This PR updates the testing guides to use App Router and TypeScript,
also updates `/examples` to show `app` and `pages` examples.
## Overview
- [x] Create a new "Testing" section that is shared between `app` and
`pages`.
- [x] Explain the differences between E2E, unit testing, component
testing, etc.
- [x] Recommend E2E for `async` components as currently none of the
tools support it.
- [x] Update setup guides for **Cypress**, **Playwright**, and **Jest**
with latest config options, and examples for `app` and `pages`.
- [x] Add new guide for **Vitest**
- [x] Clean up `/examples`: use TS, show `app` and `pages` examples,
match docs config
## Cypress
- [x] E2E Tests
- [x] Component Testing
- [x] Client Components
- [x] Server Components
- [ ] `async` components
**Blockers:**
- TS: `Option 'bundler' can only be used when 'module' is set to
'es2015' or later`. In **tsconfig.json** compilerOptions, Next.js uses
"moduleResolution": "bundler", changing it to "node" fixes the issue but
it can have repercussions.
- https://github.com/cypress-io/cypress/issues/27731
- Version 14 is currently not supported for component testing
- https://github.com/cypress-io/cypress/issues/28185
## Playwright
- [x] E2E Tests
## Jest
- [x] Unit Testing
- [x] Client Components
- [x] Server Components
- [ ] `async` components:
https://github.com/testing-library/react-testing-library/issues/1209
- [x] 'server-only': https://github.com/vercel/next.js/pull/54891
- [x] Snapshot Testing
**Blockers:**
- TS: https://github.com/testing-library/jest-dom/issues/546
- None of the solutions in the issue work with Next.js v14.0.4 and TS v5
## Vitest
- [x] Unit Testing
- [x] Client Components
- [x] Server Components
- [ ] `async` components
- [x] 'server-only'
- [x] Update vitest example
- [x] Handles CSS, and CSS modules imports
- [x] Handles next/image
## Other
- https://github.com/vercel/next.js/issues/47448
- https://github.com/vercel/next.js/issues/47299
Ref: https://github.com/vercel/next.js/issues/36842, https://github.com/vercel/next.js/pull/36632, https://github.com/vercel/next.js/pull/36787
Upgrading to Jest 28, and aligning Babel example with `with-jest`
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [ ] Make sure the linting passes by running `yarn lint`
The `with-jest` example has been converted to TypeScript (#32705) , but `typescript` and `@types/react` were missing from `devDependencies`
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [ ] Make sure the linting passes by running `yarn lint`
* chore: convert Jest examples to TypeScript
* test: use absolute imports in test files
* chore: address review comments
* fix: add pages to tsconfig.json paths
* fix: add styles to tsconfig.json paths
* chore: upgrade dependencies/snapshots
* docs: match Testing docs with example code
* docs: link to docs from mock test files
Co-authored-by: Lee Robinson <me@leerob.io>
* Use recommended pattern in testing example
Since the official linter for testing library, `eslint-plugin-testing-library` recommends using `screen` to write queries, this MR updates the testing library example to follow the pattern recommended by the linter.
> DOM Testing Library (and other Testing Library frameworks built on top of it) exports a screen object which has every query (and a debug method). This works better with autocomplete and makes each test a little simpler to write and maintain.
> This rule aims to force writing tests using built-in queries directly from screen object rather than destructuring them from render result. Given the screen component does not expose utility methods such as rerender() or the container property, it is correct to use the render returned value in those scenarios.
See the `prefer-screen-queries` rules docs for more info: https://github.com/testing-library/eslint-plugin-testing-library/blob/main/docs/rules/prefer-screen-queries.md
* Update devDependencies
* Install and configure test linting
* Use recommended pattern in test
* Update test names for consistency
* Update docs
* Set jest environment in each file
* Use root true in `with-jest` eslint config
* Ensure nested .eslintrcs are not loaded for repo lint
Co-authored-by: jj@jjsweb.site <jj@jjsweb.site>
* Add licences to all example/package.json that lack them
* Revert "Add licences to all example/package.json that lack them"
This reverts commit 5d4e25012f7334772b8ef5924bc355277e827cba.
