test: vendor in testify (again)

[acpana]

Signed-off-by: Alex Pana 8968914+acpana@users.noreply.github.com

What this PR does / why we need it:

This patch vendors in:

• testify | MIT LICENSE (directly)
• go-difflib | BSD-3-Clause LICENSE (indirectly)

Also the patch uses testify/require to add some low level unit tests. (I indiscriminately looked for one func/ package w low coverage).

Special notes for your reviewer:

• note we did vendor in testify as per Remove unused stretchr/testify from go.mod #1330 but we may have not been actively using it

Why?

legend: + = pro; - = con

+ I think testify/require and testify/assert are the more expressive frameworks used in OSS go development for testing. eg1.
+ IMO having this dep and using it actively lowers the barrier to entry for contributions when it comes to testing code.
- testify can be a bit heavy (since it contains a few packages)
- it's not without quirks; for instance: https://tychoish.com/post/against-testify/

[codecov-commenter]

Codecov Report

Base: 53.47% // Head: 53.64% // Increases project coverage by +0.17% 🎉

Coverage data is based on head (147b374) compared to base (eb6f434).
Patch has no changes to coverable lines.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2374      +/-   ##
==========================================
+ Coverage   53.47%   53.64%   +0.17%     
==========================================
  Files         117      117              
  Lines       10230    10230              
==========================================
+ Hits         5470     5488      +18     
+ Misses       4341     4325      -16     
+ Partials      419      417       -2     

Flag	Coverage Δ
unittests	53.64% <ø> (+0.17%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...onstrainttemplate/constrainttemplate_controller.go	59.09% <0.00%> (+1.91%)	⬆️
pkg/audit/result.go	100.00% <0.00%> (+100.00%)	⬆️

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[maxsmythe]

LGTM

[sozercan]

minor typo, otherwise LGTM

[ritazh]

Thanks for adding this @acpana! Is the thought that we would start using testify for new unit tests? Is there a need to move existing tests over? when should we use testify vs existing framework?

[acpana]

Is the thought that we would start using testify for new unit tests?

We could! I am a bit opinionated in that I like the expressivity of a require.NoError(// err or call) for instance. I don't feel strongly about this that said. The more interesting angle for me is encouragement/ familiarity for new contributors to gatekeeper who are used to these framework.

Is there a need to move existing tests over?

I don't think there's a need to embark on a wholesale refactor. But I can be convinced otherwise. I've seen code bases that adopted require where there's a mix of "old stuff" and "new stuff". Old stuff gets updated on a refactor/ as needed basis.

when should we use testify vs existing framework?

I think it depends on you (the maintainers) and if you want to encourage the usage. Personally, I'd use require at least for every new test I'd add but that's just preference 🙃 .

[ritazh]

LGTM