playwright-bdd-rk v1.0.4

playwright-bdd-rk

Run BDD tests with Playwright test runner.

This is a fork of https://github.com/vitalets/playwright-bdd with support for auto including tags on the end of title lines. Tags are appended to the generated files (as typically you don't see or work with them).
This package appends the tags on the feature, scenario, outline and outline example titles and makes it easy to select tests by appending -g "tag(s)" to the npx playwright test command. This enhancement also avoids the need to override the Scenario Outline Example row titles to ensure they have unique names.

This project is experimental and under development and will hopefully be folded back into its parent project (maybe with its functionality being a commnd line option).

With version 1.0.2 and above bddgen can be passed a logical expression of tags, for example

npx bddgen "@login and (@scenario1 or @scenario2)" && npx playwright test

and, or, not and parenthesis can be included in the tag expression.

This provides a much more conventional means of specifying the tests to run than Playwright's grep command line parameter (which can still be used).

The generated files are pruned to only include the features, scenarios and outline examples that match the bddgen tag expression.

If no tag expression is provided then bddgen should behave as the parent project, ie tags will not be added to feature/scenario titles/names (v1.0.4 and above).

Inspired by the issue in Playwright repo microsoft/playwright#11975

Contents

• Why Playwright runner
• Installation
• Get started
• Configuration
  • ESM
• Writing features
  • Run single feature
  • Skip feature
  • Customize examples title
• Writing steps
  • Playwright-style
    • Custom fixtures
    • Accessing testInfo
    • Using tags
    • Using DataTables
  • Cucumber-style
    • World
    • Custom World
• Watch mode
• Debugging
• API
• VS Code Integration
• How it works
• FAQ
  • Is it possible to run BDD tests in a single command?
  • Is it possible to apply test.use() in a generated test file?
• Limitations
• Changelog
• Feedback
• License

Why Playwright runner

Both Playwright and CucumberJS have their own test runners. You can use CucumberJS runner with Playwright as a library to test BDD scenarios. This package offers alternative way: convert BDD scenarios into Playwright tests and run them with Playwright runner as usual. Such approach brings all the benefits of Playwright runner:

• Automatic browser initialization and cleanup
• Usage of Playwright fixtures
• Parallelize execution with sharding
• ...a lot more

Installation

Install from npm:

npm i -D playwright-bdd-rk

This package uses @playwright/test and @cucumber/cucumber as a peer dependencies, so you may need to install them as well:

npm i -D @playwright/test @cucumber/cucumber

After installing Playwright you may need to install browsers:

npx playwright install

Get started

You can follow steps below to setup playwright-bdd-rk manually or clone playwright-bdd-rk-example to quickly check how it works.

1. Create the following Playwright config in the project root:

   // playwright.config.js
   import { defineConfig } from '@playwright/test';
   import { defineBddConfig } from 'playwright-bdd-rk';
   
   const testDir = defineBddConfig({
     paths: ['sample.feature'],
     require: ['steps.js'],
   });
   
   export default defineConfig({
     testDir,
     reporter: 'html',
   });

2. Describe feature in sample.feature:

   Feature: Playwright site
   
       Scenario: Check title
           Given I open url "https://playwright.dev"
           When I click link "Get started"
           Then I see in title "Playwright"

3. Implement steps in steps.js:

   import { expect } from '@playwright/test';
   import { createBdd } from 'playwright-bdd-rk';
   
   const { Given, When, Then } = createBdd();
   
   Given('I open url {string}', async ({ page }, url) => {
     await page.goto(url);
   });
   
   When('I click link {string}', async ({ page }, name) => {
     await page.getByRole('link', { name }).click();
   });
   
   Then('I see in title {string}', async ({ page }, keyword) => {
     await expect(page).toHaveTitle(new RegExp(keyword));
   });

   There is alternative Cucumber-compatible syntax for step definitions, see Writing steps.

4. Generate and run tests:

   npx bddgen && npx playwright test

   Output:

   Running 1 test using 1 worker
   1 passed (2.0s)
   
   To open last HTML report run:
   
   npx playwright show-report

5. (Optional) Check out .features-gen directory to see what generated tests look like ;)

Configuration

Configuration is passed to defineBddConfig() inside Playwright config file. Most options are from CucumberJS and there are a few special ones.

Typical CucumberJS options:

See more options in CucumberJS docs.

Note: Cucumber's option requireModule: ['ts-node/register'] is not recommended for playwright-bdd-rk. TypeScript compilation is performed with Playwright's built-in loader.

