A canary that only tests the easy case manufactures confidence and is worse than none.

  1. 01

    Stub. Present, scheduled, does no work.

  2. 02

    False completion. Reports done while coverage never converges.

  3. 03

    Blinded by join. Runs, evaluates nothing, because its join returns zero rows.

  4. 04

    Absorbed. Fires correctly into a channel that tolerates it.

  5. 05

    Watcher watches the wrong thing. Monitoring points at the safe components while the dangerous ones run unobserved.

  6. 06

    Inverted instrument failure. The guard fails exactly on the cases it exists to catch.

  7. 07

    Fail toward harm. The instrument does not merely fail, it directs the wrong outcome.