playwright-bdd-step-definitions（Playwright BDD step definitions 搜索）

Playwright BDD Step Definitions

Expert knowledge of creating step definitions for Playwright BDD, including step functions, parameter types, fixtures, and Page Object Model integration.

Overview

Step definitions connect Gherkin steps in feature files to executable code. Playwright BDD uses createBdd() to generate type-safe step definition functions that integrate with Playwright's fixtures and assertions.

Basic Step Definitions

Creating Step Functions

// steps/common.steps.ts
import { createBdd } from 'playwright-bdd';

const { Given, When, Then } = createBdd();

Given('I am on the home page', async ({ page }) => {
  await page.goto('/');
});

When('I click the login button', async ({ page }) => {
  await page.getByRole('button', { name: 'Login' }).click();
});

Then('I should see the dashboard', async ({ page }) => {
  await expect(page.getByRole('heading', { name: 'Dashboard' })).toBeVisible();
});

Step with Playwright Fixtures

All Playwright fixtures are available in step definitions:

import { createBdd } from 'playwright-bdd';

const { Given, When, Then } = createBdd();

Given('I am logged in as {string}', async ({ page, context }, username: string) => {
  // Access page and context fixtures
  await page.goto('/login');
  await page.getByLabel('Username').fill(username);
  await page.getByRole('button', { name: 'Login' }).click();
});

When('I take a screenshot', async ({ page }) => {
  await page.screenshot({ path: 'screenshot.png' });
});

Then('the browser has {int} cookies', async ({ context }, count: number) => {
  const cookies = await context.cookies();
  expect(cookies).toHaveLength(count);
});

Parameter Types

Built-in Parameters

// String parameter: {string}
Given('the user name is {string}', async ({}, name: string) => {
  console.log(name); // "John"
});

// Integer parameter: {int}
When('I wait {int} seconds', async ({}, seconds: number) => {
  await page.waitForTimeout(seconds * 1000);
});

// Float parameter: {float}
Then('the price is {float}', async ({}, price: number) => {
  console.log(price); // 19.99
});

// Word parameter: {word}
Given('I am on the {word} page', async ({ page }, pageName: string) => {
  await page.goto(`/${pageName}`);
});

Anonymous Parameters

Use regex capture groups for flexible matching:

// Match any text in quotes
Given(/^I enter "(.*)" in the search box$/, async ({ page }, query: string) => {
  await page.getByRole('searchbox').fill(query);
});

// Match numbers
When(/^I add (\d+) items to cart$/, async ({ page }, count: string) => {
  const quantity = parseInt(count, 10);
  for (let i = 0; i < quantity; i++) {
    await page.getByRole('button', { name: 'Add to Cart' }).click();
  }
});

Custom Parameter Types

Define reusable parameter types:

// steps/parameters.ts
import { defineParameterType } from 'playwright-bdd';

defineParameterType({
  name: 'color',
  regexp: /red|green|blue/,
  transformer: (s) => s,
});

defineParameterType({
  name: 'boolean',
  regexp: /true|false/,
  transformer: (s) => s === 'true',
});

defineParameterType({
  name: 'date',
  regexp: /\d{4}-\d{2}-\d{2}/,
  transformer: (s) => new Date(s),
});

Using custom parameters:

// steps/ui.steps.ts
import { createBdd } from 'playwright-bdd';
import './parameters'; // Import parameter definitions

const { Given, When, Then } = createBdd();

When('I select the {color} theme', async ({ page }, color: string) => {
  await page.getByRole('button', { name: color }).click();
});

Then('dark mode is {boolean}', async ({ page }, enabled: boolean) => {
  if (enabled) {
    await expect(page.locator('body')).toHaveClass(/dark/);
  }
});

Custom Fixtures

Creating Custom Fixtures

// steps/fixtures.ts
import { test as base, createBdd } from 'playwright-bdd';

// Define fixture types
type TestFixtures = {
  todoPage: TodoPage;
  apiClient: ApiClient;
};

// Extend base test with fixtures
export const test = base.extend<TestFixtures>({
  todoPage: async ({ page }, use) => {
    const todoPage = new TodoPage(page);
    await use(todoPage);
  },

  apiClient: async ({ request }, use) => {
    const client = new ApiClient(request);
    await use(client);
  },
});

// Create BDD functions with custom test
export const { Given, When, Then } = createBdd(test);

Using Custom Fixtures in Steps

// steps/todo.steps.ts
import { Given, When, Then } from './fixtures';

Given('I have an empty todo list', async ({ todoPage }) => {
  await todoPage.goto();
  await todoPage.clearAll();
});

When('I add a todo {string}', async ({ todoPage }, text: string) => {
  await todoPage.addTodo(text);
});

Then('I should see {int} todos', async ({ todoPage }, count: number) => {
  await todoPage.expectTodoCount(count);
});

