Unit Tests

Context

The code base is growing and so does the number of functions and custom hooks.

While we have a good coverage in our UI tests from Cypress we are lacking something to tests the inner workings of the applications.

With unit tests added we can test bits of functionality that is shared between different areas of the application and make sure that we get the expected output giving different variations of input.

Decision

We decided to go for Vitest which is an easy to use and very fast unit testing tool.

It has more or less the same capabilities as Jest which is another popular testing framework which is similar.

Vitest is framework agnostic so in order to make it possible to test hooks we found @testing-library/react-hooks that works in conjunction with Vitest.

Alternatives considered

We could have used Jest. But trying that we experienced major problems with having both Jest and Cypress in the same codebase. They have colliding test function names and Typescript could not figure it out.

There is probably a solution but at the same time we got Vitest recommended. It seemed very fast and just as capable as Jest. And we did not have the colliding issues of shared function/object names.

Consequences

We now have unit test as a part of the mix which brings more stability and certainty that the individual pieces of the application work.