Improve test coverage

[srbarrios]

It would be interesting to review the rspec test and see how we can improve them.
Things in mind:

• Better naming and structure of secondary_spec.rb and secondary2.spec, understanding the reasons behind the current structure
• We currently have features where the list of prs to be processed is important, as sometimes we skip it, sometimes we force one pr. We could try to add more coverage, for instance, checking if we perform more than one context or more than one PR.
• Test the behaviour of force_test and pr_number parameters separately:
  • --PR pr_number should skip the list of pending prs, only processing the specified PR
  • --force_test that will directly run the test for that PR number without check other filters.