Test architecture determines how maintainable your test suite is as it grows. Key decisions: where test files live (co-located with source vs separate directory), how shared setup is structured (fixtures, factories, builders), how CI runs tests (parallel workers, caching), and how to prevent test debt accumulation. A well-architected test suite is fast, isolated, and has minimal duplication in setup logic.
Each stage in order — click any step to read what it does.
Co-located test files with shared fixtures.
The trade-offs worth knowing before you build this.
When you hardcode test data in every test file and add a new required field to your model, every test breaks. Factory functions with defaults mean only the factory needs updating.
Without a coverage gate, developers skip writing tests under deadline pressure. Each PR merges with less coverage, and eventually the suite is meaningless. 80% coverage gate keeps debt in check.
Tests that assert toBeTruthy() or toBeDefined() are false coverage — they pass even if the function returns garbage. Review tests for meaningful assertions. A bad test is worse than no test.
Sign in to share your feedback and join the discussion.
