Unit/Integration Tests

[hbusul]

We are missing tests for the REST API.

• Add tests
• Add test coverage
• Add Github workflow so that when a new commit is pushed, tests are run automatically.

[emrdagkusu]

We need to add tests for auto-validated attributes by pydantic. For example, if we give 8 for the "day" attribute in the AbsenceModel, it should return 422 Unprocessable Entity and a message.

Example Models:

class AbsenceModel(BaseModel):
    week: int = Field(..., ge=0)
    day: int = Field(..., ge=0, le=4)
    hour: int = Field(..., ge=0, le=15)
    isLab: int = Field(..., ge=0, le=1)

class LessonModel(BaseModel):
    id: PyObjectId = Field(default_factory=PyObjectId, alias="_id")
    name: str = Field(..., min_length=1)
    instructor: str = Field(..., min_length=1)
    absenceLimit: int = Field(..., ge=0)
    slots: List[SlotModel] = Field(...)
    absences: List[AbsenceModel] = []