* Update check-examples to remove `license` field from examples
* Remove `license` from all examples.
This was mentioned in vercel/next.js#27121 but it looks like it didn't end up being in the merge?
Co-authored-by: JJ Kasper <jj@jjsweb.site>
Clean up package.json files in the `examples` directory:
- Add `private: true`
- Remove `version` (because they are irrelevant for packages that are not meant to be published)
- Remove `name` (because they are optional for packages that are not meant to be published, and when someone clones an example, they often rename it and the property becomes stale)
- Remove `author`
- Remove `description`
- Remove `license`
Also remove `with-dynamic-app-layout` example completely, since it does the same as `layout-component` (https://github.com/vercel/next.js/pull/27121#discussion_r668178408).
## Documentation / Examples
- [x] Make sure the linting passes
npm i wasn't working because of outdated version of react-test-renderer.
## Bug
- [X] Related issues linked using `fixes #number`
- [ ] Integration tests added
## Feature
- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
## Documentation / Examples
- [ X] Make sure the linting passes
[With next 11 requiring react 17](https://nextjs.org/blog/next-11#upgrade-guide), most of the examples
need to be updated, so the following snippet updated all the examples to
a compatible react version.
```bash
cd examples/
fd -g 'package.json' | xargs sed -r -i 's/"react": ".*"/"react": "^17.0.2"/
fd -g 'package.json' | xargs sed -r -i 's/"react-dom": ".*"/"react-dom": "^17.0.2"/'
# exclude experimental react version
git checkout with-reason-relay/package.json
```
The latest version of babel-jest doesn't require `babel-core` with the bridge version anymore (updated in this PR : https://github.com/facebook/jest/pull/7016).
So I'm updating with-jest and with-jest-react-testing-library examples accordingly.
I changed the version to the following files:
- [x] - examples/with-next-css/package.json
- [x] - examples/with-draft-js/package.json
- [x] - examples/custom-server-polka/package.json
- [x] - examples/with-cerebral/package.json
- [x] - examples/with-zones/package.json
- [x] - examples/with-universal-configuration-runtime/package.json
- [x] - examples/with-apollo/package.json
- [x] - examples/with-higher-order-component/package.json
- [x] - examples/with-hashed-statics/package.json
- [x] - examples/with-pkg/package.json
- [x] - examples/with-jest/package.json
- [x] - examples/with-glamorous/package.json
- [x] - examples/with-custom-reverse-proxy/package.json
- [ ] - examples/with-emotion/package.json
- [x] - examples/with-styled-jsx-scss/package.json
- [x] - examples/with-styled-jsx-plugins/package.json
`with-emotion/package.json` already has the latest, so I guess it's other packabe. BUT I think we need to update this example with the latest version of `emotion` since it changed a little bit (for better).
Running the [with-jest](https://github.com/zeit/next.js/tree/canary/examples/with-jest) example results in the following error:
```log
FAIL __tests__/index.test.js
● Test suite failed to run
SecurityError: localStorage is not available for opaque origins
at Window.get localStorage [as localStorage] (node_modules/jsdom/lib/jsdom/browser/Window.js:257:15)
at Array.forEach (<anonymous>)
Test Suites: 1 failed, 1 total
Tests: 0 total
Snapshots: 0 total
Time: 0.943s
Ran all test suites.
error Command failed with exit code 1.
```
Upgrading the dependencies (jest) to the latest version helps!
[More info](https://github.com/jsdom/jsdom/issues/2304)
Related #4776
babel-jest is included automatically by jest when a babel config is present, so including it manually here doesn't do anything.
> "Note: babel-jest is automatically installed when installing Jest and will automatically transform files if a babel configuration exists in your project."
http://facebook.github.io/jest/docs/en/getting-started.html#using-babel
