amir-rezaei
b96351ea81
[skip ci] * docs: fix trailing period, organization expansion, and comma in CONTRIBUTING.md * docs: fix withoud typo in CONTRIBUTING-NIX.md * docs: fix contraction and missing article in TESTING.md --------- Co-authored-by: ferkans-amir <amir.rezaei@tu-berlin.de> Co-authored-by: Rajarshee Chatterjee <rajarshee.adm@gmail.com>
81 lines
2.0 KiB
Markdown
81 lines
2.0 KiB
Markdown
# Testing Guide for LNReader
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This guide explains how to write tests in this React Native project using Jest and React Testing Library.
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## Existing Mocks
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### Global Mocks
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The project has global mocks configured in Jest. These are automatically applied:
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- `test/mocks/` - Global mocks for native modules (react-native-mmkv, react-navigation, all database queries, etc.)
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- `src/hooks/__mocks__/index.ts` - Hook-specific mocks (showToast, getString, parseChapterNumber, etc.)
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- `src/hooks/__tests__/mocks.ts` - Extended mocks for persisted hooks
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### Using @test-utils
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There is a custom render wrapper at `test/test-utils.tsx` with:
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- `render` - wraps with GestureHandlerRootView, SafeAreaProvider, PaperProvider, etc.
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- `renderNovel` - includes NovelContextProvider
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- `AllTheProviders` - the full provider wrapper
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Usage:
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```typescript
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import { render, renderNovel } from '@test-utils';
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```
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## Common Issues
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### 1. ESM Modules Not Transforming
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If you see `Cannot use import statement outside a module`, you need to add mocks for the module:
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```typescript
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jest.mock('@hooks/persisted/usePlugins');
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// Add more specific mocks as needed
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```
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### 2. Mock Functions Not Working
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If `mockReturnValue` throws "not a function", create mock functions at the module level:
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```typescript
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// CORRECT: Module-level mock functions
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const mockUseTheme = jest.fn();
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jest.mock('@hooks/persisted', () => ({
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useTheme: () => mockUseTheme(),
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}));
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// INCORRECT: Trying to use jest.Mock type casting
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// (useTheme as jest.Mock).mockReturnValue(...) // This fails!
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```
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### 3. Test Isolation
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Tests must mock at module level, not in `beforeEach`:
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```typescript
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// CORRECT
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const mockFn = jest.fn();
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jest.mock('module', () => ({ useHook: () => mockFn() }));
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// INCORRECT - mocks get reset between tests
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jest.mock('module');
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beforeEach(() => {
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// This doesn't work properly
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});
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```
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## Running Tests
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```bash
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pnpm test # Run all tests
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pnpm test:watch # Watch mode
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pnpm test:coverage # With coverage
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pnpm test:rn # React Native only
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pnpm test:db # Database only
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```
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