@Test
public void handle_always_invokesSagaRightAway() throws InvocationTargetException, IllegalAccessException {

    // given
    String message = "theMessage";
    // when
    sut.handle(message);
    // then
    ArgumentCaptor<InvocationContext> captor = ArgumentCaptor.forClass(InvocationContext.class);
    verify(invoker).invoke(captor.capture());
    assertThat("Expected saga instance to be set.", captor.getValue().saga(), instanceOf(Saga.class));
    assertThat("Expected message on invoker context.", captor.getValue().message(), equalTo(message));
}