A comprehensive experience when using Facebook's Jest within a project.
- Useful IDE based Feedback
- Session based test watching
Orta Therox (@orta), Sean Poulter (@seanpoulter), Vincent Voyer (@vvo) & ConnectDotz (@connectdotz).
- Starts Jest automatically when you're in a root folder project with Jest installed.
- Show individual fail / passes inline.
- Show fails inside the problem inspector.
- Highlights the errors next to the
- Adds syntax highlighting to snapshot files.
- A one button update for failed snapshots.
- Show coverage information in files being tested. (requires coverage to be collected by your jest config)
How to get it?
Open up VS Code, go search for the extension "Jest".
How to get it set up?
This project has the expectation that you would run something like
npm run test which just looks like
jest in the
package.json. So, please keep your configuration inside the
package.json as opposed to using command line arguments.
If have a more complex setup, it can probably be supported, check out the settings. They are all prefixed with
Also, you should use Jest 17+, however 16 works - it will just offer a warning. We're aiming to try and do current Jest version - 1, but won't specifically drop support for older versions unless we're forced into it.
How to start the Jest?
The extension will start Jest for you when:
- we find Jest configuration files in the workspace:
- we find Jest installed in the workspace:
- we find the workspace has been bootstrapped with create-react-app:
- you run the Jest: Start Runner command
How do I debug tests?
The simplest use cases should be supported out-of-the-box, but at the latest when VS Code displays errors about the attribute
runtimeExecutable not being available, you have to create your own debug configuration within
This plugin provides blueprints for debugging plain Jest setups or projects bootstrapped by
create-react-app. (In the latter case you may have to edit the
runtimeExecutable to reflect the used
react-scripts package.) If those don't match your setup, you can modify the blueprints or create a completely new debug configuration, but keep in mind, that the
type has to be
node and that the configuration has to be named
"vscode-jest-tests". In order to learn more about debug/launch configurations in general, visit VS Code Docs: Debugging.
Starting with debugging is possible by clicking on the
debug CodeLense above appendant
it tests, but you can also debug all tests at once by starting debugging of
"vscode-jest-tests" within the VS Code Debug Side Bar.
Notes for troubleshooting
In contrast to previous versions of this plugin the debug settings are now independent from VS Code's
jest.pathToConfig setting. If you had to modify one of these, you pretty surely have to create a custom debug configuration and modify its path. This especially includes cases, in which
jest isn't at its default location.
How do I show code coverage?
To show code coverage in the VS Code, you will need to:
I'd like to give a shout out to Wallaby.js, which is a significantly more comprehensive and covers a lot more editors, if this extension interests you - check out that too.
Someone to take responsibility for ensuring that the default setup for create-react-app is always working. All the current authors use TypeScript and React/React Native and so have very little familiarity with changes to CRA. Apply via PRs :D.
start jest from non-root folder
If you don't use the root of your project for your JS with Jest tests, do not worry, you can still use this project. You will need to use the "Start Jest Runner" command, and maybe have to configure your own
jest.pathToJest setting inside the
.vscode/settings.json to whatever you would use.
These are the activation events which trigger the runner to start:
These are the things that will trigger the extension loading. If one of these applies, and you're not seeing the "Jest" in the bottom bar, reference the self-diagnosis below
vscode-jest supports common jest configuration, such as when jest is in
root/node_modules/.bin/jest, or for react-native
However, if your repo doesn't fall into these patterns or you want to pass extra parameters, you can easily use the
jest.pathToConfig settings to instruct the plugin on how to start jest. You can even use the scripts from package.json, such as
npm run test -- or
yarn test. Feel free to experiment and search the issues for many examples.
plugin not running as expect? try self-diagnosis
If your can execute jest tests on command line but vscode-jest was not running as expected, here is what you can do to find out what it is actually doing:
- click on
Jest:stopped on status bar to show Jest Output window:
- turn on the debug mode: set
"jest.debugMode": true in
- restart vscode-jest or reload the window (via
Reload Window command)
- open the developer tool (via
Help > Toggle Developer Tools menu), you should see more information including how we extract jest config and spawn jest processes.
Hopefully most issues would be pretty obvious after seeing these extra output, and you can probably fix most yourself by customizing the
jest.pathToJest and other settings.
Want to Contribute?
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