Test Automation

Build robust automated test suites using modern frameworks like Selenium, Cypress, and Playwright for efficient regression testing.

When to Use This Skill

• Regression testing automation
• CI/CD integration
• API testing automation
• Cross-browser testing
• Performance testing
• Smoke test automation
• Data-driven testing
• Continuous testing

Core Concepts

1. Cypress Test Example

// cypress/e2e/login.cy.js
describe('User Login', () => {
  beforeEach(() => {
    cy.visit('/login')
  })

  it('should login successfully with valid credentials', () => {
    cy.get('[data-testid="email"]').type('user@example.com')
    cy.get('[data-testid="password"]').type('SecurePass123!')
    cy.get('[data-testid="login-btn"]').click()

    cy.url().should('include', '/dashboard')
    cy.get('[data-testid="welcome-msg"]')
      .should('contain', 'Welcome')
  })

  it('should show error with invalid credentials', () => {
    cy.get('[data-testid="email"]').type('invalid@example.com')
    cy.get('[data-testid="password"]').type('wrong')
    cy.get('[data-testid="login-btn"]').click()

    cy.get('[data-testid="error-msg"]')
      .should('be.visible')
      .and('contain', 'Invalid credentials')
  })
})

2. Page Object Model

// pages/LoginPage.js
class LoginPage {
  get emailInput() { return cy.get('[data-testid="email"]') }
  get passwordInput() { return cy.get('[data-testid="password"]') }
  get loginButton() { return cy.get('[data-testid="login-btn"]') }
  get errorMessage() { return cy.get('[data-testid="error-msg"]') }

  login(email, password) {
    this.emailInput.type(email)
    this.passwordInput.type(password)
    this.loginButton.click()
  }

  verifyLoginError(message) {
    this.errorMessage.should('contain', message)
  }
}

export default new LoginPage()

// Test using Page Object
import LoginPage from '../pages/LoginPage'

it('login test', () => {
  cy.visit('/login')
  LoginPage.login('user@example.com', 'password')
})

3. API Test Example (REST Assured - Java)

@Test
public void testGetUser() {
    given()
        .baseUri("https://api.example.com")
        .header("Authorization", "Bearer " + token)
        .pathParam("id", "123")
    .when()
        .get("/users/{id}")
    .then()
        .statusCode(200)
        .body("id", equalTo("123"))
        .body("name", notNullValue())
        .body("email", containsString("@"));
}

Best Practices

1. Use selectors wisely - data-testid over CSS
2. Page Object Model - Maintainable structure
3. Wait strategies - Explicit over implicit
4. Independent tests - No test dependencies
5. Test data management - Fixtures, factories
6. Clear assertions - Meaningful error messages
7. Screenshot on failure - Debug information
8. CI/CD integration - Automated execution

Resources

• Cypress: https://www.cypress.io
• Playwright: https://playwright.dev
• Selenium: https://www.selenium.dev