TDD & Stub-First Strategy

1. Stubbing Phase

1. •Create Structure: Files, classes, methods.
2. •Implement Stubs: Use NotImplementedError, return None, or hardcoded values.
3. •Docstrings: Add detailed docstrings describing future logic.
4. •E2E Test (Stub): Write an E2E test that asserts the hardcoded behavior.
   • •Example: asserting discount == 100.0 (stubbed value).

2. Implementation Phase

1. •Verify Stubs: Ensure E2E test passes on stubs.
2. •Replace Stubs: Implement real logic.
3. •Unit Tests: Add unit tests for specific methods and edge cases.
4. •Update E2E: Update E2E test to assert real behavior.
   • •Example: asserting discount == 150.0 (calculated value).

3. Testing Rules

• •No Mocking LLMs: Use recorded responses or separate integration environments.
• •Regression: Always run full regression suite.