Integration testing

Integration testing is a testing method where multiple parts of the application are tested together. Integration tests are generally more helpful than unit tests, and most application tests should be integration tests.

Integration tests are more valuable because they can give more confidence in our application since we are testing the functionality of different parts, the relationship between them, and how they communicate.

For integration testing, we will use Jest and the React Testing Library. This is a great approach to testing features of the application in the same way the user would use it.

In src/testing/test-utils.ts, we can define some utilities we can use in our tests. We should also re-export all utilities provided by the React Testing Library from here so that we can easily reach out to them whenever they are needed in our tests. Currently, in addition to all the functions provided by the React Testing Library, we are also exporting the following...