useLogin.test.tsx

it("should reset the user information after a subsequent unsuccessful login", async () => {
  // given: The first login attempt was sucessful
  const { result } = renderHook(() => useLogin());

  act(() => result.current.onLogin("admin", "admin"));

  await waitFor(() => expect(result.current.isLoginError).toBeFalsy());
  await waitFor(() => expect(result.current.loggedInUsername).toEqual("admin"));

  // when: login in again with invalid credentials
  act(() => result.current.onLogin("admin", "incorrect-password"));

  // then:
  await waitFor(() => expect(result.current.isLoginError).toBeTruthy());
  await waitFor(() => expect(result.current.loggedInUsername).toBeUndefined());
});