* Fails if the selected JSON is not a String or is not present or the value
* is not equal to expected value.
*/
public void isStringEqualTo(String expected) {
isString();
Node node = getNode(actual, path);
if (!node.asText().equals(expected)) {
failWithMessage("Node \"" + path + "\" is not equal to \"" + expected + "\".");
}
}