Here's a breakdown of the factors influencing unit testing decisions:
1. Code Coverage:
* Goal: Aim for high code coverage, especially for critical and complex parts of your code.
* Not a silver bullet: While high coverage is desirable, it doesn't guarantee quality. Tests need to be effective, not just cover lines of code.
2. Code Functionality:
* Prioritize core functionality: Focus on testing the main features and behaviors of your code.
* Consider boundary conditions: Test edge cases and extreme values to ensure robustness.
* Test for errors: Write tests to check for expected exceptions and error handling.
3. Code Complexity:
* More complex code = more tests: Complex logic, intricate algorithms, or heavily coupled modules require more thorough testing.
* Refactoring: Test before and after code changes to ensure functionality is maintained.
4. Business Requirements:
* Align tests with business needs: Ensure tests cover critical business rules and user expectations.
* Consider user stories: Develop tests that reflect the user's perspective and intended use.
5. Test Driven Development (TDD):
* Write tests before code: This approach can drive better design and clearer code.
* Red-Green-Refactor cycle: Write failing tests (red), write code to make them pass (green), then refactor for better design (refactor).
6. Practical Considerations:
* Time and resources: Prioritize testing based on available resources and project deadlines.
* Risk assessment: Focus on areas with higher risk of bugs or critical failures.
* Maintainability: Write tests that are easy to read, understand, and maintain.
In Summary:
There's no one-size-fits-all answer for unit testing entry criteria. Consider the factors above to decide what, when, and how to test. Always prioritize code coverage, functionality, and business requirements, while also being practical about resource allocation and test maintenance.