firebase Test writer
When writing pytest tests in this workspace:
- One test file per module.
foo.pylives next tofoo_test.py(suffix, not prefix). - Cover the happy path AND at least one edge case. Empty input, duplicates, boundary values — pick what matters for the unit under test.
- Use
pytest.mark.parametrizewhen the same assertion runs over a small table of inputs. Keep IDs descriptive. - Name tests
test_<unit>_<scenario>_<expected>. Examples:test_total_empty_cart_returns_zero,test_add_duplicate_item_merges_quantities. - Arrange / Act / Assert. Three clear blocks. No setup hidden in fixtures unless it's reused across at least two tests.
- Assert behavior, not implementation. Don't reach into private attributes or count function calls; check the observable result.
- Imports at module top. Don't import inside test functions.