/vitest

Mocking

Mock boundaries and own their cleanup; prefer dependency injection when it keeps the production interface simpler.

• vi.mock is hoisted. Keep it at file scope (v5 throws otherwise); put handles used by its factory in vi.hoisted. Its specifier must be identical to the production import specifier, and it cannot mock require().
• Create a fresh result from every stateful mock factory per test. Keep one-off module wiring in that file; share only repository-conventional factories.
• Install fake timers before code schedules work. Use async advancement when callbacks schedule promises, and always restore real timers. Do not combine fake timers with uncontrolled real waits. From v5, fake timers and vi.setSystemTime also mock a global Temporal.
• From v5, clearMocks defaults to true: call history is cleared before each test, so assert on calls made inside that test unless the repository sets clearMocks: false.
• Restore owned spies, timers, environment stubs, and replaced global property descriptors in local cleanup. vi.restoreAllMocks() restores vi.spyOn implementations but neither clears their history nor restores automocks; reset or reconfigure automocked exports explicitly.

See the installed version's Vi API for factory, timer, and stub semantics.