Refactor test_api to use pytest regression plugin #232
Description
Is your feature request related to a problem? Please describe.
As a developer, when I add new functionality or change the default behaviour, it is awkward to update the API test
Describe the solution you'd like
Implement the pytest regression test framework for the end-to-end regression tests
Describe alternatives you've considered
Current functionality works but is more clunky and doesn't follow standard practice
Additional context
There may be more than one regression testing framework so check which to use
DoD: The most suitable regression testing framework (e.g., pytest-regressions or similar) is selected after evaluating available options. The chosen framework is installed and configured in the project (e.g., added to requirements and test setup). Existing end-to-end regression tests are migrated to use the new framework, or new regression tests are implemented using it.