playwright skill

---
name: playwright
description: >
  Playwright E2E testing patterns.
  Trigger: When writing E2E tests - Page Objects, selectors, MCP workflow.
license: Apache-2.0
metadata:
  author: gentleman-programming
  version: "1.1"
---

## MCP Workflow (MANDATORY If Available)

**⚠️ If you have Playwright MCP tools, ALWAYS use them BEFORE creating any test:**

1. **Navigate** to target page
2. **Take snapshot** to see page structure and elements
3. **Interact** with forms/elements to verify exact user flow
4. **Take screenshots** to document expected states
5. **Verify page transitions** through complete flow (loading, success, error)
6. **Document actual selectors** from snapshots (use real refs and labels)
7. **Only after exploring** create test code with verified selectors

**If MCP NOT available:** Proceed with test creation based on docs and code analysis.

**Why This Matters:**
- ✅ Precise tests - exact steps needed, no assumptions
- ✅ Accurate selectors - real DOM structure, not imagined
- ✅ Real flow validation - verify journey actually works
- ✅ Avoid over-engineering - minimal tests for what exists
- ✅ Prevent flaky tests - real exploration = stable tests
- ❌ Never assume how UI "should" work

## File Structure

```
tests/
├── base-page.ts              # Parent class for ALL pages
├── helpers.ts                # Shared utilities
└── {page-name}/
    ├── {page-name}-page.ts   # Page Object Model
    ├── {page-name}.spec.ts   # ALL tests here (NO separate files!)
    └── {page-name}.md        # Test documentation
```

**File Naming:**
- ✅ `sign-up.spec.ts` (all sign-up tests)
- ✅ `sign-up-page.ts` (page object)
- ✅ `sign-up.md` (documentation)
- ❌ `sign-up-critical-path.spec.ts` (WRONG - no separate files)
- ❌ `sign-up-validation.spec.ts` (WRONG)

## Selector Priority (REQUIRED)

```typescript
// 1. BEST - getByRole for interactive elements
this.submitButton = page.getByRole("button", { name: "Submit" });
this.navLink = page.getByRole("link", { name: "Dashboard" });

// 2. BEST - getByLabel for form controls
this.emailInput = page.getByLabel("Email");
this.passwordInput = page.getByLabel("Password");

// 3. SPARINGLY - getByText for static content only
this.errorMessage = page.getByText("Invalid credentials");
this.pageTitle = page.getByText("Welcome");

// 4. LAST RESORT - getByTestId when above fail
this.customWidget = page.getByTestId("date-picker");

// ❌ AVOID fragile selectors
this.button = page.locator(".btn-primary");  // NO
this.input = page.locator("#email");         // NO
```

## Scope Detection (ASK IF AMBIGUOUS)

| User Says | Action |
|-----------|--------|
| "a test", "one test", "new test", "add test" | Create ONE test() in existing spec |
| "comprehensive tests", "all tests", "test suite", "generate tests" | Create full suite |

**Examples:**
- "Create a test for user sign-up" → ONE test only
- "Generate E2E tests for login page" → Full suite
- "Add a test to verify form validation" → ONE test to existing spec

## Page Object Pattern

```typescript
import { Page, Locator, expect } from "@playwright/test";

// BasePage - ALL pages extend this
export class BasePage {
  constructor(protected page: Page) {}

  async goto(path: string): Promise<void> {
    await this.page.goto(path);
    await this.page.waitForLoadState("networkidle");
  }

  // Common methods go here (see Refactoring Guidelines)
  async waitForNotification(): Promise<void> {
    await this.page.waitForSelector('[role="status"]');
  }

  async verifyNotificationMessage(message: string): Promise<void> {
    const notification = this.page.locator('[role="status"]');
    await expect(notification).toContainText(message);
  }
}

// Page-specific implementation
export interface LoginData {
  email: string;
  password: string;
}

export class LoginPage extends BasePage {
  readonly emailInput: Locator;
  readonly passwordInput: Locator;
  readonly submitButton: Locator;

  constructor(page: Page) {
    super(page);
    this.emailInput = page.getByLabel("Email");
    this.passwordInput = page.getByLabel("Password");
    this.submitButton = page.getByRole("button", { name: "Sign in" });
  }

  async goto(): Promise<void> {
    await super.goto("/login");
  }

  async login(data: LoginData): Promise<void> {
    await this.emailInput.fill(data.email);
    await this.passwordInput.fill(data.password);
    await this.submitButton.click();
  }

  async verifyCriticalOutcome(): Promise<void> {
    await expect(this.page).toHaveURL("/dashboard");
  }
}
```

