Does this skill cover both Playwright and Cypress?

Yes. The skill addresses end-to-end testing patterns applicable to both Playwright and Cypress, including best practices, debugging strategies, and test philosophy.

What should I NOT test with E2E according to this skill?

Unit-level logic, API contracts, edge cases, and internal implementation details—those belong in unit and integration tests. E2E should focus on critical user journeys.

How does this skill help with flaky tests?

It provides debugging techniques including headed mode, debug mode, trace viewers, and guidance on using proper waits instead of fixed timeouts to eliminate flakiness.

Does this skill include working code examples?

Yes. It includes TypeScript examples showing bad vs. good selector patterns, debugging approaches with test.step, screenshots, and pause points for inspection.

e2e-testing-patterns by wshobson

e2e-testing-patterns — detailed patterns and worked examples

Playwright Patterns

Setup and Configuration

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

export default defineConfig({
  testDir: "./e2e",
  timeout: 30000,
  expect: {
    timeout: 5000,
  },
  fullyParallel: true,
  forbidOnly: !!process.env.CI,
  retries: process.env.CI ? 2 : 0,
  workers: process.env.CI ? 1 : undefined,
  reporter: [["html"], ["junit", { outputFile: "results.xml" }]],
  use: {
    baseURL: "http://localhost:3000",
    trace: "on-first-retry",
    screenshot: "only-on-failure",
    video: "retain-on-failure",
  },
  projects: [
    { name: "chromium", use: { ...devices["Desktop Chrome"] } },
    { name: "firefox", use: { ...devices["Desktop Firefox"] } },
    { name: "webkit", use: { ...devices["Desktop Safari"] } },
    { name: "mobile", use: { ...devices["iPhone 13"] } },
  ],
});

Pattern 1: Page Object Model

// pages/LoginPage.ts
import { Page, Locator } from "@playwright/test";

export class LoginPage {
  readonly page: Page;
  readonly emailInput: Locator;
  readonly passwordInput: Locator;
  readonly loginButton: Locator;
  readonly errorMessage: Locator;

  constructor(page: Page) {
    this.page = page;
    this.emailInput = page.getByLabel("Email");
    this.passwordInput = page.getByLabel("Password");
    this.loginButton = page.getByRole("button", { name: "Login" });
    this.errorMessage = page.getByRole("alert");
  }

  async goto() {
    await this.page.goto("/login");
  }

  async login(email: string, password: string) {
    await this.emailInput.fill(email);
    await this.passwordInput.fill(password);
    await this.loginButton.click();
  }

  async getErrorMessage(): Promise<string> {
    return (await this.errorMessage.textContent()) ?? "";
  }
}

// Test using Page Object
import { test, expect } from "@playwright/test";
import { LoginPage } from "./pages/LoginPage";

test("successful login", async ({ page }) => {
  const loginPage = new LoginPage(page);
  await loginPage.goto();
  await loginPage.login("user@example.com", "password123");

  await expect(page).toHaveURL("/dashboard");
  await expect(page.getByRole("heading", { name: "Dashboard" })).toBeVisible();
});

test("failed login shows error", async ({ page }) => {
  const loginPage = new LoginPage(page);
  await loginPage.goto();
  await loginPage.login("invalid@example.com", "wrong");

  const error = await loginPage.getErrorMessage();
  expect(error).toContain("Invalid credentials");
});

Pattern 2: Fixtures for Test Data

// fixtures/test-data.ts
import { test as base } from "@playwright/test";

type TestData = {
  testUser: {
    email: string;
    password: string;
    name: string;
  };
  adminUser: {
    email: string;
    password: string;
  };
};

export const test = base.extend<TestData>({
  testUser: async ({}, use) => {
    const user = {
      email: `test-${Date.now()}@example.com`,
      password: "Test123!@#",
      name: "Test User",
    };
    // Setup: Create user in database
    await createTestUser(user);
    await use(user);
    // Teardown: Clean up user
    await deleteTestUser(user.email);
  },

  adminUser: async ({}, use) => {
    await use({
      email: "admin@example.com",
      password: process.env.ADMIN_PASSWORD!,
    });
  },
});

