..7507201e
--- /dev/null
+++ b/subjects/ref_cell/README.md
@@ -0,0 +1,112 @@
+## ref_cell
+
+### Instructions
+
+### 1º part
+
+Create a module called `messenger`. This module will be able to inform a user of how much references of a given value he is using.
+The main objective for this module is to limit how many times a value is referenced.
+
+For the module you must create the following:
+
+- A trait `Logger` that implements three functions: `warning`, `info`, `error`. All function should receive a reference to themselves and a string literal.
+
+```rust
+    fn warning(&self, msg: &str);
+    fn info(&self, msg: &str);
+    fn error(&self, msg: &str);
+```
+
+- A structure called `Tracker`, that must have the fields: `logger` being a reference to the `Logger`, `value` being the count of how many times the value was referenced,
+  `max` being the max count of references the actual value can achieve.
+
+- An implementation of three functions that are associated to the `Tracker` structure:
+  - `new` that will initialize the structure
+  - `set_value` that sets the value to the `Tracker` structure and writes to the trait functions. This should be done comparing the **max** and the number of referenced of the actual value.
+    If the percentage is equal or greater to 100% of the limit usage, it should write **"Error: you are over your quota!"** to the `error` function
+    If the percentage is equal or greater to 70% of the limit usage, it should write **("Warning: you have used up over {}% of your quota! Proceeds with precaution", <calculated_percentage>)** to the `warning` function
+  - `peek` that will take a peek of how much usage the variable already has. It should write **("Info: you are using up too {}% of your quote", <calculated_percentage>)** to the `info` function
+
+### 2ª part
+
+Afterwards you must use the module `messenger` and create the following:
+
+- A structure `Worker` that has the fields:
+  - `track_value` this will be the value that will be tracked by the tracker.
+  - `mapped_messages` that will have the latest messages. This must be a HashMap with the key being the type of message
+  sent by the logger (info, error or warning) and the value being the message
+  - `all_messages` that will be a vector of all messages sent.
+- A `new` function that initializes the structure `Worker`
+- To use the trait `Logger` you must implement it for the Worker structure. Each function (warning, error and info) must insert the message to the
+  respective fields of the structure Worker.
+
+You must use **interior mutability**, this means it must be able to mutate data even when there are immutable references to that data.
+
+So the user doesn't need to use the keyword `mut` (tip: RefCell)
+
+### Usage
+
+Here is a program to test your function
+
+```rust
+fn main() {
+    // initialize the worker
+    let Logger = Worker::new(1);
+
+    // initialize the tracker, with the max number of
+    // called references as 10
+    let track = Tracker::new(&Logger, 10);
+
+    let _a = Logger.track_value.clone();    // |\
+    let _a1 = Logger.track_value.clone();   // | -> increase the Rc to 4 references
+    let _a2 = Logger.track_value.clone();   // |/
+
+    // take a peek of how much we already used from our quota
+    track.peek(&Logger.track_value);
+
+    let _b = Logger.track_value.clone();  // |\
+    let _b1 = Logger.track_value.clone(); // |  -> increase the Rc to 8 references
+    let _b2 = Logger.track_value.clone(); // | /
+    let _b3 = Logger.track_value.clone(); // |/
+
+    // this will set the value and making a verification of
+    // how much we already used of our quota
+    track.set_value(&Logger.track_value);
+
+    let _c = Logger.track_value.clone(); // | -> increase the Rc to 9 references
+
+    // this will set the value and making a verification of
+    // how much we already used of our quota
+    track.set_value(&Logger.track_value);
+
+    let _c1 = Logger.track_value.clone(); // | -> increase the Rc to 10 references, this will be the limit
+
+    track.set_value(&Logger.track_value);
+
+    for (k ,v) in Logger.mapped_messages.into_inner() {
+        println!("{:?}", (k ,v));
+    }
+    println!("{:?}", Logger.all_messages.into_inner());
+}
+```
+
+And its output:
+
+```console
+student@ubuntu:~/[[ROOT]]/test$ cargo run
+("Info", "you are using up too 40% of your quote")
+("Warning", "you have used up over 90% of your quota! Proceeds with precaution")
+("Error", "you are over your quota!")
+[
+  "Info: you are using up too 40% of your quote",
+  "Warning: you have used up over 80% of your quota! Proceeds with precaution",
+  "Warning: you have used up over 90% of your quota! Proceeds with precaution",
+  "Error: you are over your quota!"
+]
+student@ubuntu:~/[[ROOT]]/test$
+```
+
+### Notions
+
+- https://doc.rust-lang.org/std/cell/struct.RefCell.html
+- https://doc.rust-lang.org/std/rc/struct.Rc.html
diff --git a/subjects/sales/README.md b/subjects/sales/README.md
new file mode 100644
index 00000000..477e5f59
--- /dev/null
+++ b/subjects/sales/README.md
@@ -0,0 +1,101 @@
+## sales
+
+### Instructions
+
+You will have to create a shopping system, where you will have a :
+
+- Store that will save all the products in it
+- Cart that will have `items`, that the client will buy, and a `receipt`
+
+This store is having a promotion, "Buy three and get one for free" (the free item must be the cheapest). The receipt must not present
+any value as 0, so you will have to apply the promotion to all items instead.
