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ReScript Test comes with a little retest CLI to help your run your tests.

$ retest 'tests/*.mjs'

Note here that we're using the mjs extension. This gives the runner infer the information about which extension you've specified in your compiler. It can be either of the following:

  • .bs.js
  • .js
  • .mjs
  • .cjs

Testing a single file#

If you're focused on a particular component, you can pass a single test to the CLI:

$ retest tests/MyFile_test.mjs

ES6 modules#

ReScript Test works out of the box with either ES6 modules (starting with Node 14, unfortunately) or CommonJS.


You'll need to use the .mjs extension when using ES6 modules.

This one's on Node 🤷‍♂️.

Recursive directory testing#

If your files are stored in deeper directories, specify the depth that way:

$ retest 'tests/*.mjs' 'test/**/*.mjs'

Enable DOM testing in the CLI#

The CLI comes with a single option, --with-dom, that enables you to opt-in to testing with … a DOM 😄. It activates JSDOM under the hood. JSDOM doesn't come with all the APIs (for instance, it doesn't handle layout), but it's generally enough for testing component logic.

$ retest --with-dom tests/*.mjs