[TEST] Implement JUnit Testing for Instrumental and Local Testing

[youssef-ahmmed]

For Instrumental

Testing should be done for the following modules:

• Dao
• Database

For Local

Testing should be done for the following modules:

• ViewModel
• Entity
• Repository

Standard Annotation for testing methods

• Format: methodName_scenario_expectedResult
• Explain:
  1. methodName: refers to the method being tested.
  2. scenario: refers to the test scenario being tested.
  3. expectedResult: refers to the expected outcome of the test.