code: public ResultMatcher isStringEqualTo(final String expected) {
          return new AbstractResultMatcher(path, configuration) {
              public void doMatch(Object actual) {
                  isString(actual);
                  Node node = getNode(actual);
                  if (!node.asText().equals(expected)) {
                      failWithMessage("Node \"" + path + "\" is not equal to \"" + expected + "\".");
                  }
              }
          };
  
      }
docs: Fails if the selected JSON is not a String or is not present or the value
  is not equal to expected value.