Add support for running tests & pushing test-coverage metrics

[vharsh]

Code Coverage is a metric to see how much of the code by means of entities viz statements, branches, functions, etc run when the tests are run. It is a good metric to see how much of the business logic is tested(the expected & actual values are checked assuming no other measurable side effect) & it helps ensure that an existing functionality does not break when newer ones are added or older ones are refactored. While it's not the absolute metric of code quality, a higher code coverage usually implies well written code with minimal side-effects.

Currently tests are to be written down(tracked @ #49), so it'd be great

• to run them on every Pull-Request & PR merge(I believe that'd be push/comm
• to have informational alerts about them going UP/DOWN when PRs are raised, so that people feel encouraged to write tests(automatically managed by CodeCov), as we are ramping up unit-testing, it might not be a very good idea for the CI to fail because code coverage is less than some X%
• to have badges on README.md, badges are cool 🎉

Good starting research points:

• CodeCov is a go-to tool for many projects, but are there any alternatives which might be better?
• Is it better to use the CodeCodv bash exporter or the CodeCov github action, if codecov is the choice of tool?
• Likewise, should running UTs be a workflow separate from the workflow which runs code Linters(GolangCI-Lint)?

Good starting points:

• GitHub actions docs
• OpenEBS NDM example to run tests & upload to CodeCov

Great readings:

• How does the code coverage even work in Golang
• How much code-coverage?

[ParthS007]

After going through the readings

• I think using CodeCov will be good because of good support and customization options.
• We can use either
  • Codecov official site mentions use of bash export.
  • Codecov action mentions use of Github Actions
• We can rename GolangCI-Lint to GolangCI-Test which will include Lint and Unit testing both.

Please let me know what do you think? @vharsh

[vharsh]

1. Thanks for the research, let's stick to codecov. On the bash uploader vs GH marketplace action do whichever is easier.
2. Let's keep linting and unit testing separate, it might help actions/checkout cache results better and it might help understand what failed without looking at the logs.