Migrating Tests From JUnit 3 (GitAPITesCase) to JUnit 4 (GitAPITest)

[GAyan17]

JENKINS-60940 - Migrating Tests From JUnit 3 (GitAPITesCase) to JUnit 4 (GitAPITest)

Describe the big picture of your changes here to explain to the maintainers why this pull request should be accepted.
If it fixes a bug or resolves a feature request, include a link to the issue.

Tests Migrated in this PR:

• PushTags
• ListBranches
• ListRemoteBranches
• RemoteListTagsWithFilter
• RemoteListTagsWithoutFilter
• CreateTag
• revparse SHA 1 HEAD or Tag
• revparse throws expected exception
• Has Git Repo With Invalid Repo
• Push
• Notes Add First Note
• Notes Append First Note
• Prune
• revlist All
• revlist_
• revlist First Parent
• revlist
• Merge Strategy
• Merge Strategy Correct Fail
• Merge Fast Forward Mode FF
• Merge Fast Forward Mode FF Only

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. This is simply a reminder of what we are going to look for before merging your code.

• I have read the CONTRIBUTING doc
• I have referenced the Jira issue related to my changes in one or more commit messages
• I have added tests that verify my changes
• Unit tests pass locally with my changes
• I have added documentation as necessary
• No Javadoc warnings were introduced with my changes
• No spotbugs warnings were introduced with my changes

Types of changes

What types of changes does your code introduce? Put an x in the boxes that apply

• Test (non-breaking change which updates dependencies or improves infrastructure)

Further comments

• Used GitSampleRepo class for temporary repo directory for the WorkingWithRepo workspace as a Rule, this made easier for creating multiple workspaces as used in some tests.
• Implemented a separate function initializeWorkspace() to initialize the workspace with basic git initialization, also it made initialization of remote and bare workspaces easier.
• Added a separate file GitAPITestForInvalidRepo so that the tests which doesn't need a working workspace can be implemented.