+
+### Expected Function
+
+```rust
+
+#[derive(Debug, Clone)]
+pub struct Store {
+    pub products: Vec<(String, f32)>,
+}
+impl Store {
+    pub fn new(products: Vec<(String, f32)>) -> Store {
+        Store { products }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct Cart {
+    // expected public fields
+}
+impl Cart {
+    pub fn new() -> Cart {}
+    pub fn insert_item(&mut self, s: &Store, ele: String) {}
+    pub fn get_prices(&self) -> Vec<f32> {}
+    pub fn generate_receipt(&mut self) -> Vec<f32> {}
+}
+
+```
+
+### Example
+
+`[1.23, 3.12, 23.1]` -> receipt will be `[1.17, 2.98, 22.07]`
+
+So `1.17 + 2.98 + 22.07 == 3.12 + 23.1 + 0`
+
+This is a percentage calculation, and it can be applied to a set of three items.
+If the client purchase 9 items it will be applied the promotion, three for free, to all items
+
+|--------------|  |---------------|  |---------------|
+`[1.23, 23.1, 3.12, 9.75, 1.75, 23.75, 2.75, 1.64, 15.23]` -> receipt will be `[1.16, 1.55, 1.65, 2.6, 2.94, 9.2, 14.38, 21.8, 22.42]`
+
+|--------|  |--------|   |--------|
+`[3.12, 9.75, 1.75, 23.75, 2.75, 1.64, 15.23]` -> receipt will be `[1.54, 1.65, 2.59, 2.94, 9.18, 14.34, 22.36]`
+
+and so on... (hint: Closures is the way)
+
+You will have to implement for the Cart structure the following function:
+
+- `new`, that will initialize the cart
+- `insert_item`, that will receive a reference to `Store` and a `String`. Just like the name says you will
+  have to insert the item to the cart
+- `generate_receipt`, that returns a vector of sorted floats. This function must generate the receipt just
+like the example above, using the promotion. Also saving the result in the filed `receipt`.
+
+### Usage
+
+Here is a program to test your function
+
+```rust
+fn main() {
+    let store = Store::new(vec![
+        (String::from("product A"), 1.23),
+        (String::from("product B"), 23.1),
+        (String::from("product C"), 3.12)]);
+
+    println!("{:?}", store);
+
+    let mut cart = Cart::new();
+    cart.insert_item(&store, String::from("product A"));
+    cart.insert_item(&store, String::from("product B"));
+    cart.insert_item(&store, String::from("product C"));
+
+    println!("{:?}", cart.generate_receipt());
+
+    println!("{:?}", cart);
+}
+```
+
+And its output:
+
+```console
+student@ubuntu:~/[[ROOT]]/test$ cargo run
+Store { products: [("product A", 1.23), ("product B", 23.1), ("product C", 3.12)] }
+[1.17, 2.98, 22.07]
+Cart { items: [("product A", 1.23), ("product B", 23.1), ("product C", 3.12)], receipt: [1.17, 2.98, 22.07] }
+student@ubuntu:~/[[ROOT]]/test$
+```
+
+### Notions
+
+- https://doc.rust-lang.org/rust-by-example/fn/closures.html
diff --git a/subjects/unwrap_or_expect/README.md b/subjects/unwrap_or_expect/README.md
new file mode 100644
index 00000000..249a3caa
--- /dev/null
+++ b/subjects/unwrap_or_expect/README.md
@@ -0,0 +1,66 @@
+## unwrap
+
+### Instructions
+
+It will be given a function called **odd_to_even**, that returns an `Result`. If its an error it will
+return a tuple with a string, indicating the error, and a vector with the elements that justifies the error
+
+The objective is to execute the `odd_to_even` function and handle the error given by it
+
+Create the following functions that receives a vector :
+
+- `expect` that returns the error adding the sting "ERROR "
+- `unwrap_or` that in case of error returns an empty vector
+- `unwrap_err` that returns error if its `Ok` and returns the
+   string containing the error in case of `Err`
+- `unwrap` that unwraps the `Result`
+- `unwrap_or_else` that in case of error returns a the vector that justifies the error
+
+### Expected Function
+
+```rust
+pub fn odd_to_even(data: Vec<u32>) -> Result<Vec<u32>, (String, Vec<u32>)> {}
+pub fn expect(v: Vec<u32>) -> Vec<u32> {}
+pub fn unwrap_or(v: Vec<u32>) -> Vec<u32> {}
+pub fn unwrap_err(v: Vec<u32>) -> (String, Vec<u32>) {}
+pub fn unwrap(v: Vec<u32>) -> Vec<u32> {}
+pub fn unwrap_or_else(v: Vec<u32>) -> Vec<u32> {}
+```
+
+### Usage
+
+Here is a program to test your function
+
+```rust
+fn main() {
+    // this will give an expect error
+    // println!("{:?}", expect(vec![1, 3, 2, 5]));
+    println!("{:?}", unwrap_or(vec![1, 3, 2, 5]));
+    println!("{:?}", unwrap_or(vec![1, 3, 5]));
+    println!("{:?}", unwrap_err(vec![1, 3, 2, 5]));
+    // this will give an error that is unwraped
+    // println!("{:?}", unwrap_err(vec![1, 3, 5]));
+    println!("{:?}", unwrap(vec![1, 3, 5]));
+    // this will give an error
+    // println!("{:?}", unwrap(vec![1, 3, 2, 5]));
+    println!("{:?}", unwrap_or_else(vec![1, 3, 5]));
+    println!("{:?}", unwrap_or_else(vec![3, 2, 6, 5]));
+}
+```
+
+And its output:
+
+```console
+student@ubuntu:~/[[ROOT]]/test$ cargo run
+[]
+[2, 4, 6]
+("There is a even value in the vector!", [2])
+[2, 4, 6]
+[2, 4, 6]
+[2, 6]
+student@ubuntu:~/[[ROOT]]/test$
+```
+
+### Notions
+
+- https://doc.rust-lang.org/std/?search=unwrap