Add tests for:
- MockSimilarEditorsClient->getEditor
- MockSimilarEditorsClient->getSimilarEditors
- SimilarEditorsClient->getEditor
- SimilarEditorsClient->getSimilarEditors
Notes
See https://doc.wikimedia.org/cover-extensions/SimilarEditors/MockSimilarEditorsClient.php.html and https://doc.wikimedia.org/cover-extensions/SimilarEditors/SimilarEditorsClient.php.html