Problem/Motivation
Please refer the problem/motivation section of #2737719: EntityResource: Provide comprehensive test coverage: for every entity type, every format, every method
Proposed resolution
Write EntityResourceTestBase subclass for the Feed entity.
Remaining tasks
References
1. Follow-up of #2737719: EntityResource: Provide comprehensive test coverage: for every entity type, every format, every method
2. Subtask of #2824572: Write EntityResourceTestBase subclasses for every other entity type.