## Page Object Reuse (CRITICAL)

**Always check existing page objects before creating new ones!**

```typescript
// ✅ GOOD: Reuse existing page objects
import { SignInPage } from "../sign-in/sign-in-page";
import { HomePage } from "../home/home-page";

test("User can sign up and login", async ({ page }) => {
  const signUpPage = new SignUpPage(page);
  const signInPage = new SignInPage(page);  // REUSE
  const homePage = new HomePage(page);      // REUSE

  await signUpPage.signUp(userData);
  await homePage.verifyPageLoaded();  // REUSE method
  await homePage.signOut();           // REUSE method
  await signInPage.login(credentials); // REUSE method
});

// ❌ BAD: Recreating existing functionality
export class SignUpPage extends BasePage {
  async logout() { /* ... */ }  // ❌ HomePage already has this
  async login() { /* ... */ }   // ❌ SignInPage already has this
}
```

**Guidelines:**
- Check `tests/` for existing page objects first
- Import and reuse existing pages
- Create page objects only when page doesn't exist
- If test requires multiple pages, ensure all page objects exist (create if needed)

## Refactoring Guidelines

### Move to `BasePage` when:
- ✅ Navigation helpers used by multiple pages (`waitForPageLoad()`, `getCurrentUrl()`)
- ✅ Common UI interactions (notifications, modals, theme toggles)
- ✅ Verification patterns repeated across pages (`isVisible()`, `waitForVisible()`)
- ✅ Error handling that applies to all pages
- ✅ Screenshot utilities for debugging

### Move to `helpers.ts` when:
- ✅ Test data generation (`generateUniqueEmail()`, `generateTestUser()`)
- ✅ Setup/teardown utilities (`createTestUser()`, `cleanupTestData()`)
- ✅ Custom assertions (`expectNotificationToContain()`)
- ✅ API helpers for test setup (`seedDatabase()`, `resetState()`)
- ✅ Time utilities (`waitForCondition()`, `retryAction()`)

**Before (BAD):**
```typescript
// Repeated in multiple page objects
export class SignUpPage extends BasePage {
  async waitForNotification(): Promise<void> {
    await this.page.waitForSelector('[role="status"]');
  }
}
export class SignInPage extends BasePage {
  async waitForNotification(): Promise<void> {
    await this.page.waitForSelector('[role="status"]');  // DUPLICATED!
  }
}
```

**After (GOOD):**
```typescript
// BasePage - shared across all pages
export class BasePage {
  async waitForNotification(): Promise<void> {
    await this.page.waitForSelector('[role="status"]');
  }
}

// helpers.ts - data generation
export function generateUniqueEmail(): string {
  return `test.${Date.now()}@example.com`;
}

export function generateTestUser() {
  return {
    name: "Test User",
    email: generateUniqueEmail(),
    password: "TestPassword123!",
  };
}
```

## Test Pattern with Tags

```typescript
import { test, expect } from "@playwright/test";
import { LoginPage } from "./login-page";

test.describe("Login", () => {
  test("User can login successfully",
    { tag: ["@critical", "@e2e", "@login", "@LOGIN-E2E-001"] },
    async ({ page }) => {
      const loginPage = new LoginPage(page);

      await loginPage.goto();
      await loginPage.login({ email: "[email protected]", password: "pass123" });

      await expect(page).toHaveURL("/dashboard");
    }
  );
});
```

**Tag Categories:**
- Priority: `@critical`, `@high`, `@medium`, `@low`
- Type: `@e2e`
- Feature: `@signup`, `@signin`, `@dashboard`
- Test ID: `@SIGNUP-E2E-001`, `@LOGIN-E2E-002`

## Test Documentation Format ({page-name}.md)

```markdown
### E2E Tests: {Feature Name}

**Suite ID:** `{SUITE-ID}`
**Feature:** {Feature description}

---

## Test Case: `{TEST-ID}` - {Test case title}

**Priority:** `{critical|high|medium|low}`

**Tags:**
- type → @e2e
- feature → @{feature-name}

**Description/Objective:** {Brief description}

**Preconditions:**
- {Prerequisites for test to run}
- {Required data or state}

### Flow Steps:
1. {Step 1}
2. {Step 2}
3. {Step 3}

### Expected Result:
- {Expected outcome 1}
- {Expected outcome 2}

### Key verification points:
- {Assertion 1}
- {Assertion 2}

### Notes:
- {Additional considerations}
```

**Documentation Rules:**
- ❌ NO general test running instructions
- ❌ NO file structure explanations
- ❌ NO code examples or tutorials
- ❌ NO troubleshooting sections
- ✅ Focus ONLY on specific test case
- ✅ Keep under 60 lines when possible

## Commands

```bash
npx playwright test                    # Run all
npx playwright test --grep "login"     # Filter by name
npx playwright test --ui               # Interactive UI
npx playwright test --debug            # Debug mode
npx playwright test tests/login/       # Run specific folder
```

## Keywords
playwright, e2e, testing, page object model, selectors, end-to-end, mcp