public void testToXmlAttributeValue() throws Exception {
    assertEquals("", XmlUtils.toXmlAttributeValue(""));
    assertEquals("foo", XmlUtils.toXmlAttributeValue("foo"));
    assertEquals("foo&lt;bar", XmlUtils.toXmlAttributeValue("foo<bar"));
    assertEquals("foo>bar", XmlUtils.toXmlAttributeValue("foo>bar"));

    assertEquals("&quot;", XmlUtils.toXmlAttributeValue("\""));
    assertEquals("&apos;", XmlUtils.toXmlAttributeValue("'"));
    assertEquals("foo&quot;b&apos;&apos;ar", XmlUtils.toXmlAttributeValue("foo\"b''ar"));
    assertEquals("&lt;&quot;&apos;>&amp;", XmlUtils.toXmlAttributeValue("<\"'>&"));
  }