name: capacitor-testing
description: Complete testing guide for Capacitor apps covering unit tests, integration tests, E2E tests, and native testing. Includes Jest, Vitest, Playwright, Appium, and native testing frameworks. Use this skill when users need to test their mobile apps.

Testing Capacitor Applications

Comprehensive testing strategies for Capacitor mobile apps.

When to Use This Skill

• User wants to add tests
• User asks about testing strategies
• User needs E2E testing
• User wants to mock native plugins
• User needs CI testing setup

Testing Pyramid

        /\
       /  \        E2E Tests (Few)
      /----\       - Real devices
     /      \      - Full user flows
    /--------\     Integration Tests (Some)
   /          \    - Component interactions
  /------------\   - API integration
 /              \  Unit Tests (Many)
/----------------\ - Pure functions
                   - Business logic

Unit Testing

Setup with Vitest

bun add -D vitest @vitest/coverage-v8

// vitest.config.ts
import { defineConfig } from 'vitest/config';

export default defineConfig({
  test: {
    globals: true,
    environment: 'jsdom',
    coverage: {
      provider: 'v8',
      reporter: ['text', 'json', 'html'],
    },
    setupFiles: ['./src/test/setup.ts'],
  },
});

Mock Capacitor Plugins

// src/test/setup.ts
import { vi } from 'vitest';

// Mock @capacitor/core
vi.mock('@capacitor/core', () => ({
  Capacitor: {
    isNativePlatform: vi.fn(() => true),
    getPlatform: vi.fn(() => 'ios'),
    isPluginAvailable: vi.fn(() => true),
  },
  registerPlugin: vi.fn(),
}));

// Mock @capacitor/preferences
vi.mock('@capacitor/preferences', () => ({
  Preferences: {
    get: vi.fn(),
    set: vi.fn(),
    remove: vi.fn(),
    clear: vi.fn(),
  },
}));

// Mock @capgo/capacitor-native-biometric
vi.mock('@capgo/capacitor-native-biometric', () => ({
  NativeBiometric: {
    isAvailable: vi.fn().mockResolvedValue({
      isAvailable: true,
      biometryType: 'touchId',
    }),
    verifyIdentity: vi.fn().mockResolvedValue({}),
    setCredentials: vi.fn().mockResolvedValue({}),
    getCredentials: vi.fn().mockResolvedValue({
      username: '[email protected]',
      password: 'token',
    }),
  },
}));

Unit Test Examples

// src/services/auth.test.ts
import { describe, it, expect, vi, beforeEach } from 'vitest';
import { AuthService } from './auth';
import { NativeBiometric } from '@capgo/capacitor-native-biometric';

describe('AuthService', () => {
  beforeEach(() => {
    vi.clearAllMocks();
  });

  describe('biometricLogin', () => {
    it('should authenticate with biometrics', async () => {
      const authService = new AuthService();

      const result = await authService.biometricLogin();

      expect(NativeBiometric.verifyIdentity).toHaveBeenCalledWith({
        reason: 'Authenticate to login',
        title: 'Biometric Login',
      });
      expect(result).toBe(true);
    });

    it('should return false when biometrics unavailable', async () => {
      vi.mocked(NativeBiometric.isAvailable).mockResolvedValueOnce({
        isAvailable: false,
        biometryType: 'none',
      });

      const authService = new AuthService();
      const result = await authService.biometricLogin();

      expect(result).toBe(false);
    });

    it('should handle user cancellation', async () => {
      vi.mocked(NativeBiometric.verifyIdentity).mockRejectedValueOnce(
        new Error('User cancelled')
      );

      const authService = new AuthService();
      const result = await authService.biometricLogin();

      expect(result).toBe(false);
    });
  });
});

Testing Utilities

// src/test/utils.ts
import { Capacitor } from '@capacitor/core';
import { vi } from 'vitest';

export function mockPlatform(platform: 'ios' | 'android' | 'web') {
  vi.mocked(Capacitor.getPlatform).mockReturnValue(platform);
  vi.mocked(Capacitor.isNativePlatform).mockReturnValue(platform !== 'web');
}

export function mockPluginAvailable(available: boolean) {
  vi.mocked(Capacitor.isPluginAvailable).mockReturnValue(available);
}

// Usage in tests
describe('Platform-specific behavior', () => {
  it('should use iOS-specific code on iOS', () => {
    mockPlatform('ios');
    // Test iOS behavior
  });

  it('should use Android-specific code on Android', () => {
    mockPlatform('android');
    // Test Android behavior
  });
});

