The Recommended Pattern for Testing for API Changes

Validating API changes

Applying the three rules for modifying APIs starts at the design phase of our API update. It’s important we take the time to review all the requested changes before moving forward to make our API modifications. It’s important to then implement those design changes faithfully. We also need to validate that our changes won’t break existing API consumers.

Validating API changes involves a few steps:

1. Who is using the API?
2. Validating API changes with existing tests.
3. Confirming API changes with new, standalone tests.

Who is using our API?

This can be tricky business because we don’t always have access to all the API consumer applications or the teams that build them. Within a single organization, we might be able to inspect all the API consumer source code and check for problems.