--- id: test-snapshots title: "Visual comparisons" --- Playwright Test includes the ability to produce and visually compare screenshots using `expect(value).toMatchSnapshot()`. On first execution, Playwright test will generate reference screenshots. Subsequent runs will compare against the reference. ```js js-flavor=js // example.spec.js const { test, expect } = require('@playwright/test'); test('example test', async ({ page }) => { await page.goto('https://playwright.dev'); expect(await page.screenshot()).toMatchSnapshot('optional-snapshot-name.png'); }); ``` ```js js-flavor=ts // example.spec.ts import { test, expect } from '@playwright/test'; test('example test', async ({ page }) => { await page.goto('https://playwright.dev'); expect(await page.screenshot()).toMatchSnapshot('optional-snapshot-name.png'); }); ``` Sometimes you need to update the reference screenshot, for example when the page has changed. Do this with the `--update-snapshots` flag. ```bash npx playwright test --update-snapshots ``` Playwright Test uses the [pixelmatch](https://github.com/mapbox/pixelmatch) library. You can pass comparison `threshold` as an option. ```js js-flavor=js // example.spec.js const { test, expect } = require('@playwright/test'); test('example test', async ({ page }) => { await page.goto('https://playwright.dev'); expect(await page.screenshot()).toMatchSnapshot({ threshold: 0.2 }); }); ``` ```js js-flavor=ts // example.spec.ts import { test, expect } from '@playwright/test'; test('example test', async ({ page }) => { await page.goto('https://playwright.dev'); expect(await page.screenshot()).toMatchSnapshot({ threshold: 0.2 }); }); ``` Apart from screenshots, `expect(value).toMatchSnapshot()` can also be used to compare text, png and jpeg images, or arbitrary binary data. Playwright Test auto-detects the content type and uses the appropriate comparison algorithm. Here we compare text content against the reference. ```js js-flavor=js // example.spec.js const { test, expect } = require('@playwright/test'); test('example test', async ({ page }) => { await page.goto('https://playwright.dev'); expect(await page.textContent('.hero__title')).toMatchSnapshot(); }); ``` ```js js-flavor=ts // example.spec.ts import { test, expect } from '@playwright/test'; test('example test', async ({ page }) => { await page.goto('https://playwright.dev'); expect(await page.textContent('.hero__title')).toMatchSnapshot(); }); ``` Snapshots are stored next to the test file, in a separate directory. For example, `my.spec.js` file will produce and store snapshots in the `my.spec.js-snapshots` directory. You should commit this directory to your version control (e.g. `git`), and review any changes to it.