textArea.setText("TextComponent Text");
getRobot().waitForIdle();
verify(observer, times(1)).valueChanged(eq("TextComponent Text"), any(String.class));
StringContent content = new StringContent();
content.insertString(0, "TextComponent new Document");
textArea.setDocument(new PlainDocument(content));
getRobot().waitForIdle();
verify(observer, times(1)).valueChanged(eq("TextComponent new Document"), any(String.class));
}