Testing: Introduce pytest-based automated test suite for MUIO Flask backend

[sairamsharan]

Hi maintainers

The MUIO Flask backend currently does not have an automated testing suite. This makes it harder to confidently refactor code, verify endpoint behavior, and maintain long-term reliability as the project evolves.

Proposed Changes

• Add pytest and pytest-flask as development dependencies

• Create a structured test directory:

  tests/
  ├── conftest.py
  └── test_app.py

• Implement reusable Flask test client fixtures that run the app in TESTING mode without starting the Waitress server

• Add initial unit tests for core endpoints in API/app.py, including:

  • GET / → verify index is served successfully
  • GET /getSession → validate behavior when session is missing
  • POST /setSession → verify valid session persistence flow
  • POST /setSession (invalid payload) → validate error handling

Expected Benefits

• Improves backend reliability
• Enables safer future refactoring
• Provides a foundation for expanding test coverage
• Aligns the project with modern testing best practices

[parthdagia05]

@sairamsharan i was working on automating tests , but i satrted with backend unit tests i have opened a PR #30 , you could review that too