Special playwright-bdd-rk options: | Name | Type | Description |----------------------|------------|------------------------ | outputDir | string | Directory to output generated test files. Default: .features-gen | importTestFrom | string | Path to file that exports custom test to be used in generated files. Default: playwright-bdd-rk | examplesTitleFormat| string | Title format for scenario outline examples in generated tests. Default: Example #<_index_> | verbose | boolean | Verbose output. Default: false

Example configuration (CommonJS TypeScript project):

import { defineConfig } from '@playwright/test';
import { defineBddConfig } from 'playwright-bdd-rk';

const testDir = defineBddConfig({
  importTestFrom: 'fixtures.ts',
  paths: ['feature/*.feature'],
  require: ['steps/**/*.ts'],
});

export default defineConfig({
  testDir,
});

Return value of defineBddConfig() is a resolved output directory where test files will be generated. It is convenient to use it as a testDir option for Playwright.

If there is an external cucumber.js config file, it is also merged into configuration.

ESM

If your project runs in ESM (has "type": "module" in package.json), the configuration in playwright.config.js is following:

For JavaScript ESM:

const testDir = defineBddConfig({,
-  require: ['steps.js'],
+  import: ['steps.js'],
});

For TypeScript ESM:

const testDir = defineBddConfig({,
-  require: ['steps.js'],
+  import: ['steps.ts'],
});

Command to run tests:

NODE_OPTIONS='--loader ts-node/esm --no-warnings' npx bddgen && npx playwright test

Writing features

Write features in *.feature files using Gherkin syntax. All keywords are supported.

Example:

Feature: Playwright site

    Scenario: Check title
        Given I open url "https://playwright.dev"
        When I click link "Get started"
        Then I see in title "Playwright"

Run single feature

Use @only tag to run a single feature / scenario:

@only
Feature: Playwright site
    
    @only
    Scenario: Check title
        Given I open url "https://playwright.dev"

Skip feature

Use @skip (or @fixme) tag to skip a particular feature / scenario:

@skip
Feature: Playwright site

    @skip
    Scenario: Check title
        Given I open url "https://playwright.dev"

Customize examples title

By default each row from Scenario Outline examples is converted into test with title Example #{index}. It can be not reliable for reporters that keep track of test history, because on every insertion / deletion of rows test titles will shift.

You can provide own fixed title format by adding a special comment right above Examples. The comment should start with # title-format: and can reference column names as <column>:

Feature: calculator

    Scenario Outline: Check doubled
      Then Doubled <start> equals <end>

      # title-format: Example for <start>
      Examples:
          | start | end |
          |    2  |   4 |
          |    3  |   6 |

Generated test file:

test.describe("calculator", () => {

  test.describe("Check doubled", () => {

    test("Example for 2", async ({ Then }) => {
      await Then("Doubled 2 equals 4");
    });

    test("Example for 3", async ({ Then }) => {
      await Then("Doubled 3 equals 6");
    });

Writing steps

There are two ways of writing step definitions: 1. Playwright-style - recommended for new projects or adding BDD to existing Playwright projects 2. Cucumber-style - recommended for migrating existing CucumberJS projects to Playwright runner

Playwright-style

Playwright-style allows you to write step definitions like a regular playwright tests. You get all benefits of custom fixtures, both test-scoped and worker-scoped.

Playwright-style highlights:

• use Given, When, Then from createBdd() call (see example below)
• use arrow functions for step definitions
• don't use World and before/after hooks (use fixtures instead)

Example:

import { createBdd } from 'playwright-bdd-rk';

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

Given('I open url {string}', async ({ page }, url: string) => {
  await page.goto(url);
});

When('I click link {string}', async ({ page }, name: string) => {
  await page.getByRole('link', { name }).click();
});

Custom fixtures

To use custom fixtures in step definitions:

1. Define custom fixtures with .extend() and export test instance. For example, fixtures.ts:

   // Note: import base from playwright-bdd-rk, not from @playwright/test!
   import { test as base } from 'playwright-bdd-rk';
   
   // custom fixture
   class MyPage {
     constructor(public page: Page) {}
   
     async openLink(name: string) {
       await this.page.getByRole('link', { name }).click();
     }
   }
   
   // export custom test function
   export const test = base.extend<{ myPage: MyPage }>({
     myPage: async ({ page }, use) => {
       await use(new MyPage(page));
     }
   });

2. Pass custom test function to createBdd() and use customs fixtures in step definitions. For example, steps.ts:

   import { createBdd } from 'playwright-bdd-rk';
   import { test } from './fixtures';
   
   const { Given, When, Then } = createBdd(test);
   