Fixture with Setup and Teardown

// steps/fixtures.ts
import { test as base, createBdd } from 'playwright-bdd';

export const test = base.extend<{
  authenticatedPage: Page;
}>({
  authenticatedPage: async ({ page, context }, use) => {
    // Setup: Login before test
    await page.goto('/login');
    await page.getByLabel('Email').fill('test@example.com');
    await page.getByLabel('Password').fill('password');
    await page.getByRole('button', { name: 'Login' }).click();
    await page.waitForURL('/dashboard');

    // Use the authenticated page
    await use(page);

    // Teardown: Logout after test
    await page.goto('/logout');
  },
});

export const { Given, When, Then } = createBdd(test);

Page Object Model

Page Object Definition

// pages/TodoPage.ts
import { Page, Locator, expect } from '@playwright/test';

export class TodoPage {
  readonly page: Page;
  readonly input: Locator;
  readonly list: Locator;
  readonly items: Locator;

  constructor(page: Page) {
    this.page = page;
    this.input = page.getByPlaceholder('What needs to be done?');
    this.list = page.getByRole('list');
    this.items = page.getByTestId('todo-item');
  }

  async goto() {
    await this.page.goto('/todos');
  }

  async addTodo(text: string) {
    await this.input.fill(text);
    await this.input.press('Enter');
  }

  async removeTodo(text: string) {
    const item = this.items.filter({ hasText: text });
    await item.hover();
    await item.getByRole('button', { name: 'Delete' }).click();
  }

  async toggleTodo(text: string) {
    const item = this.items.filter({ hasText: text });
    await item.getByRole('checkbox').click();
  }

  async expectTodoCount(count: number) {
    await expect(this.items).toHaveCount(count);
  }

  async expectTodoVisible(text: string) {
    await expect(this.items.filter({ hasText: text })).toBeVisible();
  }

  async clearAll() {
    const count = await this.items.count();
    for (let i = count - 1; i >= 0; i--) {
      await this.items.nth(i).hover();
      await this.items.nth(i).getByRole('button', { name: 'Delete' }).click();
    }
  }
}

Integrating Page Objects with Steps

// steps/fixtures.ts
import { test as base, createBdd } from 'playwright-bdd';
import { TodoPage } from '../pages/TodoPage';
import { LoginPage } from '../pages/LoginPage';

export const test = base.extend<{
  todoPage: TodoPage;
  loginPage: LoginPage;
}>({
  todoPage: async ({ page }, use) => {
    await use(new TodoPage(page));
  },
  loginPage: async ({ page }, use) => {
    await use(new LoginPage(page));
  },
});

export const { Given, When, Then } = createBdd(test);

// steps/todo.steps.ts
import { Given, When, Then } from './fixtures';

Given('I am on the todo page', async ({ todoPage }) => {
  await todoPage.goto();
});

When('I add {string} to my todos', async ({ todoPage }, text: string) => {
  await todoPage.addTodo(text);
});

When('I complete the todo {string}', async ({ todoPage }, text: string) => {
  await todoPage.toggleTodo(text);
});

When('I remove the todo {string}', async ({ todoPage }, text: string) => {
  await todoPage.removeTodo(text);
});

Then('I should see the todo {string}', async ({ todoPage }, text: string) => {
  await todoPage.expectTodoVisible(text);
});

Then('there should be {int} todos', async ({ todoPage }, count: number) => {
  await todoPage.expectTodoCount(count);
});

Decorator-Based Steps

Using Decorators with Classes

// steps/TodoSteps.ts
import { Fixture, Given, When, Then } from 'playwright-bdd/decorators';
import { test } from './fixtures';

export
@Fixture<typeof test>('todoPage')
class TodoSteps {
  @Given('I am on the todo page')
  async gotoTodoPage() {
    await this.todoPage.goto();
  }

  @When('I add {string} to my todos')
  async addTodo(text: string) {
    await this.todoPage.addTodo(text);
  }

  @Then('I should see {int} todos')
  async checkTodoCount(count: number) {
    await this.todoPage.expectTodoCount(count);
  }
}

Multiple Fixtures in Decorators

// steps/AuthenticatedSteps.ts
import { Fixture, Given, When, Then } from 'playwright-bdd/decorators';
import { test } from './fixtures';

export
@Fixture<typeof test>('loginPage')
@Fixture<typeof test>('todoPage')
class AuthenticatedSteps {
  @Given('I am logged in')
  async login() {
    await this.loginPage.login('user@example.com', 'password');
  }

  @When('I visit my todos')
  async visitTodos() {
    await this.todoPage.goto();
  }
}

Data Tables

Simple Tables

When I add the following todos:
  | Buy milk  |
  | Buy bread |
  | Buy eggs  |

import { DataTable } from '@cucumber/cucumber';

