playwright/docs/src/test-retries-js.md
2021-10-14 19:28:47 -07:00

5.7 KiB
Raw Blame History

id title
test-retries Test retry

Failures

Playwright Test runs tests in worker processes. These processes are OS processes, running independently, orchestrated by the test runner. All workers have identical environments and each starts its own browser.

Consider the following snippet:

const { test } = require('@playwright/test');

test.describe('suite', () => {
  test('first good', async ({ page }) => { /* ... */ });
  test('second flaky', async ({ page }) => { /* ... */ });
  test('third good', async ({ page }) => { /* ... */ });
});
import { test } from '@playwright/test';

test.describe('suite', () => {
  test('first good', async ({ page }) => { /* ... */ });
  test('second flaky', async ({ page }) => { /* ... */ });
  test('third good', async ({ page }) => { /* ... */ });
});

When all tests pass, they will run in order in the same worker process.

  • Worker process starts
    • first good passes
    • second flaky passes
    • third good passes

Should any test fail, Playwright Test will discard the entire worker process along with the browser and will start a new one. Testing will continue in the new worker process starting with the next test.

  • Worker process #1 starts
    • first good passes
    • second flaky fails
  • Worker process #2 starts
    • third good passes

If you enable retries, second worker process will start by retrying the failed test and continue from there.

  • Worker process #1 starts
    • first good passes
    • second flaky fails
  • Worker process #2 starts
    • second flaky is retried and passes
    • third good passes

This scheme works perfectly for independent tests and guarantees that failing tests can't affect healthy ones.

Retries

Playwright Test supports test retries. When enabled, failing tests will be retried multiple times until they pass, or until the maximum number of retries is reached. By default failing tests are not retried.

# Give failing tests 3 retry attempts
npx playwright test --retries=3
// playwright.config.js
// @ts-check

/** @type {import('@playwright/test').PlaywrightTestConfig} */
const config = {
  // Give failing tests 3 retry attempts
  retries: 3,
};

module.exports = config;
// playwright.config.ts
import { PlaywrightTestConfig } from '@playwright/test';

const config: PlaywrightTestConfig = {
  // Give failing tests 3 retry attempts
  retries: 3,
};
export default config;

Playwright Test will categorize tests as follows:

  • "passed" - tests that passed on the first run;
  • "flaky" - tests that failed on the first run, but passed when retried;
  • "failed" - tests that failed on the first run and failed all retries.
Running 3 tests using 1 worker

  ✓ example.spec.ts:4:2  first passes (438ms)
  x example.spec.ts:5:2  second flaky (691ms)
  ✓ example.spec.ts:5:2  second flaky (522ms)
  ✓ example.spec.ts:6:2  third passes (932ms)

  1 flaky
    example.spec.ts:5:2  second flaky
  2 passed (4s)

Serial mode

Use [method: Test.describe.serial] to group dependent tests to ensure they will always run together and in order. If one of the tests fails, all subsequent tests are skipped. All tests in the group are retried together.

Consider the following snippet that uses test.describe.serial:

const { test } = require('@playwright/test');

test.describe.serial('suite', () => {
  test('first good', async ({ page }) => { /* ... */ });
  test('second flaky', async ({ page }) => { /* ... */ });
  test('third good', async ({ page }) => { /* ... */ });
});
import { test } from '@playwright/test';

test.describe.serial('suite', () => {
  test('first good', async ({ page }) => { /* ... */ });
  test('second flaky', async ({ page }) => { /* ... */ });
  test('third good', async ({ page }) => { /* ... */ });
});

When running without retries, all tests after the failure are skipped:

  • Worker process #1:
    • first good passes
    • second flaky fails
    • third good is skipped entirely

When running with retries, all tests are retried together:

  • Worker process #1:
    • first good passes
    • second flaky fails
    • third good is skipped
  • Worker process #2:
    • first good passes again
    • second flaky passes
    • third good passes

:::note It is usually better to make your tests isolated, so they can be efficiently run and retried independently. :::

Reuse single page between tests

Playwright Test creates an isolated [Page] object for each test. However, if you'd like to reuse a single [Page] object between multiple tests, you can create your own in [method: Test.beforeAll] and close it in [method: Test.afterAll].

// example.spec.js
// @ts-check

const { test } = require('@playwright/test');

test.describe.serial('use the same page', () => {
  /** @type {import('@playwright/test').Page} */
  let page;

  test.beforeAll(async ({ browser }) => {
    page = await browser.newPage();
  });

  test.afterAll(async () => {
    await page.close();
  });

  test('runs first', async () => {
    await page.goto('https://playwright.dev/');
  });

  test('runs second', async () => {
    await page.click('text=Get Started');
  });
});
// example.spec.ts

import { test, Page } from '@playwright/test';

test.describe.serial('use the same page', () => {
  let page: Page;

  test.beforeAll(async ({ browser }) => {
    page = await browser.newPage();
  });

  test.afterAll(async () => {
    await page.close();
  });

  test('runs first', async () => {
    await page.goto('https://playwright.dev/');
  });

  test('runs second', async () => {
    await page.click('text=Get Started');
  });
});