AC-757 Fixed PatientRoomDAO tests

[rishabh-997]

Description of what I changed

1. Updated tests for asynchronous behavior
2. Created a render function to test all the fields of entity with minimal code

Issue I worked on

JIRA Issue: https://issues.openmrs.org/browse/AC-757

Checklist: I completed these to help reviewers :)

• My pull request only contains ONE single commit
  (the number above, next to the 'Commits' tab is 1).

• I have added tests to cover my changes. (If you refactored
  existing code that was well tested you do not have to add tests)

• All new and existing tests passed.

• My pull request is based on the latest changes of the master branch.

[f4ww4z]

Great work @rishabh-997