[TECHNICAL] Unit tests for repository classes - Part 1

[JuancaG05]

Epic:

• https://github.com/owncloud/android/issues/4063

In this issue we'll address the unit tests for the classes:

• OCAppRegistryRepository
• OCAuthenticationRepository
• OCCapabilityRepository

Remember we want to create unit tests that check that every method returns the expected result and verify that every method calls the corresponding methods of other classes.

TASKS

• [x] Research (if needed)
• [x] Create branch technical/testing_repositories_1
• [x] Development tasks
  • [x] Create unit tests for OCAppRegistryRepository
  • [x] Create unit tests for OCAuthenticationRepository
  • [x] Create unit tests for OCCapabilityRepository
• [x] Code review and apply changes requested
• [x] Merge branch technical/testing_repositories_1 into master