function xmlTest_checkVariableDomValues(variableDom, type, id, text) {
  assertEquals(type, variableDom.getAttribute('type'));
  assertEquals(id, variableDom.getAttribute('id'));
  assertEquals(text, variableDom.textContent);
}
Check the values of the variable DOM.
@param {!Element} variableDom The xml dom of the variable.
@param {!string} type The expected type of the variable.
@param {!string} id The expected id of the variable.
@param {!string} text The expected text of the variable.