./api is auto-mocked with jest.mock('./api'). The component calls fetchUser(id).then(setUser). Which line makes fetchUser resolve with Ana?

mockResolvedValue(x) is short for returning Promise.resolve(x), so fetchUser resolves with Ana. The tempting mockReturnValue and mockImplementation options are wrong. They return a plain object, not a promise. A plain object has no .then, so the component throws. mockRejectedValue is wrong because it makes the promise reject.