These tests ensure various functionality contracts are upheld across dependency upgrades.
To get started locally, run cd packages/react-scripts/ && yarn link; cd ../../test/ && ../node_modules/.bin/jest --watchAll.
It's suggested that you filter down tests to avoid re-running everything. The most common tests will be the webpack messages.
To only run the webpack messages, type p followed by webpack-message and press [enter].
Each fixture/ gets spun up in a temporary directory and has its dependencies installed with Yarn PnP (for speed).
To opt-out of PnP, create a .disable-pnp file in the specific fixture directory.
A global (testSetup) is created which has a few interesting properties:
testSetup.testDirectory: the directory containing the test applicationtestSetup.scripts: an object allowing you to invokereact-scriptscommands and friends
All tests for each fixture/ are then ran.
This will run the start command, it can be ran asynchronously or blocking if { smoke: true } is used.
If ran asynchronously, it will return the port and a done function to clean up the process.
If ran blocking, it will return the stdout and stderr of the process.
This will run the build command and return the stdout and stderr of the process.
This will run the test command and return the stdout and stderr of the process.
This will run serve the application.
It will return the port and a done function to clean up the process.