@Test
void invoke_startupMessage_invokesSagaStartupMessage() throws InvocationTargetException, IllegalAccessException {

    // given
    String startMessage = "any string";
    TestSaga saga = new TestSaga();
    saga.createNewState();
    // when
    sut.invoke(createContext(saga, startMessage));
    // then
    assertThat("Expected saga start method to be called.", saga.startupCalled(), equalTo(true));
}