When('I add the following todos:', async ({ todoPage }, table: DataTable) => {
  const todos = table.raw().flat();
  for (const todo of todos) {
    await todoPage.addTodo(todo);
  }
});

Tables with Headers

When I create users:
  | name  | email           | role  |
  | Alice | alice@test.com  | admin |
  | Bob   | bob@test.com    | user  |

When('I create users:', async ({ page }, table: DataTable) => {
  const users = table.hashes(); // [{ name: 'Alice', email: '...', role: 'admin' }, ...]
  for (const user of users) {
    await page.getByLabel('Name').fill(user.name);
    await page.getByLabel('Email').fill(user.email);
    await page.getByLabel('Role').selectOption(user.role);
    await page.getByRole('button', { name: 'Create' }).click();
  }
});

Vertical Tables

When I fill the form:
  | Name     | John Doe        |
  | Email    | john@example.com|
  | Password | secret123       |

When('I fill the form:', async ({ page }, table: DataTable) => {
  const data = table.rowsHash(); // { Name: 'John Doe', Email: '...', Password: '...' }
  await page.getByLabel('Name').fill(data.Name);
  await page.getByLabel('Email').fill(data.Email);
  await page.getByLabel('Password').fill(data.Password);
});

Doc Strings

Multi-line Text Input

When I write the following review:
  """
  This product is amazing!
  I highly recommend it to everyone.
  Five stars!
  """

When('I write the following review:', async ({ page }, docString: string) => {
  await page.getByRole('textbox', { name: 'Review' }).fill(docString);
});

JSON Data

When I send the API request:
  """json
  {
    "name": "Test Product",
    "price": 29.99,
    "category": "electronics"
  }
  """

When('I send the API request:', async ({ request }, docString: string) => {
  const data = JSON.parse(docString);
  await request.post('/api/products', { data });
});

Sharing State Between Steps

Using World/Context

// steps/fixtures.ts
import { test as base, createBdd } from 'playwright-bdd';

type World = {
  currentUser?: { id: string; name: string };
  createdItems: string[];
};

export const test = base.extend<{ world: World }>({
  world: async ({}, use) => {
    await use({
      createdItems: [],
    });
  },
});

export const { Given, When, Then } = createBdd(test);

// steps/user.steps.ts
import { Given, When, Then } from './fixtures';

Given('I am logged in as {string}', async ({ page, world }, name: string) => {
  world.currentUser = { id: '123', name };
  await page.goto('/login');
  // ... login steps
});

When('I create an item {string}', async ({ world }, item: string) => {
  world.createdItems.push(item);
  // ... create item
});

Then('I should see my items', async ({ page, world }) => {
  for (const item of world.createdItems) {
    await expect(page.getByText(item)).toBeVisible();
  }
});

Error Handling

Pending Steps

Given('a feature not yet implemented', async ({}) => {
  throw new Error('Step not implemented');
});

Skip Steps Conditionally

Given('I am on a supported browser', async ({ browserName }) => {
  if (browserName === 'webkit') {
    test.skip(true, 'Feature not supported on WebKit');
  }
  // Continue with test
});

Best Practices

Step Reusability

Write generic steps that work across multiple scenarios:

// Generic navigation step
Given('I am on the {string} page', async ({ page }, pageName: string) => {
  const routes: Record<string, string> = {
    home: '/',
    login: '/login',
    dashboard: '/dashboard',
    settings: '/settings',
  };
  await page.goto(routes[pageName] || `/${pageName}`);
});

// Generic form fill step
When('I fill in {string} with {string}', async ({ page }, label: string, value: string) => {
  await page.getByLabel(label).fill(value);
});

// Generic click step
When('I click {string}', async ({ page }, text: string) => {
  await page.getByRole('button', { name: text }).or(
    page.getByRole('link', { name: text })
  ).click();
});

Step Organization

Organize steps by domain:

steps/
├── fixtures.ts          # Shared fixtures
├── parameters.ts        # Custom parameter types
├── common/
│   ├── navigation.steps.ts
│   └── forms.steps.ts
├── auth/
│   ├── login.steps.ts
│   └── logout.steps.ts
└── products/
    ├── catalog.steps.ts
    └── cart.steps.ts

Assertions

Use Playwright's expect for assertions:

import { expect } from '@playwright/test';

Then('I should see {string}', async ({ page }, text: string) => {
  await expect(page.getByText(text)).toBeVisible();
});

Then('the page title should be {string}', async ({ page }, title: string) => {
  await expect(page).toHaveTitle(title);
});

Then('the URL should contain {string}', async ({ page }, path: string) => {
  await expect(page).toHaveURL(new RegExp(path));
});

When to Use This Skill

• Creating new step definitions
• Implementing Page Object Model with BDD
• Setting up custom fixtures
• Using data tables and doc strings
• Sharing state between steps
• Writing reusable generic steps
• Converting Cucumber steps to Playwright BDD
• Troubleshooting step matching issues