79016b879f
## Summary This PR adds a new `worker` strategy to the `<Script />` component that automatically relocates and executes the script in a web worker. ```jsx <Script strategy="worker" ... /> ``` [Partytown](https://partytown.builder.io/) is used under the hood to provide this functionality. ## Behavior - This will land as an experimental feature and will only work behind an opt-in flag in `next.config.js`: ```js experimental: { nextScriptWorkers: true } ``` - This setup use a similar approach to how ESLint and Typescript is used in Next.js by showing an error to the user to install the dependency locally themselves if they've enabled the experimental `nextScriptWorkers` flag. <img width="1068" alt="Screen Shot 2022-03-03 at 2 33 13 PM" src="https://user-images.githubusercontent.com/12476932/156639227-42af5353-a2a6-4126-936e-269112809651.png"> - For Partytown to work, a number of static files must be served directly from the site (see [docs](https://partytown.builder.io/copy-library-files)). In this PR, these files are automatically copied to a `~partytown` directory in `.next/static` during `next build` and `next dev` if the `nextScriptWorkers` flag is set to true. ## Checklist - [X] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR. - [X] Related issues linked using `fixes #number` - [X] Integration tests added - [X] Documentation added - [ ] Telemetry added. In case of a feature if it's used or not. This PR fixes #31517. |
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| .stats-app | ||
| development | ||
| e2e | ||
| integration | ||
| lib | ||
| production | ||
| unit | ||
| .gitignore | ||
| jest-setup-after-env.ts | ||
| readme.md | ||
| test-file.txt | ||
Writing tests for Next.js
Getting Started
You can set-up a new test using yarn new-test which will start from a template related to the test type.
Test Types in Next.js
- e2e: These tests will run against
next devandnext start - development: These tests only run against
next dev - production: These tests will run against
next start. - integration: These tests run misc checks and modes and is where tests used to be added before we added more specific folders. Ideally we don't add new test suites here as tests here are not isolated from the monorepo.
- unit: These are very fast tests that should run without a browser or running next and should be testing a specific utility.
For the e2e, production, and development tests the createNext utility should be used and an example is available here. This creates an isolated Next.js install to ensure nothing in the monorepo is relied on accidentally causing incorrect tests.
All new test suites should be written in TypeScript either .ts (or .tsx for unit tests). This will help ensure we catch smaller issues in tests that could cause flakey or incorrect tests.
If a test suite already exists that relates closely to the item being tested (e.g. hash navigation relates to existing navigation test suites) the new checks can be added in the existing test suite.
Best Practices
- When checking for a condition that might take time, ensure it is waited for either using the browser
waitForElementor using thecheckutil innext-test-utils. - When applying a fix, ensure the test fails without the fix. This makes sure the test will properly catch regressions.