MPL-32 Added working implementation of the JenkinsRule unit tests

[sparshev]

TODO:

• [ ] Clarify with Jenkins devs
• [ ] Simplify & clear the logic
• [ ] Make sure migration is simple
• [x] Fix stack indent issue
• [x] Fix issue with tests conflict (#56)
• [ ] Unit tests
• [ ] Documentation

[sparshev]

Nope, we can't use CPS from JenkinsPipelineUnit by default - the implementation contains quite critical issues (for example [1,2,3].findAll { it > 1 } will return false instead of [2,3]), like the one was fixed here: jenkinsci/workflow-cps-plugin#124

[sparshev]

Added another implementation of the CPS tests - based on JenkinsRule with groovy-cps interceptor. This implementation seems working fine mvn clean verify shows almost the same results as the simple JenkinsPipelineUnit tests. But:

• Check with Jenkins devs - how to eliminate this java replacements, maybe they can help with some hooks for the unit tests...
• Need to prepare a good documentation
• Simplify migration from the old test base class MPLTestBase to the new one MPLTestBaseJenkinsRule
• Prepare more tests as examples of usage this new tests
• JenkinsRule instance produces logs I want to hide
• Stack of MethodCall depth is not good - seems something wrong with CpsScript stacktrace (for example last Build.fileExists(openshift) is one level deeper than required... It could be some sort of issue with the Closure in the test).

[sparshev]

Reproduced weird behavior during tests running: when old tests running before new ones - new ones will not be completed:

• old -> new: https://app.circleci.com/jobs/github/griddynamics/mpl/470/ (fail)
• new -> old: https://app.circleci.com/jobs/github/griddynamics/mpl/472/ (success)

Something in the groovy tests is not working well.

[sparshev]

Not weird as figured out - Helper.runModule replaced in the BuildTest, so it's saved for the future tests executions. Need to add restore the overriding classes state.