Run Jest without code coverage constraint?

Question

I am trying to inspect a single test so I run:

npm test alerts.actionCreators.test.js

The test passes, and then I get a huge printout of code coverage and then a failure for not meeting global standards. Can I skip this part of testing while I focus on the just whether the test passes or fails?

Answer 1

I found a hack that mostly works: --collectCoverageOnlyFrom ''. With this the coverage table will be empty and take only about 5 lines.

Answer 2

I would recommend adding a second test command to your package.json :

{
  "test:watch": "jest --watch-all",
  ...
}

Jest will watch for changes in your tests/implementation and re-run the tests automatically. It should not cover the tests in watch mode.

It's good idea to run a coverage on your code from time to time. To make sure jest excluded code you don't want to cover, make sure to configure your jest config accordingly:

{
  collectCoverageFrom: ["src/**/{!(*.d.ts),}.{ts,js,.tsx,.jsx}"],
  ...
}

More information about jest configuration can be found here.

Answer 3

Just add path to your file in coveragePathIgnorePatterns in you Jest configuration in package.json. See the documentation

Answer 4

If you have coverage thresholds set in your jest config file, then I recommend running:

jest --watch --coverageThreshold '{}'

This will ignore/override the thresholds so that watch doesn't report failing thresholds, since it only knows about coverage for the handful of files that you've changed. This also allows you to run a much smaller number of tests for each change, compared to --watchAll.

You can also pass that in the settings of the VS Code Jest extension.