TDD Implementation Skill

Enforce a strict test-driven development cycle: Red → Green → Refactor → Commit.

NEVER

• NEVER write implementation before tests — this is the entire point; skip it and the skill has no value
• NEVER skip mock bootstrap validation — write one mock round-trip test first and confirm it passes before writing 20 tests
• NEVER skip the full test suite run — your file passing is not enough; regressions in unrelated files are your responsibility to notice
• NEVER proceed if tests pass in Red phase — a test that passes before implementation is testing nothing; revise it
• NEVER batch multiple features into one TDD cycle — one behavior change per red-green-refactor loop
• NEVER treat a compile/import error as "red" — tests must fail for the right reason (assertion failure, not broken setup)

Before Writing Any Tests

If mockReset: true in test runner config, most internet mock examples silently fail — return values clear between tests.