Component Testing

React Testing Library

bun add -D @testing-library/react @testing-library/user-event

// src/components/LoginButton.test.tsx
import { render, screen, waitFor } from '@testing-library/react';
import userEvent from '@testing-library/user-event';
import { LoginButton } from './LoginButton';
import { NativeBiometric } from '@capgo/capacitor-native-biometric';

describe('LoginButton', () => {
  it('should show biometric option when available', async () => {
    render(<LoginButton />);

    await waitFor(() => {
      expect(screen.getByText('Login with Face ID')).toBeInTheDocument();
    });
  });

  it('should call biometric auth on click', async () => {
    const user = userEvent.setup();
    render(<LoginButton />);

    const button = await screen.findByRole('button', { name: /face id/i });
    await user.click(button);

    expect(NativeBiometric.verifyIdentity).toHaveBeenCalled();
  });
});

Vue Test Utils

bun add -D @vue/test-utils

// src/components/LoginButton.spec.ts
import { mount, flushPromises } from '@vue/test-utils';
import LoginButton from './LoginButton.vue';
import { NativeBiometric } from '@capgo/capacitor-native-biometric';

describe('LoginButton', () => {
  it('should render biometric button', async () => {
    const wrapper = mount(LoginButton);
    await flushPromises();

    expect(wrapper.text()).toContain('Login with Biometrics');
  });

  it('should trigger authentication on click', async () => {
    const wrapper = mount(LoginButton);
    await flushPromises();

    await wrapper.find('button').trigger('click');

    expect(NativeBiometric.verifyIdentity).toHaveBeenCalled();
  });
});

E2E Testing

Playwright for Web

bun add -D @playwright/test
bunx playwright install

// playwright.config.ts
import { defineConfig, devices } from '@playwright/test';

export default defineConfig({
  testDir: './e2e',
  fullyParallel: true,
  use: {
    baseURL: 'http://localhost:5173',
    trace: 'on-first-retry',
  },
  projects: [
    {
      name: 'chromium',
      use: { ...devices['Desktop Chrome'] },
    },
    {
      name: 'Mobile Safari',
      use: { ...devices['iPhone 14'] },
    },
    {
      name: 'Mobile Chrome',
      use: { ...devices['Pixel 7'] },
    },
  ],
  webServer: {
    command: 'bun run dev',
    url: 'http://localhost:5173',
    reuseExistingServer: !process.env.CI,
  },
});

// e2e/login.spec.ts
import { test, expect } from '@playwright/test';

test.describe('Login Flow', () => {
  test('should login with email and password', async ({ page }) => {
    await page.goto('/login');

    await page.fill('[data-testid="email"]', '[email protected]');
    await page.fill('[data-testid="password"]', 'password123');
    await page.click('[data-testid="login-button"]');

    await expect(page).toHaveURL('/dashboard');
    await expect(page.locator('h1')).toContainText('Welcome');
  });

  test('should show error for invalid credentials', async ({ page }) => {
    await page.goto('/login');

    await page.fill('[data-testid="email"]', '[email protected]');
    await page.fill('[data-testid="password"]', 'wrong');
    await page.click('[data-testid="login-button"]');

    await expect(page.locator('[data-testid="error"]')).toBeVisible();
  });
});

Appium for Native

bun add -D webdriverio @wdio/appium-service @wdio/mocha-framework

// wdio.conf.ts
export const config: WebdriverIO.Config = {
  runner: 'local',
  specs: ['./e2e/native/**/*.spec.ts'],
  capabilities: [
    {
      platformName: 'iOS',
      'appium:deviceName': 'iPhone 15',
      'appium:platformVersion': '17.0',
      'appium:app': './ios/App/build/App.app',
      'appium:automationName': 'XCUITest',
    },
    {
      platformName: 'Android',
      'appium:deviceName': 'Pixel 8',
      'appium:platformVersion': '14',
      'appium:app': './android/app/build/outputs/apk/debug/app-debug.apk',
      'appium:automationName': 'UiAutomator2',
    },
  ],
  services: ['appium'],
  framework: 'mocha',
};

// e2e/native/login.spec.ts
describe('Native Login', () => {
  it('should login with biometrics', async () => {
    // Wait for app to load
    await $('~login-screen').waitForExist();

    // Tap biometric button
    await $('~biometric-login').click();

    // Simulate biometric auth (device-specific)
    if (driver.isIOS) {
      await driver.touchId(true);
    } else {
      await driver.fingerPrint(1);
    }

    // Verify logged in
    await expect($('~dashboard')).toBeExisting();
  });
});

