diff --git a/puppeteer/mouse-trap.js b/puppeteer/mouse-trap.js
index 4a872d814..c888a3d83 100644
--- a/puppeteer/mouse-trap.js
+++ b/puppeteer/mouse-trap.js
@@ -20,14 +20,15 @@ export const createCircle = () => {
 }
 
 const create = ({ clientX, clientY }) => {
-  const elem = document.createElement('div')
-  elem.className = 'elem'
-  body.append(elem)
-  elem.style.top = `${clientY - radius}px`
-  elem.style.left = `${clientX - radius}px`
+  const circle = document.createElement('div')
+  circle.className = 'circle'
+  body.append(circle)
+  circle.style.top = `${clientY - radius}px`
+  circle.style.left = `${clientX - radius}px`
+  circle.style.background = 'white'
   const hasEntered = insideX(clientX) && insideY(clientY)
   if (hasEntered) {
-    elem.style.background = 'var(--purple)'
+    circle.style.background = 'var(--purple)'
   }
   isInside = false
 }
@@ -38,29 +39,29 @@ export const moveCircle = () => {
 }
 
 const move = (e) => {
-  const elems = [...document.getElementsByClassName('elem')]
-  const elem = elems[elems.length - 1]
-  if (!elem) return
-  position(e, elem)
+  const circles = [...document.getElementsByClassName('circle')]
+  const circle = circles[circles.length - 1]
+  if (!circle) return
+  position(e, circle)
 }
 
-const position = ({ clientX, clientY }, elem) => {
+const position = ({ clientX, clientY }, circle) => {
   const hasEntered = insideX(clientX) && insideY(clientY)
 
   if (hasEntered) {
     isInside = true
-    elem.style.background = 'var(--purple)'
+    circle.style.background = 'var(--purple)'
   }
 
   if (isInside) {
     if (insideY(clientY)) {
-      elem.style.top = `${clientY - radius}px`
+      circle.style.top = `${clientY - radius}px`
     }
     if (insideX(clientX)) {
-      elem.style.left = `${clientX - radius}px`
+      circle.style.left = `${clientX - radius}px`
     }
   } else {
-    elem.style.top = `${clientY - radius}px`
-    elem.style.left = `${clientX - radius}px`
+    circle.style.top = `${clientY - radius}px`
+    circle.style.left = `${clientX - radius}px`
   }
 }
diff --git a/puppeteer/mouse-trap_test.js b/puppeteer/mouse-trap_test.js
new file mode 100644
index 000000000..a32c7a303
--- /dev/null
+++ b/puppeteer/mouse-trap_test.js
@@ -0,0 +1,123 @@
+export const tests = []
+
+export const setup = async ({ page }) => {
+  return {
+    getCirclesPos: async () =>
+      await page.$$eval('.circle', (nodes) => {
+        const circleRadius = 25
+        const formatPos = (pos) => Number(pos.replace('px', '')) + circleRadius
+        return nodes.map((node) => [
+          formatPos(node.style.left),
+          formatPos(node.style.top),
+        ])
+      }),
+  }
+}
+
+tests.push(async ({ page, viewport, eq, getCirclesPos }) => {
+  // check that a circle is created on click at the mouse position
+  const { width, height } = await page.evaluate(() => ({
+    width: document.documentElement.clientWidth,
+    height: document.documentElement.clientHeight,
+  }))
+
+  const clicks = [...Array(10).keys()].map((e) => [
+    random(width),
+    random(height),
+  ])
+
+  for (const [i, click] of clicks.entries()) {
+    const [posX, posY] = click
+    await page.mouse.click(posX, posY)
+    const currentCircle = (await getCirclesPos())[i]
+    eq(currentCircle, click)
+  }
+})
+
+tests.push(async ({ page, eq, getCirclesPos }) => {
+  // check that the last created circle moves along the mouse
+  let move = 0
+  while (move < 100) {
+    move += 1
+    const x = move
+    const y = move * 2
+    await page.mouse.move(x, y)
+    const circles = await getCirclesPos()
+    const currentCirclePos = circles[circles.length - 1]
+    eq(currentCirclePos, [x, y])
+  }
+})
+
+tests.push(async ({ page, eq, getCirclesPos }) => {
+  // check that a circle is trapped and purple when inside the box
+  const box = await page.$eval('.box', (box) => ({
+    top: box.getBoundingClientRect().top,
+    right: box.getBoundingClientRect().right,
+    left: box.getBoundingClientRect().left,
+    bottom: box.getBoundingClientRect().bottom,
+  }))
+
+  await page.mouse.click(200, 200)
+
+  let move = 200
+  let hasEntered = false
+
+  while (move < 500) {
+    const x = move + 50
+    const y = move
+    await page.mouse.move(x, y)
+
+    const circles = await getCirclesPos()
+    const currentCircle = circles[circles.length - 1]
+
+    const circleRadius = 25
+
+    const bg = await page.$$eval(
+      '.circle',
+      (nodes) => nodes[nodes.length - 1].style.background,
+    )
+
+    const insideX = x > box.left + circleRadius && x < box.right - circleRadius
+    const insideY = y > box.top + circleRadius && y < box.bottom - circleRadius
+    const isInside = insideX && insideY
+
+    // check that the background is set to the right color
+    if (isInside) {
+      hasEntered = true
+      eq(bg, 'var(--purple)')
+    } else {
+      eq(bg, hasEntered ? 'var(--purple)' : 'white')
+    }
+
+    // check that the mouse is trapped inside the box
+    if (hasEntered) {
+      if (insideY) {
+        eq(currentCircle[1], y)
+      } else {
+        const maxY =
+          currentCircle[1] === box.top + circleRadius + 1 ||
+          currentCircle[1] === box.bottom - circleRadius - 1
+        eq(maxY, true)
+      }
+      if (insideX) {
+        eq(currentCircle[0], x)
+      } else {
+        const maxX =
+          currentCircle[0] === box.left + circleRadius + 1 ||
+          currentCircle[0] === box.right - circleRadius - 1
+        eq(maxX, true)
+      }
+    }
+    move++
+  }
+})
+
+const random = (min, max) => {
+  if (!max) {
+    max = min
+    min = 0
+  }
+  min = Math.ceil(min)
+  max = Math.floor(max)
+  return Math.floor(Math.random() * (max - min + 1)) + min
+}
diff --git a/subjects/mouse-trap/README.md b/subjects/mouse-trap/README.md
index f6b32493e..5b613d08b 100644
--- a/subjects/mouse-trap/README.md
+++ b/subjects/mouse-trap/README.md
@@ -4,7 +4,7 @@
 
 Develop a trap to capture the elements when the mouse is getting too close to the center of the page!
 
-- Create a function `createCircle`: make it fire on every click on the page, and create a white circle at the position of the mouse on the screen
+- Create a function `createCircle`: make it fire on every click on the page, and create a `div` at the position of the mouse on the screen, setting its `background` to `white` and its class to `circle`
 
 - Create a function `moveCircle`: make it fire when the mouse moves, and get the last circle created and makes it move along with the mouse
 
diff --git a/subjects/mouse-trap/index.html b/subjects/mouse-trap/index.html
index c59f1185a..90ca014c1 100644
--- a/subjects/mouse-trap/index.html
+++ b/subjects/mouse-trap/index.html
@@ -33,11 +33,10 @@ body {
   font-size: 12px;
 }
 
-.elem {
+.circle {
   width: 50px;
   height: 50px;
   border-radius: 50%;
-  background: var(--clear);
   position: absolute;
   opacity: 0.75;
 }