chimera-test-the-wiring-not-the-class

Trigger

You built a component that production reaches indirectly: through a factory, a registry, a plugin loader, a config flag, a router, a CLI entrypoint, a dependency-injection container. Your tests construct it directly and call its methods.

Every one of those tests can pass while the component is unreachable in the running system — because nothing in them exercises the registration, the default value of the flag, or the branch in the assembler that decides whether to include it at all.

It does not apply to a pure function that callers import and call directly. There, the import is the wiring, and a unit test covers it. It also does not apply when you are deliberately testing an algorithm in isolation — those tests are correct and should stay; this card says they are not sufficient on their own.

Do

1. Name the entrypoint a user actually hits: the CLI subcommand, the HTTP route, the agent's run loop, the scheduled job. Write it down before writing the test.

2. Write at least one test that starts there and passes no constructor arguments for your component. If the test has to name your class to make the feature happen, it is not testing the wiring.

3. Build the object the way production builds it — call the real factory or config loader:

   # WRONG — proves the class, not the wiring: the component is handed to the thing under test,
   # so the test passes whether or not anything in production ever hands it over.
   assert "reminder" in render(feature=Feature(text="reminder"))
   
   # RIGHT — build it the way the entry point builds it, then look for the same observable
   assert "reminder" in build_the_real_way(config).render()
   

   Chimera's own case is worth naming because the class was never broken. Skill cards had a working retriever, a working store and a working injector — and chimera/config.py:244 reads skill_cards: bool = Field(default=False, ...), so on a stock deployment nothing was ever injected. Every unit test passed. The measurement that eventually caught it counted skills minted against skills injected and found 39 against zero.