text: /*
   * Copyright (c) André Bargull
   * Alle Rechte vorbehalten / All Rights Reserved.  Use is subject to license terms.
   *
   * <https://github.com/anba/es6draft>
   */
  const {
    assertThrows, assertFalse
  } = Assert;
  
  // 15.17.3: WeakSet.prototype methods need to test input value is Object
  // https://bugs.ecmascript.org/show_bug.cgi?id=1686
  
  let ws = new WeakSet();
  assertThrows(TypeError, () => ws.add(0));
  assertFalse(ws.has(0));
  assertFalse(ws.delete(0));
  