Speeding up the test suite

There are not many tests in the actual application, but they’re all pretty fast. While your project will grow, the tests will become more and more time-consuming and more annoying to run. It is not uncommon to have a test suite that runs in a span of 15 minutes, but that is too much time! Now, we are going to see how to speed up a test run to avoid a situation like this, by parallelizing the tests’ executions and evaluating the pitfall this technique carries.

Running tests in parallel

To improve our test run, we need to update the test script in package.json:

"test": "tap test/**/**.test.js",

The npm test command will execute all the files in the test/ folder that ends with the test.js suffix. The cool thing is that each file runs in parallel on a dedicated Node.js process! That being said, it hides some considerations you must be aware of when writing tests:

• process.env is different for every test file...