   Given('I open url {string}', async ({ myPage }, url: string) => { ... });
   When('I click link {string}', async ({ myPage }, name: string) => { ... });
   Then('I see in title {string}', async ({ myPage }, text: string) => { ... });

3. Set config option importTestFrom which points to file exporting custom test function. For example:

   const testDir = defineBddConfig({
     importTestFrom: './fixtures.ts',
     // ...
   });

   Generated files, before and after:

   -import { test } from "playwright-bdd-rk";  
   +import { test } from "./fixtures.ts";  

See full example of Playwright-style.

Accessing testInfo

To access testInfo for conditionally skipping tests, attaching screenshots, etc. use special $testInfo fixture:

Given('I do something', async ({ $testInfo }) => { 
  console.log($testInfo.title); // logs test title "I do something"
  $testInfo.skip(); // skips test
});

Using tags

Cucumber tags can be accessed by special $tags fixture:

@slow
Feature: Playwright site
    
    @jira:123
    Scenario: Check title
      Given I do something
      ...

In step definition:

Given('I do something', async ({ $tags }) => {
  console.log($tags); // outputs ["@slow", "@jira:123"]
});

Special tags @only, @skip and @fixme are excluded from $tags to avoid impact on test during debug

The most powerfull usage of $tags is in your custom fixtures. For example, you can overwrite viewport for mobile version:

Feature: Playwright site
    
    @mobile
    Scenario: Check title
      Given I do something
      ...

Custom fixtures.ts:

import { test as base } from 'playwright-bdd-rk';

export const test = base.extend({
  viewport: async ({ $tags, viewport }, use) => {
    if ($tags.includes('@mobile')) {
      viewport = { width: 375, height: 667 };
    }
    await use(viewport);
  }
});

This fork appends cucumber tags to test titles when generating the intermediate files. This is done as there is no indication on when Playwright will directly support tags, see microsoft/playwright#23180.

This means that putting Playwright tags before a Feature, Scenario, Outline or Examples:

@feature
Feature: Playwright site

    @slow
    Scenario: Check title
      ...

will generate in the intermediate files (which should not be edited):

Feature: Playwright site @feature

    Scenario: Check title @feature @slow
      ...

Using DataTables

Playwright-bdd-rk provides full support of DataTables. For example:

Feature: Some feature

    Scenario: Login
        When I fill login form with values
          | label     | value    |
          | Username  | vitalets |
          | Password  | 12345    |

Step definition:

import { createBdd } from 'playwright-bdd-rk';
import { DataTable } from '@cucumber/cucumber';

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

When('I fill login form with values', async ({ page }, data: DataTable) => {
  for (const row of data.hashes()) {
    await page.getByLabel(row.label).fill(row.value);
  }
  /*
  data.hashes() returns:
  [
    { label: 'Username', value: 'vitalets' },
    { label: 'Password', value: '12345' }
  ]
  */
});

Check out all methods of DataTable in Cucumber docs.

Cucumber-style

Cucumber-style step definitions are compatible with CucumberJS:

• import Given, When, Then from @cucumber/cucumber package
• use regular functions for steps (not arrow functions!)
• use World from playwright-bdd-rk to access Playwright API

Example (TypeScript):

import { Given, When, Then } from '@cucumber/cucumber';
import { World } from 'playwright-bdd-rk';
import { expect } from '@playwright/test';

Given('I open url {string}', async function (this: World, url: string) {
  await this.page.goto(url);
});

When('I click link {string}', async function (this: World, name: string) {
  await this.page.getByRole('link', { name }).click();
});

Then('I see in title {string}', async function (this: World, keyword: string) {
  await expect(this.page).toHaveTitle(new RegExp(keyword));
});

World

Playwright-bdd-rk extends Cucumber World with Playwright built-in fixtures and testInfo. Simply use this.page or this.testInfo in step definitions:

import { Given, When, Then } from '@cucumber/cucumber';

Given('I open url {string}', async function (url) {
  await this.page.goto(url);
});

In TypeScript you should import World from playwright-bdd-rk for proper typing:

import { Given, When, Then } from '@cucumber/cucumber';
import { World } from 'playwright-bdd-rk';

Given('I open url {string}', async function (this: World, url: string) {
  await this.page.goto(url);
});

Check out all available props of World.

