Troubleshooting while writing tests

Troubleshooting while writing tests.md

Some notes

1. Casa already has a working document for writing tests, please check it out if you haven't yet: Unit test cases guideline
2. Since the how-to's of writing tests are covered there, this one will focus on the things/errors you might run into, and what to do with them. We'll use examples from Samarpan codebase

Troubleshooting writing tests

1. Debugging basics

• We have screen.debug(), screen.logTestingPlaygroundURL()
• Notice that sometimes the logs get cut off/are truncated — use DEBUG_PRINT_LIMIT=10000 npm run unit /path here/ to display the whole log
• You can keep console.log in the components themselves — they will log when tests run

2. What to do when component doesn’t render

• What does screen.debug() say?
• Are there any API calls in the component you need to await for?
  • Mock the API calls, then await waitFor(() => expect(spy).toHaveBeenCalled())
  • Or, you can find an element that only shows up once the APIs are done, like:

  const successNotification = await screen.findByTestId('notification-success')
  expect(successNotification).toBeInTheDocument()
  expect(successNotification).toHaveTextContent('API has loaded')
  

3. What to do when component renders but data did not load

• Again — are there any API calls in the component you need to await for?
• What does console.log(data/state) say?

4. Checking if state changes work (local or redux)