Add unit tests for registerStoriesWithNative

packages/rn-storybook-auto-screenshots/src/StoryRenderer.tsx

@@ -29,7 +29,8 @@ type StoryRendererProps = {
  * This allows the Android test to discover stories automatically.
  */
 let storiesRegistered = false;
-function registerStoriesWithNative() {
+/** @internal Exported for testing only */
+export function registerStoriesWithNative() {
   if (storiesRegistered || !StorybookRegistry) {
     return;
   }

packages/rn-storybook-auto-screenshots/src/__tests__/registerStoriesWithNative.test.ts

@@ -0,0 +1,100 @@
+const mockRegisterStories = jest.fn();
+
+jest.mock('react-native', () => ({
+  View: 'View',
+  Text: 'Text',
+  StyleSheet: { create: (s: any) => s },
+  NativeModules: { StorybookRegistry: { registerStories: mockRegisterStories } },
+}));
+
+jest.mock('react', () => ({
+  useEffect: jest.fn(),
+  useState: jest.fn(() => [null, jest.fn()]),
+  default: { createElement: jest.fn() },
+}));
+
+function loadFreshModule() {
+  let mod: any;
+  jest.isolateModules(() => {
+    mod = require('../StoryRenderer');
+  });
+  return mod as typeof import('../StoryRenderer');
+}
+
+describe('registerStoriesWithNative', () => {
+  beforeEach(() => {
+    mockRegisterStories.mockClear();
+  });
+
+  it('calls StorybookRegistry.registerStories with story data', () => {
+    const { configure, registerStoriesWithNative } = loadFreshModule();
+    configure({
+      _storyIndex: {
+        entries: {
+          'button--primary': { title: 'Button', name: 'Primary' },
+        },
+      },
+    });
+
+    registerStoriesWithNative();
+
+    expect(mockRegisterStories).toHaveBeenCalledWith([
+      { id: 'button--primary', title: 'Button', name: 'Primary' },
+    ]);
+  });
+
+  it('does not call registerStories when no stories are available', () => {
+    const { configure, registerStoriesWithNative } = loadFreshModule();
+    configure({ _storyIndex: { entries: {} } });
+
+    registerStoriesWithNative();
+
+    expect(mockRegisterStories).not.toHaveBeenCalled();
+  });
+
+  it('does not call registerStories when storybookView is not configured', () => {
+    const { registerStoriesWithNative } = loadFreshModule();
+
+    registerStoriesWithNative();
+
+    expect(mockRegisterStories).not.toHaveBeenCalled();
+  });
+
+  it('only registers once even if called multiple times', () => {
+    const { configure, registerStoriesWithNative } = loadFreshModule();
+    configure({
+      _storyIndex: {
+        entries: {
+          'button--primary': { title: 'Button', name: 'Primary' },
+        },
+      },
+    });
+
+    registerStoriesWithNative();
+    registerStoriesWithNative();
+    registerStoriesWithNative();
+
+    expect(mockRegisterStories).toHaveBeenCalledTimes(1);
+  });
+
+  it('logs a warning and does not throw when registerStories throws', () => {
+    const { configure, registerStoriesWithNative } = loadFreshModule();
+    configure({
+      _storyIndex: {
+        entries: {
+          'button--primary': { title: 'Button', name: 'Primary' },
+        },
+      },
+    });
+    mockRegisterStories.mockImplementation(() => {
+      throw new Error('native module error');
+    });
+
+    const warnSpy = jest.spyOn(console, 'warn').mockImplementation(() => {});
+
+    expect(() => registerStoriesWithNative()).not.toThrow();
+    expect(warnSpy).toHaveBeenCalled();
+
+    warnSpy.mockRestore();
+  });
+});