Add provider classifier test case

Editor assessment

The subject names the addition — a provider classifier test case — and the body pins the exact contract: isFactoryProvider must return false when useFactory is not present. That behavioral sentence tells readers precisely what the test guards, which is what a test commit should document. test(core) is accurate in both type and scope. No footers are present, and none are needed. Hygiene is clean: imperative subject, lowercase continuation, no trailing period, no pasted content. A compact test message whose body adds real information rather than padding.