### Question:
PromptAdapter implements GriffonPivotAdapter, org.apache.pivot.wtk.PromptListener { public void messageChanged(org.apache.pivot.wtk.Prompt arg0, java.lang.String arg1) { if (messageChanged != null) { messageChanged.call(arg0, arg1); } }  CallableWithArgs<Void> getMessageTypeChanged(); CallableWithArgs<Void> getMessageChanged(); CallableWithArgs<Void> getBodyChanged(); CallableWithArgs<Void> getOptionInserted(); CallableWithArgs<Void> getOptionsRemoved(); CallableWithArgs<Void> getSelectedOptionChanged(); void setMessageTypeChanged(CallableWithArgs<Void> messageTypeChanged); void setMessageChanged(CallableWithArgs<Void> messageChanged); void setBodyChanged(CallableWithArgs<Void> bodyChanged); void setOptionInserted(CallableWithArgs<Void> optionInserted); void setOptionsRemoved(CallableWithArgs<Void> optionsRemoved); void setSelectedOptionChanged(CallableWithArgs<Void> selectedOptionChanged); void messageTypeChanged(org.apache.pivot.wtk.Prompt arg0, org.apache.pivot.wtk.MessageType arg1); void messageChanged(org.apache.pivot.wtk.Prompt arg0, java.lang.String arg1); void bodyChanged(org.apache.pivot.wtk.Prompt arg0, org.apache.pivot.wtk.Component arg1); void optionInserted(org.apache.pivot.wtk.Prompt arg0, int arg1); void optionsRemoved(org.apache.pivot.wtk.Prompt arg0, int arg1, org.apache.pivot.collections.Sequence<?> arg2); void selectedOptionChanged(org.apache.pivot.wtk.Prompt arg0, int arg1);  }### Answer:
@Test public void testMessageChanged() { final boolean[] invoked = new boolean[1]; CallableWithArgs<Void> callable = new CallableWithArgs<Void>() { public Void call(Object... args) { invoked[0] = true; return null; } }; assertNull(adapter.getMessageChanged()); adapter.messageChanged(null, null); assertFalse(invoked[0]); adapter.setMessageChanged(callable); adapter.messageChanged(null, null); assertTrue(invoked[0]); }