Testing
We use pytest to test our code.
You can run the current tests from the root directory of the repository by executing:
make test
Testing scopes
We use three testing scopes: unit, integration and end-to-end (e2e).
Unit testing is a testing method by which individual units of source code are tested to determine if they are ready to use, whereas integration testing checks integration between software modules at the boundaries. Lastly, e2e tetsing checks the system as a whole assessing that the functionality expected by the user works as expected and that there are no system errors.
Unit tests should be fast and not relay on unnecessary pieces of code or external dependencies such as databases.
Test-driven development
We try to follow test-driven development (TDD) principles. The methodology is as follows:
- Write the unit and integration tests for the functionality to be implemented.
- Run the tests and check that all of the new tests fail, to ensure that they are actually testing new features.
- Implement a basic version of the required changes for the new tests to pass.
- Check that all (old and new) tests pass.
- Improve the implementation incrementally checking that all tests still pass.
One of this cycles might have subcycles. For example, if you want to add a new high level function for which you write an end-to-end (E2E) test, start writing a test for that function and use small cycles of TDD for the helper functions or dependencies in lower level layers that the new function requires.