// Usage in tests
import { test } from "./fixtures/test-data";

test("user can update profile", async ({ page, testUser }) => {
  await page.goto("/login");
  await page.getByLabel("Email").fill(testUser.email);
  await page.getByLabel("Password").fill(testUser.password);
  await page.getByRole("button", { name: "Login" }).click();

  await page.goto("/profile");
  await page.getByLabel("Name").fill("Updated Name");
  await page.getByRole("button", { name: "Save" }).click();

  await expect(page.getByText("Profile updated")).toBeVisible();
});

Pattern 3: Waiting Strategies

// ❌ Bad: Fixed timeouts
await page.waitForTimeout(3000); // Flaky!

// ✅ Good: Wait for specific conditions
await page.waitForLoadState("networkidle");
await page.waitForURL("/dashboard");
await page.waitForSelector('[data-testid="user-profile"]');

// ✅ Better: Auto-waiting with assertions
await expect(page.getByText("Welcome")).toBeVisible();
await expect(page.getByRole("button", { name: "Submit" })).toBeEnabled();

// Wait for API response
const responsePromise = page.waitForResponse(
  (response) =>
    response.url().includes("/api/users") && response.status() === 200,
);
await page.getByRole("button", { name: "Load Users" }).click();
const response = await responsePromise;
const data = await response.json();
expect(data.users).toHaveLength(10);

// Wait for multiple conditions
await Promise.all([
  page.waitForURL("/success"),
  page.waitForLoadState("networkidle"),
  expect(page.getByText("Payment successful")).toBeVisible(),
]);

Pattern 4: Network Mocking and Interception

// Mock API responses
test("displays error when API fails", async ({ page }) => {
  await page.route("**/api/users", (route) => {
    route.fulfill({
      status: 500,
      contentType: "application/json",
      body: JSON.stringify({ error: "Internal Server Error" }),
    });
  });

  await page.goto("/users");
  await expect(page.getByText("Failed to load users")).toBeVisible();
});

// Intercept and modify requests
test("can modify API request", async ({ page }) => {
  await page.route("**/api/users", async (route) => {
    const request = route.request();
    const postData = JSON.parse(request.postData() || "{}");

    // Modify request
    postData.role = "admin";

    await route.continue({
      postData: JSON.stringify(postData),
    });
  });

  // Test continues...
});

// Mock third-party services
test("payment flow with mocked Stripe", async ({ page }) => {
  await page.route("**/api/stripe/**", (route) => {
    route.fulfill({
      status: 200,
      body: JSON.stringify({
        id: "mock_payment_id",
        status: "succeeded",
      }),
    });
  });

  // Test payment flow with mocked response
});

Cypress Patterns

Setup and Configuration

// cypress.config.ts
import { defineConfig } from "cypress";

export default defineConfig({
  e2e: {
    baseUrl: "http://localhost:3000",
    viewportWidth: 1280,
    viewportHeight: 720,
    video: false,
    screenshotOnRunFailure: true,
    defaultCommandTimeout: 10000,
    requestTimeout: 10000,
    setupNodeEvents(on, config) {
      // Implement node event listeners
    },
  },
});

Pattern 1: Custom Commands

// cypress/support/commands.ts
declare global {
  namespace Cypress {
    interface Chainable {
      login(email: string, password: string): Chainable<void>;
      createUser(userData: UserData): Chainable<User>;
      dataCy(value: string): Chainable<JQuery<HTMLElement>>;
    }
  }
}

Cypress.Commands.add("login", (email: string, password: string) => {
  cy.visit("/login");
  cy.get('[data-testid="email"]').type(email);
  cy.get('[data-testid="password"]').type(password);
  cy.get('[data-testid="login-button"]').click();
  cy.url().should("include", "/dashboard");
});

Cypress.Commands.add("createUser", (userData: UserData) => {
  return cy.request("POST", "/api/users", userData).its("body");
});

Cypress.Commands.add("dataCy", (value: string) => {
  return cy.get(`[data-cy="${value}"]`);
});

// Usage
cy.login("user@example.com", "password");
cy.dataCy("submit-button").click();

