Write tests that cover edge cases and realistic variations, not just the simplest happy path. For example, when testing a SQL validation rule for forbidden columns, also test wildcard selects (SELECT * FROM request_response_rmt) and nested/sub-queries, since these are common ways the restriction could be bypassed. Likewise, avoid encoding test assertions around behavior that is explicitly expected to change soon (e.g., asserting a specific “default provider” when more providers are about to be added) — such tests become misleading or flaky almost immediately; either remove them, mark them clearly as temporary, or assert on the stable invariant instead of the volatile implementation detail. Finally, keep test code itself maintainable: use explicit, stricter types for test helper parameters and return values (avoid any) so test utilities stay reliable and easy to refactor as the suite grows.