Tried to get SISTRIX tests running; currently fails to mock hasApiKey
we can only mock with the class reference static
add group to sistrix tests
fix sistrix mocking
fix the case that we have valid json but no valid result
rename assert file and add null result for ApiRequest
add assert files for getCredits
add more test
Merge pull request #1 from ClemensSahs/hotfix/sistrix-wip

fix mocking problem
Merge pull request #2 from ClemensSahs/hotfix/sistrix-wip-more-test

add more test
Fix typo in markTestIncomplete