fix: jest setup was voiding custom turbo mocks (#636)

* fix: jest setup was voiding custom turbo mocks
* fix: properly scope test-specific mocks
* docs: document jest mocking on a dedicated page

__tests__/banner.test.tsx

@@ -1,9 +1,23 @@
+import * as ReactNative from 'react-native';
 import React from 'react';
 import { render } from '@testing-library/react-native';
 import { BannerAd, BannerAdSize } from '../src';
 
 const MOCK_ID = 'MOCK_ID';
 
+jest.doMock('react-native', () => {
+  return Object.setPrototypeOf(
+    {
+      ...ReactNative,
+      Platform: {
+        OS: 'android',
+        select: () => {},
+      },
+    },
+    ReactNative,
+  );
+});
+
 describe('Google Mobile Ads Banner', function () {
   it('throws if no unit ID was provided.', function () {
     let errorMsg;

docs.json

@@ -18,7 +18,8 @@
         ["European User Consent", "/european-user-consent"],
         ["Ad Inspector", "/ad-inspector"],
         ["Impression-level ad revenue", "/impression-level-ad-revenue"],
-        ["Video ad volume control", "/video-ad_volume-control"]
+        ["Video ad volume control", "/video-ad_volume-control"],
+        ["Testing", "/testing"]
       ]
     ],
     [

docs/testing.mdx

@@ -0,0 +1,17 @@
+# Testing
+
+The React Native Google Mobile Ads library depends on a lot of platform-specific native code which you likely want to mock in your tests.
+
+## Testing with Jest
+
+This library ships with a Jest setup file that mocks the native code for you.
+To use it, add the following to your Jest configuration:
+
+```json
+// jest.config.js|ts|mjs|cjs|json
+{
+  "setupFiles": [
+    "./node_modules/react-native-google-mobile-ads/jest.setup.ts"
+  ]
+}
+```

jest.setup.ts

@@ -3,10 +3,6 @@ import * as ReactNative from 'react-native';
 jest.doMock('react-native', () => {
   return Object.setPrototypeOf(
     {
-      Platform: {
-        OS: 'android',
-        select: () => {},
-      },
       NativeModules: {
         ...ReactNative.NativeModules,
         RNAppModule: {
@@ -28,6 +24,7 @@ jest.doMock('react-native', () => {
         RNGoogleMobileAdsConsentModule: {},
       },
       TurboModuleRegistry: {
+        ...ReactNative.TurboModuleRegistry,
         getEnforcing: () => {
           return {
             initialize: jest.fn(),