refactor phase/extender_test.go

[phil9909]

Summary

Refactor phase/extender_test.go as suggested in #1276 (comment)

Context

In #1276 we duplicated most of the test code in phase/extender_test.go, basically doing the same tests twice, once for Platform API 0.12 and once for 0.13. The API versions expect a different folder layout, which requires changes to the test setup. The reduce the size of phase/extender_test.go, I:

• moved the code to create the folder layout into a helper function (it will check for the Platform API version and behave differently based on that)
• added a loop around the test cases looping over API versions.

Now we have every tests only once in code, while still being executed twice.

The drawback: The helper function is quite complex (especially for test code).

A middle ground could be to keep the loop, but to the Platform API version switch in every test case.

@natalieparellano WDYT?

[natalieparellano]

@phil9909 thanks a lot for this! Despite the complexity of prepareDockerfile I think this will make our lives a lot easier. I added a comment suggestion to hopefully make it friendlier for newcomers.

[phil9909]

Added your suggestions. Thanks for the quick review.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 64.57%. Comparing base (92bb4fb) to head (840b035).
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1297      +/-   ##
==========================================
- Coverage   64.65%   64.57%   -0.08%     
==========================================
  Files         101      101              
  Lines        6949     6984      +35     
==========================================
+ Hits         4492     4509      +17     
- Misses       2051     2064      +13     
- Partials      406      411       +5     

Flag	Coverage Δ
os_linux	64.04% <ø> (-0.07%)	⬇️
os_windows	56.61% <ø> (-0.29%)	⬇️
unit	64.04% <ø> (-0.07%)	⬇️

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