docs(cleanup): add docs about cleanup

Author: bcarroll22

docs/api-main.md

@@ -168,8 +168,13 @@ test('renders into document', () => {
 // ... more tests ...
 ```
 
+In native-testing-library there is no DOM to cleanup, and your tests' rendered trees cannot
+interfere with each other. It is simply nice to be able to run any unmount logic in the components
+you have rendered in your tests.
+
 **If you don't want to add this to _every single test file_** then we recommend that you configure
-your test framework to run a file before your tests which does this automatically.
+your test framework to run a file before your tests which does this automatically. See the
+[setup](./setup) section for guidance on how to set up your framework.
 
 ---
 

docs/ecosystem-jest-native.md

@@ -12,15 +12,18 @@ npm install --save-dev jest-native
 ```
 
 ```javascript
-<View>
-  <View testID="not-empty">
-    <Text testID="empty" />
-  </View>
-  <Text testID="visible">Visible Example</Text>
-</View>;
+const { getByText, getByTestId } = render(
+  <View>
+    <View testID="not-empty">
+      <Text testID="empty" />
+    </View>
+    <Text testID="visible">Text Example</Text>
+  </View>,
+);
 
-expect(queryByTestId(baseElement, 'not-empty')).not.toBeEmpty();
-expect(getByText(baseElement, 'Visible Example')).toBeVisible();
+expect(getByTestId('not-empty')).not.toBeEmpty();
+expect(getByTestId('empty')).toBeEmpty();
+expect(getByText('Visible Example')).toHaveTextContent('Text Example');
 ```
 
 > Note: when using some of these matchers, you may need to make sure you use a query function (like

docs/setup.md

@@ -15,6 +15,26 @@ preset should also work, but you'll be getting the best experience when using ou
 be some additional mocks you need to provide to such as mocks for `react-native-gesture-handler`
 when using `react-navigation`.
 
+## Cleanup
+
+You can ensure [`cleanup`](./api-main#cleanup) is called after each test and import additional
+assertions by adding it to the setup configuration in Jest.
+
+In Jest 24 and up, add the
+[`setupFilesAfterEnv`](https://jestjs.io/docs/en/configuration.html#setupfilesafterenv-array) option
+to your Jest config:
+
+```javascript
+// jest.config.js
+module.exports = {
+  setupFilesAfterEnv: [
+    'native-testing-library/cleanup-after-each',
+    // ... other setup files ...
+  ],
+  // ... other options ...
+};
+```
+
 ## Custom Render
 
 It's often useful to define a custom render method that includes things like global context

website/versioned_docs/version-3.0.0/api-main.md

@@ -169,8 +169,13 @@ test('renders into document', () => {
 // ... more tests ...
 ```
 
+In native-testing-library there is no DOM to cleanup, and your tests' rendered trees cannot
+interfere with each other. It is simply nice to be able to run any unmount logic in the components
+you have rendered in your tests.
+
 **If you don't want to add this to _every single test file_** then we recommend that you configure
-your test framework to run a file before your tests which does this automatically.
+your test framework to run a file before your tests which does this automatically. See the
+[setup](./setup) section for guidance on how to set up your framework.
 
 ---
 

website/versioned_docs/version-3.0.0/ecosystem-jest-native.md

@@ -0,0 +1,37 @@
+---
+id: version-3.0.0-ecosystem-jest-native
+title: Jest Matchers
+sidebar_label: Jest Matchers
+original_id: ecosystem-jest-native
+---
+
+[`jest-native`](https://github.com/testing-library/jest-native) is a companion library for
+`native-testing-library` that provides custom element matchers for Jest.
+
+```
+npm install --save-dev jest-native
+```
+
+```javascript
+const { getByText, getByTestId } = render(
+  <View>
+    <View testID="not-empty">
+      <Text testID="empty" />
+    </View>
+    <Text testID="visible">Text Example</Text>
+  </View>,
+);
+
+expect(getByTestId('not-empty')).not.toBeEmpty();
+expect(getByTestId('empty')).toBeEmpty();
+expect(getByText('Visible Example')).toHaveTextContent('Text Example');
+```
+
+> Note: when using some of these matchers, you may need to make sure you use a query function (like
+> `queryByTestId`) rather than a get function (like `getByTestId`). Otherwise the `get*` function
+> could throw an error before your assertion.
+
+Check out [jest-native's documentation](https://github.com/testing-library/jest-native) for a full
+list of available matchers.
+
+- [jest-native on GitHub](https://github.com/testing-library/jest-native)

website/versioned_docs/version-3.0.0/setup.md

@@ -16,6 +16,26 @@ preset should also work, but you'll be getting the best experience when using ou
 be some additional mocks you need to provide to such as mocks for `react-native-gesture-handler`
 when using `react-navigation`.
 
+## Cleanup
+
+You can ensure [`cleanup`](./api-main#cleanup) is called after each test and import additional
+assertions by adding it to the setup configuration in Jest.
+
+In Jest 24 and up, add the
+[`setupFilesAfterEnv`](https://jestjs.io/docs/en/configuration.html#setupfilesafterenv-array) option
+to your Jest config:
+
+```javascript
+// jest.config.js
+module.exports = {
+  setupFilesAfterEnv: [
+    'native-testing-library/cleanup-after-each',
+    // ... other setup files ...
+  ],
+  // ... other options ...
+};
+```
+
 ## Custom Render
 
 It's often useful to define a custom render method that includes things like global context