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

bash

bun add -D vitest @vitest/coverage-v8

typescript

// 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

typescript

// 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: 'test@example.com',
      password: 'token',
    }),
  },
}));

Unit Test Examples

typescript

// 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

typescript

// 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

bash

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

typescript

// 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

bash

bun add -D @vue/test-utils

typescript

// 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

bash

bun add -D @playwright/test
bunx playwright install

typescript

// 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,
  },
});

typescript

// 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"]', 'test@example.com');
    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"]', 'wrong@example.com');
    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

bash

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

typescript

// 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',
};

typescript

// 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

bash

bun add -D detox

javascript

// .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

swift

// 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

kotlin

// 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

kotlin

// 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

typescript

// 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

yaml

# .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

capacitor-testing

NPX Install

Tags

SKILL.md Content

Testing Capacitor Applications

When to Use This Skill

Testing Pyramid

Unit Testing

Setup with Vitest

Mock Capacitor Plugins

Unit Test Examples

Testing Utilities

Component Testing

React Testing Library

Vue Test Utils

E2E Testing

Playwright for Web

Appium for Native

Detox for React Native Style Testing

Native Testing

iOS XCTest

Android JUnit

Android Instrumented Tests

Testing Best Practices

Test Organization

Mock Best Practices

CI Configuration

Resources