@Test
public void isExceptionACircuitBreakerFailure_returns_whatever_breakingEventStrategy_returns() {

    // given
    Throwable someThrowable = new Throwable();
    BreakingExceptionStrategy falseDecider = ex -> false;
    Whitebox.setInternalState(cbSpy, "breakingExceptionStrategy", falseDecider);
    // expect
    assertThat(cbSpy.isExceptionACircuitBreakerFailure(someThrowable)).isFalse();
    // and given
    BreakingExceptionStrategy trueDecider = ex -> true;
    Whitebox.setInternalState(cbSpy, "breakingExceptionStrategy", trueDecider);
    // expect
    assertThat(cbSpy.isExceptionACircuitBreakerFailure(someThrowable)).isTrue();
}