code: public static Condition withPostBodyContainingJsonPath(final String pattern, final Object value) {
          return new Condition(input -> value.equals(JsonPath.parse(input.getPostBody()).read(pattern)));
      }
docs: With Valid Json Path.
  Check to see if incoming path has a valid string value selected via a <a href="https://github.com/jayway/JsonPath/">
  JSONPath</a> expression.