Best Practices Pytest - Guidelines

Framework: Use pytest as your main framework for tests
Keep Tests Small and Focused: Each test should verify one specific behavior or logic. Avoid testing multiple things in one test case.
Name Tests Clearly: Use descriptive names like test_addition_returns_correct_sum.
Use Setup and Teardown Wisely: Use setUp() and tearDown() (or fixtures in pytest) to prepare and clean up test environments.
Mock External Dependencies: Use unittest.mock or pytest-mock to isolate the unit under test from external systems (e.g., databases, APIs).
Test Edge Cases: Include tests for boundary conditions, empty inputs, large inputs, etc.
Documentation: add a short description about what you are testing
What to cover?:
- Correctness: Does the function return the expected output for valid inputs?
- Edge Cases: What happens with empty lists, None, zero, negative numbers, etc.?
- Error Handling: Does it raise the correct exceptions for invalid inputs?

Here’s a checklist of things to test in a typical Python function or module:

Test Type	What to Check
Correctness	Does the function return the expected output for valid inputs?
Edge Cases	What happens with empty lists, `None`, zero, negative numbers, etc.?
Error Handling	Does it raise the correct exceptions for invalid inputs?
Performance (optional)	Is it fast enough for large inputs? (usually not in unit tests)
Side Effects	Does it modify global state, write to disk, or call external services?
Integration Points	If it interacts with other modules, are those interactions correct?