@Override
    public Throwable getThrowable() {
        return exception;
    }
@Test
    public void getThrowable() throws Exception {
        assertThat(promise.getThrowable()).isNull();
        Throwable exception = new OMSRuntimeException("-1", "Test Error");
        promise.setFailure(exception);
        assertThat(promise.getThrowable()).isEqualTo(exception);
    }