First, install the jest library
- 'npm i --save-dev @types/jest'
To run all tests
- 'npm test'
To run all tests with coverage
- 'npm test -- --coverage'
Test integration from api's using a real api endpoint is not the best practice for a unit test purpose, that's why Mock Service Worker MSW DOC
Install
- 'npm install msw@latest --save-dev'
MSW DOC - INTERCEPTING REQUESTS
To avoid api data change on tests we call 'server.close()'
with we need to keep a request with some data as call more than one calls on tests we can just not call 'server.close()'
With we do not want to set the 'server.close' or 'server.resetHandlers()' for every single test we can use the 'beforeAll(server.listen())', 'afterEach(server.resetHandlers())', 'afterAll(server.close())' all this can be set up on the server definition file as it can be defined in the test file as well.
if the npm test is showing the error:
'Warning: ReactDOMTestUtils.act is deprecated in favor of React.act. Import act from react instead of react-dom/test-utils. See https://react.dev/warnings/react-dom-test-utils for more info.'
just type on terminal: 'npm install --save-dev @testing-library/react'
-- find a extension that shows each line that was tested