Refactor: Unit test cases for authentication

[VaibhavSingh8]

Issue Description

A few tests are not required and can be removed; the test data is stubbed manually within the methods.

Expected Behaviour

Refactor the tests to take data from fixtures, and remove tests which are not required.

Severity/Priority

• Critical
• High
• Medium
• Low

Additional Information

• I have read and followed the project's code of conduct.
• I have searched for similar issues before creating this one.
• I have provided all the necessary information to understand and reproduce the issue.
• I am willing to contribute to the resolution of this issue.