Pattern 2: Cypress Intercept

// Mock API calls
cy.intercept("GET", "/api/users", {
  statusCode: 200,
  body: [
    { id: 1, name: "John" },
    { id: 2, name: "Jane" },
  ],
}).as("getUsers");

cy.visit("/users");
cy.wait("@getUsers");
cy.get('[data-testid="user-list"]').children().should("have.length", 2);

// Modify responses
cy.intercept("GET", "/api/users", (req) => {
  req.reply((res) => {
    // Modify response
    res.body.users = res.body.users.slice(0, 5);
    res.send();
  });
});

// Simulate slow network
cy.intercept("GET", "/api/data", (req) => {
  req.reply((res) => {
    res.delay(3000); // 3 second delay
    res.send();
  });
});

Advanced Patterns

Pattern 1: Visual Regression Testing

// With Playwright
import { test, expect } from "@playwright/test";

test("homepage looks correct", async ({ page }) => {
  await page.goto("/");
  await expect(page).toHaveScreenshot("homepage.png", {
    fullPage: true,
    maxDiffPixels: 100,
  });
});

test("button in all states", async ({ page }) => {
  await page.goto("/components");

  const button = page.getByRole("button", { name: "Submit" });

  // Default state
  await expect(button).toHaveScreenshot("button-default.png");

  // Hover state
  await button.hover();
  await expect(button).toHaveScreenshot("button-hover.png");

  // Disabled state
  await button.evaluate((el) => el.setAttribute("disabled", "true"));
  await expect(button).toHaveScreenshot("button-disabled.png");
});

Pattern 2: Parallel Testing with Sharding

// playwright.config.ts
export default defineConfig({
  projects: [
    {
      name: "shard-1",
      use: { ...devices["Desktop Chrome"] },
      grepInvert: /@slow/,
      shard: { current: 1, total: 4 },
    },
    {
      name: "shard-2",
      use: { ...devices["Desktop Chrome"] },
      shard: { current: 2, total: 4 },
    },
    // ... more shards
  ],
});

// Run in CI
// npx playwright test --shard=1/4
// npx playwright test --shard=2/4

Pattern 3: Accessibility Testing

// Install: npm install @axe-core/playwright
import { test, expect } from "@playwright/test";
import AxeBuilder from "@axe-core/playwright";

test("page should not have accessibility violations", async ({ page }) => {
  await page.goto("/");

  const accessibilityScanResults = await new AxeBuilder({ page })
    .exclude("#third-party-widget")
    .analyze();

  expect(accessibilityScanResults.violations).toEqual([]);
});

test("form is accessible", async ({ page }) => {
  await page.goto("/signup");

  const results = await new AxeBuilder({ page }).include("form").analyze();

  expect(results.violations).toEqual([]);
});

/e2e-testing-patterns

referencesdetails.md

e2e-testing-patterns — detailed patterns and worked examples

Playwright Patterns

Setup and Configuration

Pattern 1: Page Object Model

Pattern 2: Fixtures for Test Data

Pattern 3: Waiting Strategies

Pattern 4: Network Mocking and Interception

Cypress Patterns

Setup and Configuration

Pattern 1: Custom Commands

Pattern 2: Cypress Intercept

Advanced Patterns

Pattern 1: Visual Regression Testing

Pattern 2: Parallel Testing with Sharding

Pattern 3: Accessibility Testing

Third-party checks

Provenance

Topics

What it does

Frequently asked

/e2e-testing-patterns

e2e-testing-patternsreferencesdetails.md

e2e-testing-patterns — detailed patterns and worked examples

Playwright Patterns

Setup and Configuration

Pattern 1: Page Object Model

Pattern 2: Fixtures for Test Data

Pattern 3: Waiting Strategies

Pattern 4: Network Mocking and Interception

Cypress Patterns

Setup and Configuration

Pattern 1: Custom Commands

Pattern 2: Cypress Intercept

Advanced Patterns

Pattern 1: Visual Regression Testing

Pattern 2: Parallel Testing with Sharding

Pattern 3: Accessibility Testing

Third-party checks

Provenance

Topics

README badge

What it does

Frequently asked

Related skills

referencesdetails.md