Add IMetadataRepository.removeReferences()

[HannesWell]

In order to allow removing references to other repositories from an IMetadataRepository, just like one can also remove IUs, this adds an IMetadataRepository.removeReferences(Collection) method and implements it in all classes that also implement IMetadataRepository.addReferences().

I have not yet added them, but a little test-case, at least for the most imporant implementation LocalMetadataRepository would probably be good.

[github-actions]

Test Results

       9 files  +       9         9 suites  +9   38m 27s ⏱️ + 38m 27s
2 177 tests +2 177  2 173 ✔️ +2 173    4 💤 +  4  0 ❌ ±0 
6 621 runs  +6 621  6 610 ✔️ +6 610  11 💤 +11  0 ❌ ±0 

Results for commit c28c0a0. ± Comparison against base commit 3bac97b.

♻️ This comment has been updated with latest results.

[HannesWell]

I have not yet added them, but a little test-case, at least for the most imporant implementation LocalMetadataRepository would probably be good.

After thinking about that again, a test case would be quite trivial and just test that a collection would not contain elements anymore after they have been removed. Such trivial tests are usually not necessary.

Therefore I consider this ready. Any other opinions?

[merks]

I personally don't think trivial test cases are needed.

[laeubi]

a test case would be quite trivial

If its trivial it should be trivial to add it, no? :-D

[HannesWell]

a test case would be quite trivial

If its trivial it should be trivial to add it, no? :-D

It is. :) But testing trivial things just to increase the test-coverage also does not bring much value.
Anyway I now added tests for addReferences() and removeReferences() of LocalMetadataRepository.

Furthermore I made the LocalMetadataRepository.repositories a LinkedHashSet to ensure a stable order of repository references, which simplifies manual inspection of the generated content.xml files (technically there is no benefit).