@Test
public void throwExceptionIfCircuitBreakerIsOpen_does_nothing_if_circuit_is_CLOSED() {

    // given
    Whitebox.setInternalState(cbSpy, "currentState", State.CLOSED);
    // when
    Throwable cbExplosion = catchThrowable(cbSpy::throwExceptionIfCircuitBreakerIsOpen);
    // then
    assertThat(cbExplosion).isNull();
    verify(cbSpy, times(0)).scheduleHalfOpenStateTimeout();
}