tests cleanup user_stories#218
This is the first step in tests review user_stories#218 (closed):
- reorganisation of the namespaces, some tests were moved
- get rid of tests that compare the full API result to a fixed expected result
- small cleanup of test files
In the new world, we still have N sample feed files, and it is still possible to use this small corpus in the test. However, a test using it has to be prepared for changes in the corpus. Ideally, such a test does not require modifications if the corpus changes.
More tests, written according to new rules, will be added in other MRs.