From 4c1bb95651f20fa3d314554cfd320f04319a3a72 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mario=20Beltr=C3=A1n?= <belco90@gmail.com>
Date: Fri, 30 Aug 2019 10:58:25 +0200
Subject: [PATCH] First bunch of tests for lifecycle hooks blocks (#574)

* Add tests for useMount hook

* Add tests for useUnmount hook

* Add tests for useEffectOnce hook
---
 src/__tests__/useEffectOnce.test.ts | 21 +++++++++++++++++++
 src/__tests__/useMount.test.ts      | 32 +++++++++++++++++++++++++++++
 src/__tests__/useUnmount.test.ts    | 32 +++++++++++++++++++++++++++++
 3 files changed, 85 insertions(+)
 create mode 100644 src/__tests__/useEffectOnce.test.ts
 create mode 100644 src/__tests__/useMount.test.ts
 create mode 100644 src/__tests__/useUnmount.test.ts

diff --git a/src/__tests__/useEffectOnce.test.ts b/src/__tests__/useEffectOnce.test.ts
new file mode 100644
index 00000000..c7cbad89
--- /dev/null
+++ b/src/__tests__/useEffectOnce.test.ts
@@ -0,0 +1,21 @@
+import { renderHook } from '@testing-library/react-hooks';
+import { useEffectOnce } from '..';
+
+const mockEffectCleanup = jest.fn();
+const mockEffectCallback = jest.fn().mockReturnValue(mockEffectCleanup);
+
+it('should run provided effect only once', () => {
+  const { rerender } = renderHook(() => useEffectOnce(mockEffectCallback));
+  expect(mockEffectCallback).toHaveBeenCalledTimes(1);
+
+  rerender();
+  expect(mockEffectCallback).toHaveBeenCalledTimes(1);
+});
+
+it('should run clean-up provided on unmount', () => {
+  const { unmount } = renderHook(() => useEffectOnce(mockEffectCallback));
+  expect(mockEffectCleanup).not.toHaveBeenCalled();
+
+  unmount();
+  expect(mockEffectCleanup).toHaveBeenCalledTimes(1);
+});
diff --git a/src/__tests__/useMount.test.ts b/src/__tests__/useMount.test.ts
new file mode 100644
index 00000000..203f36e1
--- /dev/null
+++ b/src/__tests__/useMount.test.ts
@@ -0,0 +1,32 @@
+import { renderHook } from '@testing-library/react-hooks';
+import { useMount } from '..';
+
+const mockCallback = jest.fn();
+
+afterEach(() => {
+  jest.resetAllMocks();
+});
+
+it('should call provided callback on mount', () => {
+  renderHook(() => useMount(mockCallback));
+
+  expect(mockCallback).toHaveBeenCalledTimes(1);
+});
+
+it('should not call provided callback on unmount', () => {
+  const { unmount } = renderHook(() => useMount(mockCallback));
+  expect(mockCallback).toHaveBeenCalledTimes(1);
+
+  unmount();
+
+  expect(mockCallback).toHaveBeenCalledTimes(1);
+});
+
+it('should not call provided callback on rerender', () => {
+  const { rerender } = renderHook(() => useMount(mockCallback));
+  expect(mockCallback).toHaveBeenCalledTimes(1);
+
+  rerender();
+
+  expect(mockCallback).toHaveBeenCalledTimes(1);
+});
diff --git a/src/__tests__/useUnmount.test.ts b/src/__tests__/useUnmount.test.ts
new file mode 100644
index 00000000..ae713baa
--- /dev/null
+++ b/src/__tests__/useUnmount.test.ts
@@ -0,0 +1,32 @@
+import { renderHook } from '@testing-library/react-hooks';
+import { useUnmount } from '..';
+
+const mockCallback = jest.fn();
+
+afterEach(() => {
+  jest.resetAllMocks();
+});
+
+it('should not call provided callback on mount', () => {
+  renderHook(() => useUnmount(mockCallback));
+
+  expect(mockCallback).not.toHaveBeenCalled();
+});
+
+it('should call provided callback on unmount', () => {
+  const { unmount } = renderHook(() => useUnmount(mockCallback));
+  expect(mockCallback).not.toHaveBeenCalled();
+
+  unmount();
+
+  expect(mockCallback).toHaveBeenCalledTimes(1);
+});
+
+it('should not call provided callback on rerender', () => {
+  const { rerender } = renderHook(() => useUnmount(mockCallback));
+  expect(mockCallback).not.toHaveBeenCalled();
+
+  rerender();
+
+  expect(mockCallback).not.toHaveBeenCalled();
+});