Refactor and Simplify Main Unit Tests

[jlvoiseux]

Motivation / Summary

This PR resolves #179, and contains changes that were taken out of #191 for focus purposes.

Changes

24a5a89 remove testify.Suite in favor of self-sufficient tests, whose teardown is handled by T.Cleanup()
7129e46 uses assert.Contains as intended by remove useless boolean assertions

Older commits are irrelevant, as they were merged as part of #191

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• Start Time: 2022-06-01T11:40:47.477+0000

• Duration: 7 min 3 sec

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Test	Results
Failed	0
Passed	196
Skipped	4
Total	200

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[axw]

LGTM overall, just a few other small things which I think we can tidy up. Generally, we should probably be using T.Setenv instead of os.Setenv directly.

[jlvoiseux]

Thanks for the review @axw ! I have implemented your recommendations in ecdc5f0.

[axw]

LGTM, thanks :)