diff --git a/dom/action-reaction_test.js b/dom/action-reaction_test.js
new file mode 100644
index 00000000..182a1f86
--- /dev/null
+++ b/dom/action-reaction_test.js
@@ -0,0 +1,25 @@
+export const tests = []
+
+tests.push(async ({ eq, page }) => {
+  // check the initial class name of the eye left
+  const eyeLeft = await page.$eval('#eye-left', (node) => node.className)
+  eq(eyeLeft, 'eye')
+})
+
+tests.push(async ({ eq, page }) => {
+  // click the button to close the left eye
+  const button = await page.$('button')
+  button.click()
+  await page.waitForTimeout(150)
+  const eyeLeft = await page.$eval('#eye-left', (node) => node.className)
+  eq(eyeLeft, 'eye eye-closed')
+})
+
+tests.push(async ({ eq, page }) => {
+  // click the button a second time to open the left eye
+  const button = await page.$('button')
+  button.click()
+  await page.waitForTimeout(150)
+  const eyeLeft = await page.$eval('#eye-left', (node) => node.className)
+  eq(eyeLeft, 'eye')
+})