Detox for React Native Style Testing

bun add -D detox

// .detoxrc.js
module.exports = {
  testRunner: {
    $0: 'jest',
    args: {
      config: 'e2e/jest.config.js',
    },
  },
  apps: {
    'ios.debug': {
      type: 'ios.app',
      binaryPath: 'ios/App/build/App.app',
      build: 'cd ios && xcodebuild ...',
    },
    'android.debug': {
      type: 'android.apk',
      binaryPath: 'android/app/build/outputs/apk/debug/app-debug.apk',
      build: 'cd android && ./gradlew assembleDebug',
    },
  },
  devices: {
    simulator: {
      type: 'ios.simulator',
      device: { type: 'iPhone 15' },
    },
    emulator: {
      type: 'android.emulator',
      device: { avdName: 'Pixel_8_API_34' },
    },
  },
};

Native Testing

iOS XCTest

// ios/AppTests/PluginTests.swift
import XCTest
@testable import App
import Capacitor

class PluginTests: XCTestCase {
    var bridge: MockBridge!

    override func setUp() {
        super.setUp()
        bridge = MockBridge()
    }

    func testPluginMethodReturnsExpectedValue() {
        let plugin = MyPlugin(bridge: bridge, pluginId: "MyPlugin", pluginName: "MyPlugin")

        let call = CAPPluginCall(callbackId: "test", options: ["value": "test"], success: { result, call in
            XCTAssertEqual(result?.data?["value"] as? String, "test")
        }, error: { error in
            XCTFail("Should not error")
        })

        plugin.echo(call!)
    }
}

Android JUnit

// android/app/src/test/java/com/example/PluginTest.kt
import org.junit.Test
import org.junit.Assert.*
import org.mockito.Mockito.*

class PluginTest {
    @Test
    fun `echo returns input value`() {
        val plugin = MyPlugin()
        val call = mock(PluginCall::class.java)

        `when`(call.getString("value")).thenReturn("test")

        plugin.echo(call)

        verify(call).resolve(argThat { data ->
            data.getString("value") == "test"
        })
    }
}

Android Instrumented Tests

// android/app/src/androidTest/java/com/example/PluginInstrumentedTest.kt
import androidx.test.ext.junit.runners.AndroidJUnit4
import androidx.test.platform.app.InstrumentationRegistry
import org.junit.Test
import org.junit.runner.RunWith
import org.junit.Assert.*

@RunWith(AndroidJUnit4::class)
class PluginInstrumentedTest {
    @Test
    fun useAppContext() {
        val appContext = InstrumentationRegistry.getInstrumentation().targetContext
        assertEquals("com.example.app", appContext.packageName)
    }
}

Testing Best Practices

Test Organization

src/
├── components/
│   ├── Button.tsx
│   └── Button.test.tsx      # Unit tests next to component
├── services/
│   ├── auth.ts
│   └── auth.test.ts
├── test/
│   ├── setup.ts             # Test setup
│   ├── mocks/               # Shared mocks
│   └── utils.ts             # Test utilities
e2e/
├── web/                     # Playwright tests
│   └── login.spec.ts
└── native/                  # Appium tests
    └── login.spec.ts

Mock Best Practices

// Don't over-mock - test real behavior when possible
// BAD
vi.mock('./api', () => ({
  fetchUser: vi.fn().mockResolvedValue({ id: 1, name: 'Test' }),
}));

// GOOD - Use MSW for API mocking
import { setupServer } from 'msw/node';
import { rest } from 'msw';

const server = setupServer(
  rest.get('/api/user', (req, res, ctx) => {
    return res(ctx.json({ id: 1, name: 'Test' }));
  })
);

beforeAll(() => server.listen());
afterEach(() => server.resetHandlers());
afterAll(() => server.close());

CI Configuration

# .github/workflows/test.yml
name: Tests

on: [push, pull_request]

jobs:
  unit:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: oven-sh/setup-bun@v1
      - run: bun install
      - run: bun test --coverage

  e2e:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: oven-sh/setup-bun@v1
      - run: bun install
      - run: bunx playwright install --with-deps
      - run: bun run build
      - run: bunx playwright test

  ios:
    runs-on: macos-latest
    steps:
      - uses: actions/checkout@v4
      - run: cd ios/App && xcodebuild test -scheme App -destination 'platform=iOS Simulator,name=iPhone 15'

  android:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-java@v4
        with:
          java-version: '17'
          distribution: 'temurin'
      - run: cd android && ./gradlew test

Resources

• Vitest Documentation: https://vitest.dev
• Playwright Documentation: https://playwright.dev
• Testing Library: https://testing-library.com
• Appium Documentation: https://appium.io