Instruction file imported from ImDjinn/Copilot-Optim (.github/instructions/testing.instructions.md). Copyright stays with the author.

Testing Guidelines

Tests are deterministic controls — they either pass or fail, with no ambiguity. This is their primary value in an agentic workflow: a failing test resets agent accuracy to near 100% at each step.

Rules

• Every new behavior must have a test before the implementation is considered done.
• Tests must be isolated: no shared mutable state between test cases.
• Test the behavior, not the implementation. Avoid testing private internals.
• A test that never fails is not a test — verify it fails before the fix is in place.

Structure

• Unit tests: one assertion per test case where possible.
• Integration tests: cover the contract between components, not internal details.
• Name tests descriptively: should <behavior> when <condition>.

Agent Guard Rails

• After each implementation step, run the full test suite.
• If any previously passing test breaks, stop and fix it before continuing.
• Do not suppress, skip, or comment out failing tests to make the suite pass.
• Security scanners and linters are also deterministic controls — run them as part of the same guard rail loop.