Added test spec for helpers/utils/debounce.js

helpers/utils/__tests__/debounce.spec.js

@@ -0,0 +1,38 @@
+import debounce from "../debounce"
+
+function sleep(millis) {
+  return new Promise((resolve) => setTimeout(resolve, millis))
+}
+
+describe("debounce", () => {
+  test("doesn't call function right after calling", () => {
+    const fn = jest.fn()
+
+    const debFunc = debounce(fn, 100)
+    debFunc()
+
+    expect(fn).not.toHaveBeenCalled()
+  })
+
+  test("calls the function after the given timeout", async () => {
+    const fn = jest.fn()
+
+    const debFunc = debounce(fn, 100)
+    debFunc()
+
+    await sleep(1000)
+
+    expect(fn).toHaveBeenCalled()
+  })
+
+  test("calls the function only one time within the timeframe", async () => {
+    const fn = jest.fn()
+
+    const debFunc = debounce(fn, 1000)
+
+    for (let i = 0; i < 100; i++) debFunc()
+    await sleep(2000)
+
+    expect(fn).toHaveBeenCalledTimes(1)
+  })
+})