Mobile App Testing

Implement comprehensive testing strategies for mobile applications.

Testing Pyramid

Level Tools Coverage

Unit Jest, XCTest, JUnit 70%

Integration Detox, Espresso 20%

E2E Appium, Detox 10%

React Native (Jest + Detox)

// Unit test describe('CartService', () => { it('calculates total correctly', () => { const cart = new CartService(); cart.addItem({ price: 10, quantity: 2 }); expect(cart.getTotal()).toBe(20); }); });

// E2E test (Detox) describe('Login flow', () => { beforeEach(async () => { await device.reloadReactNative(); });

it('should login successfully', async () => { await element(by.id('email-input')).typeText('user@example.com'); await element(by.id('password-input')).typeText('password123'); await element(by.id('login-button')).tap(); await expect(element(by.id('dashboard'))).toBeVisible(); }); });

iOS (XCTest)

func testLoginSuccess() { let app = XCUIApplication() app.launch()

app.textFields["email"].tap()
app.textFields["email"].typeText("user@example.com")
app.secureTextFields["password"].typeText("password123")
app.buttons["Login"].tap()

XCTAssertTrue(app.staticTexts["Welcome"].exists)

}

Android (Espresso)

@Test fun loginSuccess() { onView(withId(R.id.email)).perform(typeText("user@example.com")) onView(withId(R.id.password)).perform(typeText("password123")) onView(withId(R.id.loginButton)).perform(click()) onView(withId(R.id.dashboard)).check(matches(isDisplayed())) }

Best Practices

• Test business logic first (unit tests)

• Mock external dependencies

• Test both success and failure paths

• Automate critical user flows

• Maintain >80% code coverage

• Test on real devices periodically

Avoid

• Testing implementation details

• Hardcoded test data

• Interdependent tests

• Skipping error case testing