mutant: add INVERT_LOOPCTRL mutation

[alessio-perugini]

Proposed changes

Implement #136 invert loop break/continue

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update (if none of the other choices apply)

Checklist

• I have read the CONTRIBUTING doc
• Lint and unit tests pass locally with my changes (make all)
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)
• Any dependent changes have been merged and published in downstream modules

Further comments

I've added the loop control support. I'm not sure if the fixtures are good enough.
I was wondering what will happen when changing the control results in an infinite loop?

[codecov]

Codecov Report

Merging #159 (120185b) into main (0b8ecb3) will increase coverage by 0.04%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #159      +/-   ##
==========================================
+ Coverage   88.03%   88.07%   +0.04%     
==========================================
  Files          18       18              
  Lines        1295     1300       +5     
==========================================
+ Hits         1140     1145       +5     
  Misses        128      128              
  Partials       27       27              

Flag	Coverage Δ
unittests	88.07% <100.00%> (+0.04%)	⬆️

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

Impacted Files	Coverage Δ
internal/configuration/mutantenabled.go	100.00% <ø> (ø)
internal/engine/node.go	100.00% <100.00%> (ø)
internal/mutator/mutator.go	88.23% <100.00%> (+0.73%)	⬆️

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[k3rn31]

Hello @alessio-perugini, thanks for you PR. I enabled the CI for you.

[alessio-perugini]

@k3rn31 thank you! I run a simple test when the mutant generates an infinite loop and the result is a TIMED OUT. Are we okay with that?

[k3rn31]

@alessio-perugini I'd say it is to be expected in this kind of mutation. It is showing a brittle test case :)

As soon as you mark it as non draft we'll proceed with the review.

[k3rn31]

Thanks again for the PR. Everything looks good.
Since this kind of mutation can produce lots of unbound loops and, consequently, timeouts, it is maybe better to keep it disabled by default.
Could you please fix that and update the documentation accordingly?

Also, since every mutation increases testing times, we decided to keep all the new mutations disabled by default, leaving to the user the decision to enable them on the basis of project necessities. In the future we'll make some statistics to craft a better core set.

[k3rn31]

Everything looks good, I'm going to merge this.