Custom World

To use Custom World you should inherit it from playwright-bdd-rk World and pass to Cucumber's setWorldConstructor:

import { setWorldConstructor } from '@cucumber/cucumber';
import { World, WorldOptions } from 'playwright-bdd-rk';

export class CustomWorld extends World {
  myBaseUrl: string;
  constructor(options: WorldOptions) {
    super(options);
    this.myBaseUrl = 'https://playwright.dev';
  }

  async init() {
    await this.page.goto(this.myBaseUrl);
  }
}

setWorldConstructor(CustomWorld);

Consider asynchronous setup and teardown of World instance with init() / destroy() methods.

See full example of Cucumber-style.

Watch mode

To watch feature / steps files and automatically regenerate tests you can use nodemon:

npx nodemon -w ./features -w ./steps -e feature,js,ts --exec 'npx bddgen'

To automatically rerun tests after changes you can run the above command together with Playwright --ui mode, utilizing npm-run-all. Example package.json:

"scripts": {
  "watch:bdd": "nodemon -w ./features -w ./steps -e feature,js,ts --exec 'npx bddgen'",
  "watch:pw": "playwright test --ui",
  "watch": "run-p watch:*"
}

Debugging

You can debug tests as usual with --debug flag:

npx bddgen && npx playwright test --debug

See more info on debugging in Playwright docs.

API

defineBddConfig(config)

Defines BDD config inside Playwright config file.

Params

• config object - BDD configuration

Returns: string - directory where test files will be generated

createBdd(test?)

Creates Given, When, Then functions for defining steps.

Params

• test object - custom test instance

Returns: object - { Given, When, Then }

Given(fixtures, ...args)

Defines Given step implementation.

Params

• fixtures object - Playwright fixtures
• ...args array - arguments captured from step pattern

When(fixtures, ...args)

Defines When step implementation.

Params

• fixtures object - Playwright fixtures
• ...args array - arguments captured from step pattern

Then(fixtures, ...args)

Defines Then step implementation.

Params

• fixtures object - Playwright fixtures
• ...args array - arguments captured from step pattern

VS Code Integration

• Playwright extension works the usual way. You can click and run tests from .features-gen directory:

• Cucumber autocompletion works as usual:

How it works

Phase 1: Generate Playwright test files from BDD feature files

From

Feature: Playwright site

    Scenario: Check title
        Given I open url "https://playwright.dev"
        When I click link "Get started"
        Then I see in title "Playwright"

To

import { test } from 'playwright-bdd-rk';

test.describe('Playwright site', () => {

  test('Check title', async ({ Given, When, Then }) => {
    await Given('I open url "https://playwright.dev"');
    await When('I click link "Get started"');
    await Then('I see in title "Playwright"');
  });

});    

Phase 2: Run test files with Playwright runner

Playwright runner executes generated test files as it would normally do. Playwright-bdd-rk automatically provides Playwright API (page, browser, etc) in step definitions:

Given('I open url {string}', async ({ page }, url) => {
  await page.goto(url);
});

When('I click link {string}', async ({ page }, name) => {
  await page.getByRole('link', { name }).click();
});

Then('I see in title {string}', async ({ page }, text) => {
  await expect(page).toHaveTitle(new RegExp(text));
});  

FAQ

Is it possible to run BDD tests in a single command?

This approach was initially implemented: test files were generated directly in playwright.config.ts before test execution. It allowed to run tests with npx playwright test instead of having two commands as npx bddgen && npx playwright test. But later several issues appeared:

1. It became really hard to decide when to generate test files because Playwright config is executed many times from different sources: workers, VS Code extension, UI mode, etc.

2. Implementation of watch mode is tricky. It is impossible to just run nodemon with playwright.config.ts. Separate command for test generation allows to easily support watch mode

3. Watching files in --ui mode leads to circullar dependency: a change in test files triggers test run which in turn re-imports config and once again triggers a change in test files

For now decoupling test generation from test running is a better solution for integration with Playwright's tooling.

Is it possible to apply test.use() in a generated test file?

Test files generation is a fully automatic process, no manual interceptions allowed. But instead of applying test.use (that has impact to all tests in a file) you can utilize tags with custom fixtures. That is more flexible approach and allows to selectively change settings for a particular scenario/test.

Limitations

Currently there are some limitations:

• Cucumber hooks are not supported yet, see #15. For now, consider using Playwright fixtures instead, that are more flexible and straightforward.

Changelog

Please check out CHANGELOG.md.

Feedback

Feel free to share your feedback in issues. This way you will help Playwright team to proceed with BDD implementation in Playwright core.

License

MIT