    @Test
    public void testOnChange() throws Exception
    {

        SingleLineText singleLineText = new SingleLineText();
        TextContent textContent = new TextContent(singleLineText);
        TestingRefreshContent testingRefreshContent = new TestingRefreshContent();
        testingRefreshContent.setAsParent(textContent);

        assertEquals(0, testingRefreshContent.refreshUpCount);
        assertEquals(0, testingRefreshContent.refreshDownCount);

        singleLineText.setText("test");
        assertEquals(1, testingRefreshContent.refreshUpCount);
        assertEquals(0, testingRefreshContent.refreshDownCount);
    }