How to separate unit and integration/long running tests on Jest?

Question

Currently, I have two folders: __tests__ for unit (fast) tests and __integration__ for slow tests.

Then, in package.json:

{
  "scripts": {
    "test": "jest",
    "test:integration": "jest -c '{}'",
    ...
  },
  "jest": {
    "testPathIgnorePatterns": ["/node_modules/", "__integration__"]
  }
}

So, when I want to do TDD, I'm running just npm test and when I want to test the entire project, npm run test:integration.

As Jest is offered as a "no configuration" test framework, I was thinking if there's a better (or proper) way to configure this.

Thank you.

Answer 1

Quoting from this post.

You can try name files like:

index.unit.test.js and api.int.test.js

And with Jest’s pattern matching feature, it makes it simple to run them separately as well. For unit testing run jest unit and for integration testing run jest int.

File structure/location you can define based on your preferences as the pattern matching based on the file name is how jest knows what to run.

Also see jest cli documentation about npm scripts:

If you run Jest via npm test, you can still use the command line arguments by inserting a -- between npm test and the Jest arguments

Answer 2

Have you tried jest --watch for TDD? It runs only files related to your git changes, runs errors first and heavily utilise cache for speed.

Other than that, jest -c accepts a path, not a string. You should be good with jest -c jest-integration-config.json, provided that jest-integration-config.json sits in your project's root.