Fix/add mongomock unittests

[wderocco8]

What does this PR do?

Added more unit tests to the backend and integrated support for MongoDB testing with mongomock library.

Type of change

• Fix: Bug fix (non-breaking change which fixes an issue)
• Refactor: Any code refactoring
• Chore: technical debt, workflow improvements
• Feature: New feature (non-breaking change which adds functionality)
• Documentation: This change requires a documentation update
• Merge: Pushing features to an upper envrironment

Tests Performed

Screenshots

Additional Comments

[github-actions]

☂️ Python Coverage

current status: ✅

Overall Coverage

Lines	Covered	Coverage	Threshold	Status
1811	1357	75%	70%	🟢

New Files

File	Coverage	Status
tests/services/test_event_service.py	100%	🟢
TOTAL	100%	🟢

Modified Files

File	Coverage	Status
chalicelib/modules/mongo.py	24%	🟢
chalicelib/services/EventService.py	26%	🟢
TOTAL	25%	🟢

updated for commit: 3a966a3 by action🐍

[jinyoungbang]

LGTM! Maybe make that one change that I commented. Thank you for the unit tests :)

[jinyoungbang]

Consider using a ternary operator!

def __init__(self, use_mock=False):
    """Establishes connection to MongoDB server"""
    self.mongo_client = mongomock.MongoClient() if use_mock else MongoClient(self.uri)