88 lines
3.5 KiB
Markdown
88 lines
3.5 KiB
Markdown
# Puppeteer unit tests
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Unit tests in Puppeteer are written using [Mocha] as the test runner and [Expect] as the assertions library.
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## Test state
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We have some common setup that runs before each test and is defined in `mocha-utils.js`.
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You can use the `getTestState` function to read state. It exposes the following that you can use in your tests. These will be reset/tidied between tests automatically for you:
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- `puppeteer`: an instance of the Puppeteer library. This is exactly what you'd get if you ran `require('puppeteer')`.
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- `puppeteerPath`: the path to the root source file for Puppeteer.
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- `defaultBrowserOptions`: the default options the Puppeteer browser is launched from in test mode, so tests can use them and override if required.
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- `server`: a dummy test server instance (see `utils/testserver` for more).
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- `httpsServer`: a dummy test server HTTPS instance (see `utils/testserver` for more).
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- `isFirefox`: true if running in Firefox.
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- `isChrome`: true if running Chromium.
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- `isHeadless`: true if the test is in headless mode.
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If your test needs a browser instance, you can use the `setupTestBrowserHooks()` function which will automatically configure a browser that will be cleaned between each test suite run. You access this via `getTestState()`.
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If your test needs a Puppeteer page and context, you can use the `setupTestPageAndContextHooks()` function which will configure these. You can access `page` and `context` from `getTestState()` once you have done this.
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The best place to look is an existing test to see how they use the helpers.
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## Skipping tests in specific conditions
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Tests that are not expected to pass in Firefox can be skipped. You can skip an individual test by using `itFailsFirefox` rather than `it`. Similarly you can skip a describe block with `describeFailsFirefox`.
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There is also `describeChromeOnly` and `itChromeOnly` which will only execute the test if running in Chromium. Note that this is different from `describeFailsFirefox`: the goal is to get any `FailsFirefox` calls passing in Firefox, whereas `describeChromeOnly` should be used to test behaviour that will only ever apply in Chromium.
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There are also tests that assume a normal install flow, with browser binaries ending up in `.local-<browser>`, for example. Such tests are skipped with
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`itOnlyRegularInstall` which checks `BINARY` and `PUPPETEER_ALT_INSTALL` environment variables.
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[mocha]: https://mochajs.org/
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[expect]: https://www.npmjs.com/package/expect
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## Running tests
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Despite being named 'unit', these are integration tests, making sure public API methods and events work as expected.
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- To run all tests:
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```bash
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npm run test:unit
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```
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- **Important**: don't forget to first run TypeScript if you're testing local changes:
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```bash
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npm run build:tsc && npm run test:unit
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```
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- To run a specific test, substitute the `it` with `it.only`:
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```js
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...
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it.only('should work', async function() {
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const {server, page} = getTestState();
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const response = await page.goto(server.EMPTY_PAGE);
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expect(response.ok).toBe(true);
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});
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```
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- To disable a specific test, substitute the `it` with `xit` (mnemonic rule: '_cross it_'):
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```js
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...
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// Using "xit" to skip specific test
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xit('should work', async function({server, page}) {
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const {server, page} = getTestState();
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const response = await page.goto(server.EMPTY_PAGE);
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expect(response.ok).toBe(true);
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});
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```
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- To run tests in non-headless mode:
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```bash
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HEADLESS=false npm run test:unit
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```
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- To run tests with custom browser executable:
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```bash
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BINARY=<path-to-executable> npm run test:unit
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```
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