fail("www..google.com should have been invalid");
    } catch (IllegalArgumentException expected) {
    }
  }

  public void testParentChild() {
    InternetDomainName origin = InternetDomainName.from("foo.com");
    InternetDomainName parent = origin.parent();
    assertEquals("com", parent.toString());

    // These would throw an exception if leniency were not preserved during parent() and child()
    // calls.

    String API_CORS_ALLOW_ORIGIN = "api.cors.allow.origin";

    /** The key of the configuration. e.g. GET, POST, OPTIONS, DELETE, PUT */
    String API_CORS_ALLOW_METHODS = "api.cors.allow.methods";

    /** The key of the configuration. e.g. 3600 */
    String API_CORS_MAX_AGE = "api.cors.max.age";

    /** The key of the configuration. e.g. Origin, Content-Type, Accept, Authorization, X-Requested-With */

      fail("www..google.com should have been invalid");
    } catch (IllegalArgumentException expected) {
    }
  }

  public void testParentChild() {
    InternetDomainName origin = InternetDomainName.from("foo.com");
    InternetDomainName parent = origin.parent();
    assertEquals("com", parent.toString());

    // These would throw an exception if leniency were not preserved during parent() and child()
    // calls.

    public static final String SAME_ORIGIN = "same-origin";
    public static final String ORIGIN = "origin";
    public static final String STRICT_ORIGIN = "strict-origin";
    public static final String ORIGIN_WHEN_CROSS_ORIGIN = "origin-when-cross-origin";
    public static final String STRICT_ORIGIN_WHEN_CROSS_ORIGIN = "strict-origin-when-cross-origin";
    public static final String UNSAFE_URL = "unsafe-url";
  }

     * from the information that is available at the point the problem occurs and as such merely serves as a best effort
     * to provide information to the user to track the problem back to its origin.
     *
     * @return The identifier of the model from which the problem originated or an empty string if unknown, never
     *         {@code null}.
     */
    String getModelId();

    /**