Merge branch 'justin_ho-update-testing-style-guide-with-new-extended-wrappers' into 'master'

Update docs with newest recommendations on writing specs

See merge request gitlab-org/gitlab!62996

doc/development/fe_guide/graphql.md

@@ -1097,7 +1097,7 @@ it('renders a loading state', () => {
   const mockApollo = createMockApolloProvider();
   const wrapper = createComponent({ mockApollo });
 
-  expect(wrapper.find(LoadingSpinner).exists()).toBe(true)
+  expect(wrapper.findComponent(LoadingSpinner).exists()).toBe(true)
 });
 
 it('renders designs list', async () => {
@@ -1399,7 +1399,6 @@ describe('My Index test with `createMockApollo`', () => {
 
   afterEach(() => {
     wrapper.destroy();
-    wrapper = null;
     fetchLocalUserSpy = null;
   });
 

doc/development/fe_guide/style/vue.md

@@ -463,7 +463,7 @@ Creating a global, mutable wrapper provides a number of advantages, including th
     let wrapper;
 
     // this can now be reused across tests
-    const findMyComponent = wrapper.find(MyComponent);
+    const findMyComponent = wrapper.findComponent(MyComponent);
     // ...
   })
   ```
@@ -565,16 +565,15 @@ the mounting function (`mount` or `shallowMount`) to be used to mount the compon
     function createComponent({ mountFn = shallowMount } = {}) { }
     ```
 
-1. Wrap calls to `mount` and `shallowMount` in `extendedWrapper`, this exposes `wrapper.findByTestId()`:
+1. Use the `mountExtended` and `shallowMountExtended` helpers to expose `wrapper.findByTestId()`:
 
     ```javascript
-    import { shallowMount } from '@vue/test-utils';
-    import { extendedWrapper } from 'helpers/vue_test_utils_helper';
+    import { shallowMountExtended } from 'helpers/vue_test_utils_helper';
     import { SomeComponent } from 'components/some_component.vue';
 
     let wrapper;
 
-    const createWrapper = () => { wrapper = extendedWrapper(shallowMount(SomeComponent)); };
+    const createWrapper = () => { wrapper = shallowMountExtended(SomeComponent); };
     const someButton = () => wrapper.findByTestId('someButtonTestId');
     ```
 

doc/development/fe_guide/troubleshooting.md

@@ -27,15 +27,15 @@ See [this video](https://youtu.be/-BkEhghP-kM) for an in-depth overview and inve
 **Remedy - Try cloning the object that has Vue watchers**
 
 ```patch
-- expect(wrapper.find(ChildComponent).props()).toEqual(...);
-+ expect(cloneDeep(wrapper.find(ChildComponent).props())).toEqual(...)
+- expect(wrapper.findComponent(ChildComponent).props()).toEqual(...);
++ expect(cloneDeep(wrapper.findComponent(ChildComponent).props())).toEqual(...)
 ```
 
 **Remedy - Try using `toMatchObject` instead of `toEqual`**
 
 ```patch
-- expect(wrapper.find(ChildComponent).props()).toEqual(...);
-+ expect(wrapper.find(ChildComponent).props()).toMatchObject(...);
+- expect(wrapper.findComponent(ChildComponent).props()).toEqual(...);
++ expect(wrapper.findComponent(ChildComponent).props()).toMatchObject(...);
 ```
 
 Please note that `toMatchObject` actually changes the nature of the assertion and won't fail if some items are **missing** from the expectation.

doc/development/fe_guide/vue.md

@@ -323,17 +323,13 @@ testing the rendered output.
 Here's an example of a well structured unit test for [this Vue component](#appendix---vue-component-subject-under-test):
 
 ```javascript
-import { shallowMount } from '@vue/test-utils';
-import { extendedWrapper } from 'helpers/vue_test_utils_helper';
 import { GlLoadingIcon } from '@gitlab/ui';
 import MockAdapter from 'axios-mock-adapter';
+import { shallowMountExtended } from 'helpers/vue_test_utils_helper';
 import axios from '~/lib/utils/axios_utils';
 import App from '~/todos/app.vue';
 
-const TEST_TODOS = [
-  { text: 'Lorem ipsum test text' },
-  { text: 'Lorem ipsum 2' },
-];
+const TEST_TODOS = [{ text: 'Lorem ipsum test text' }, { text: 'Lorem ipsum 2' }];
 const TEST_NEW_TODO = 'New todo title';
 const TEST_TODO_PATH = '/todos';
 
@@ -351,28 +347,27 @@ describe('~/todos/app.vue', () => {
   afterEach(() => {
     // IMPORTANT: Clean up the component instance and axios mock adapter
     wrapper.destroy();
-    wrapper = null;
-
     mock.restore();
   });
 
   // It is very helpful to separate setting up the component from
   // its collaborators (for example, Vuex and axios).
   const createWrapper = (props = {}) => {
-    wrapper = extendedWrapper(
-      shallowMount(App, {
+    wrapper = shallowMountExtended(App, {
       propsData: {
         path: TEST_TODO_PATH,
         ...props,
       },
-      })
-    );
+    });
   };
   // Helper methods greatly help test maintainability and readability.
-  const findLoader = () => wrapper.find(GlLoadingIcon);
+  const findLoader = () => wrapper.findComponent(GlLoadingIcon);
   const findAddButton = () => wrapper.findByTestId('add-button');
   const findTextInput = () => wrapper.findByTestId('text-input');
-  const findTodoData = () => wrapper.findAll('[data-testid="todo-item"]').wrappers.map(wrapper => ({ text: wrapper.text() }));
+  const findTodoData = () =>
+    wrapper
+      .findAllByTestId('todo-item')
+      .wrappers.map((item) => ({ text: item.text() }));
 
   describe('when mounted and loading', () => {
     beforeEach(() => {
@@ -401,14 +396,13 @@ describe('~/todos/app.vue', () => {
       expect(findTodoData()).toEqual(TEST_TODOS);
     });
 
-    it('when todo is added, should post new todo', () => {
-      findTextInput().vm.$emit('update', TEST_NEW_TODO)
+    it('when todo is added, should post new todo', async () => {
+      findTextInput().vm.$emit('update', TEST_NEW_TODO);
       findAddButton().vm.$emit('click');
 
-      return wrapper.vm.$nextTick()
-        .then(() => {
-          expect(mock.history.post.map(x => JSON.parse(x.data))).toEqual([{ text: TEST_NEW_TODO }]);
-        });
+      await wrapper.vm.$nextTick();
+
+      expect(mock.history.post.map((x) => JSON.parse(x.data))).toEqual([{ text: TEST_NEW_TODO }]);
     });
   });
 });

doc/development/fe_guide/vuex.md

@@ -464,7 +464,6 @@ describe('component', () => {
 
   afterEach(() => {
     wrapper.destroy();
-    wrapper = null;
   });
 
   it('should show a user', async () => {

doc/development/testing_guide/frontend_testing.md

@@ -249,7 +249,7 @@ it('exists', () => {
   wrapper.findByText(/Click Me/i)
 
   // Good (especially for unit tests)
-  wrapper.find(FooComponent);
+  wrapper.findComponent(FooComponent);
   wrapper.find('input[name=foo]');
   wrapper.find('[data-testid="my-foo-id"]');
   wrapper.findByTestId('my-foo-id'); // with shallowMountExtended or mountExtended – check below
@@ -281,7 +281,7 @@ Example:
 
 ```javascript
 it('exists', () => {
-    wrapper.find(FooComponent);
+  wrapper.findComponent(FooComponent);
 });
 ```