diff --git a/go/tests/cat_test/cat_correct/main.go b/go/tests/cat_test/cat_correct/main.go
index 04d0a21a..6c64a22c 100644
--- a/go/tests/cat_test/cat_correct/main.go
+++ b/go/tests/cat_test/cat_correct/main.go
@@ -4,6 +4,8 @@ import (
 	"io"
 	"io/ioutil"
 	"os"
+
+	"lib"
 )
 
 func main() {
@@ -13,11 +15,11 @@ func main() {
 		}
 	} else {
 		for _, arg := range os.Args[1:] {
-			data, err := ioutil.ReadFile(arg)
+			b, err := ioutil.ReadFile(arg)
 			if err != nil {
-				panic(err)
+				lib.Fatalln("ERROR:", err)
 			}
-			os.Stdout.Write(data)
+			os.Stdout.Write(b)
 		}
 	}
 }
diff --git a/go/tests/cat_test/main.go b/go/tests/cat_test/main.go
index a99f6efc..929ce624 100644
--- a/go/tests/cat_test/main.go
+++ b/go/tests/cat_test/main.go
@@ -3,74 +3,25 @@ package main
 import (
 	"io/ioutil"
 	"os"
-	"os/exec"
 	"strings"
 
-	"github.com/01-edu/public/go/lib"
+	"lib"
 )
 
 func main() {
-	pathFileName1 := "./student/cat/quest8.txt"
-	pathFileName2 := "./student/cat/quest8T.txt"
-
-	if _, err := os.Stat(pathFileName1); err != nil {
-		lib.Fatalln(err)
+	file1 := "quest8.txt"
+	file2 := "quest8T.txt"
+	if err := ioutil.WriteFile(file1, []byte(lib.RandWords()+"\n"), os.ModePerm); err != nil {
+		panic(err)
 	}
-	if _, err := os.Stat(pathFileName2); err != nil {
-		lib.Fatalln(err)
+	if err := ioutil.WriteFile(file2, []byte(lib.RandWords()+"\n"), os.ModePerm); err != nil {
+		panic(err)
 	}
-	table := []string{pathFileName1, pathFileName1 + " " + pathFileName2, "asd"}
+
+	table := []string{file1, file1 + " " + file2, "asd", "", file1 + " abc", "abc " + file2}
 
 	for _, s := range table {
 		lib.ChallengeMain("cat", strings.Fields(s)...)
 	}
-	if _, err := exec.Command("go", "build", "-o", "cat_student", "./student/cat/main.go").Output(); err != nil {
-		lib.Fatal(string(err.(*exec.ExitError).Stderr))
-	}
-	if _, err := exec.Command("go", "build", "-o", "cat_solution", "./solutions/cat/main.go").Output(); err != nil {
-		lib.Fatal(string(err.(*exec.ExitError).Stderr))
-	}
-	pwd, err := os.Getwd()
-	if err != nil {
-		lib.Fatalln(err)
-	}
-
-	for i := 0; i < 2; i++ {
-		randStdin := lib.RandAlnum()
-		cmd := exec.Command("sh", "-c", pwd+"/cat_solution")
-		solutionResult := execStdin(cmd, randStdin)
-		cmdS := exec.Command(pwd + "/cat_student")
-		studentResult := execStdin(cmdS, randStdin)
-
-		if solutionResult != studentResult {
-			lib.Fatalf("./cat prints %s instead of %s\n", studentResult, solutionResult)
-		}
-	}
+	lib.ChallengeMainStdin("cat", lib.RandWords()+"\n")
 }
-
-func execStdin(cmd *exec.Cmd, randomStdin string) string {
-	stdin, err := cmd.StdinPipe()
-	if err != nil {
-		lib.Fatalln(err)
-	}
-	stdout, err := cmd.StdoutPipe()
-	if err != nil {
-		lib.Fatalln(err)
-	}
-	if err := cmd.Start(); err != nil {
-		lib.Fatalln(err)
-	}
-	_, err = stdin.Write([]byte(randomStdin))
-	if err != nil {
-		lib.Fatalln(err)
-	}
-	stdin.Close()
-
-	out, _ := ioutil.ReadAll(stdout)
-	if err := cmd.Wait(); err != nil {
-		lib.Fatalln(err)
-	}
-	return string(out)
-}
-
-// TODO: handle stdin in ChallengeMain
diff --git a/subjects/cat.en.md b/subjects/cat.en.md
index 6b7d05bd..951eaa48 100644
--- a/subjects/cat.en.md
+++ b/subjects/cat.en.md
@@ -6,7 +6,7 @@ Write a program that behaves like a simplified `cat` command.
 
 - The options do not have to be handled.
 
-- If the program is called without arguments it should take the standard input (stdin) and print it back (as shown with the "Hello" example below).
+- If the program is called without arguments it should take the standard input (stdin) and print it back on the standard output (stdout).
 
 ```console
 student@ubuntu:~/[[ROOT]]/cat$ echo '"Programming is a skill best acquired by practice and example rather than from books" by Alan Turing' > quest8.txt
@@ -18,6 +18,9 @@ student@ubuntu:~/[[ROOT]]/cat$ ./cat abc
 ERROR: abc: No such file or directory
 student@ubuntu:~/[[ROOT]]/cat$ ./cat quest8.txt
 "Programming is a skill best acquired by pratice and example rather than from books" by Alan Turing
+student@ubuntu:~/[[ROOT]]/cat$ ./cat quest8.txt abc
+"Programming is a skill best acquired by pratice and example rather than from books" by Alan Turing
+ERROR: abc: No such file or directory
 student@ubuntu:~/[[ROOT]]/cat$ cat quest8.txt | ./cat
 "Programming is a skill best acquired by pratice and example rather than from books" by Alan Turing
 student@ubuntu:~/[[ROOT]]/cat$ ./cat