assertFalse(
          "Should not contain key " + entry.getKey() + " mapped to value " + entry.getValue(),
          equal(getMap().get(entry.getKey()), entry.getValue()));
    }
  }

  private static boolean equal(@Nullable Object a, @Nullable Object b) {
    return a == b || (a != null && a.equals(b));
  }

  // This one-liner saves us from some ugly casts
  protected Entry<K, V> entry(K key, V value) {

                    "msg": "Input should be less than or equal to 100",
                    "input": "150",
                    "ctx": {"le": 100},
                },
                {
                    "type": "greater_than_equal",
                    "loc": ["query", "offset"],
                    "msg": "Input should be greater than or equal to 0",
                    "input": "-1",
                    "ctx": {"ge": 0},

        SnapshotVersion sv1 = addSnapshotVersion(source.getVersioning(), date, artifact);
        // although nothing has changed merge returns true, as the last modified date is equal
        // TODO: improve merge here?
        assertTrue(target.merge(source));
        assertEquals(1, target.getVersioning().getSnapshotVersions().size());

  protected abstract @Nullable Object handleInvocation(
      Object proxy, Method method, @Nullable Object[] args) throws Throwable;

  /**
   * By default delegates to {@link Object#equals} so instances are only equal if they are
   * identical. {@code proxy.equals(argument)} returns true if:
   *
   * <ul>
   *   <li>{@code proxy} and {@code argument} are of the same type

  }

  /**
   * Returns the {@code int} value that, when treated as unsigned, is equal to {@code value}, if
   * possible.
   *
   * @param value a value between 0 and 2<sup>32</sup>-1 inclusive
   * @return the {@code int} value that, when treated as unsigned, equals {@code value}
   * @throws IllegalArgumentException if {@code value} is negative or greater than or equal to
   *     2<sup>32</sup>
   * @since 21.0
   */

  /**
   * Returns true if `other` is a `Headers` object with the same headers, with the same casing, in
   * the same order. Note that two headers instances may be *semantically* equal but not equal
   * according to this method. In particular, none of the following sets of headers are equal
   * according to this method:
   *
   * 1. Original
   * ```
   * Content-Type: text/html
   * Content-Length: 50
   * ```
   *

    }

    @Test
    void testEqualsNullSafe() {
        assertFalse(new Prerequisites().equals(null));

        new Prerequisites().equals(new Prerequisites());
    }

    @Test
    void testEqualsIdentity() {
        Prerequisites thing = new Prerequisites();
        assertTrue(thing.equals(thing), "Expected " + thing + " to equal " + thing);
    }

    @Test
    void testToStringNullSafe() {

    }

    @Test
    void testEqualsNullSafe() {
        assertFalse(new Site().equals(null));

        new Site().equals(new Site());
    }

    @Test
    void testEqualsIdentity() {
        Site thing = new Site();
        assertTrue(thing.equals(thing), "Expected " + thing + " to equal " + thing);
    }

    @Test
    void testToStringNullSafe() {
        assertNotNull(new Site().toString());

    @Test
    void testEqualsNullSafe() {
        assertFalse(new ActivationProperty().equals(null));

        new ActivationProperty().equals(new ActivationProperty());
    }

    @Test
    void testEqualsIdentity() {
        ActivationProperty thing = new ActivationProperty();
        assertTrue(thing.equals(thing), "Expected " + thing + " to equal " + thing);
    }

    @Test
    void testToStringNullSafe() {

    }

    @Test
    void testEqualsNullSafe() {
        assertFalse(new Developer().equals(null));

        new Developer().equals(new Developer());
    }

    @Test
    void testEqualsIdentity() {
        Developer thing = new Developer();
        assertTrue(thing.equals(thing), "Expected " + thing + " to equal " + thing);
    }

    @Test
    void testToStringNullSafe() {