LayoutTests/fast/js/script-tests/delete-syntax.js

   1 description(
   2 "This test checks whether various forms of delete expression are allowed."
   3 );
   4
   5 window.y = 0;
   6
   7 shouldBeTrue('delete x');
   8 window.x = 0;
   9 window.y = 0;
  10 shouldBeTrue('delete window.x');
  11 window.x = 0;
  12 window.y = 0;
  13 shouldBeTrue('delete window["x"]');
  14 window.x = 0;
  15 window.y = 0;
  16 shouldBeTrue('delete (x)');
  17 window.x = 0;
  18 window.y = 0;
  19 shouldBeTrue('delete (window.x)');
  20 window.x = 0;
  21 window.y = 0;
  22 shouldBeTrue('delete (window["x"])');
  23 window.x = 0;
  24 window.y = 0;
  25 shouldBeTrue('(y, delete x)');
  26 window.x = 0;
  27 window.y = 0;
  28 shouldBeTrue('delete ((x))');
  29 window.x = 0;
  30 window.y = 0;
  31 shouldBeTrue('delete ((window.x))');
  32 window.x = 0;
  33 window.y = 0;
  34 shouldBeTrue('delete ((window["x"]))');
  35 window.x = 0;
  36 window.y = 0;
  37 shouldBeTrue('delete (y, x)');
  38 window.x = 0;
  39 window.y = 0;
  40 shouldBeTrue('delete (true ? x : y)');
  41 window.x = 0;
  42 window.y = 0;
  43
  44 shouldBeTrue('delete nonexistent');
  45 shouldBeTrue('delete window.nonexistent');
  46 shouldBeTrue('delete window["nonexistent"]');
  47 shouldBeTrue('delete (nonexistent)');
  48 shouldBeTrue('delete (window.nonexistent)');
  49 shouldBeTrue('delete (window["nonexistent"])');
  50
  51 shouldBeTrue('delete "x"');
  52 shouldBeTrue('delete (2 + 3)');
  53
  54 var mathCos = Math.cos;
  55 delete Math.sin;
  56 Math.tan = null;
  57 // Try deleting & overwriting static properties.
  58 shouldBe("Math.cos", "mathCos");
  59 shouldBe("Math.sin", "undefined");
  60 shouldBe("Math.tan", "null");
  61
  62 var regExpPrototypeCompile = RegExp.prototype.compile;
  63 RegExp.prototype.test = null;
  64 Object.preventExtensions(RegExp.prototype);
  65 delete RegExp.prototype.exec;
  66 // Reverse order of delete & overwrite, tests delete after preventExtensions.
  67 shouldBe("RegExp.prototype.compile", "regExpPrototypeCompile");
  68 shouldBe("RegExp.prototype.exec", "undefined");
  69 shouldBe("RegExp.prototype.test", "null");
  70
  71 // Check that once a property is deleted its name is removed from the property name array.
  72 delete Object.prototype.__defineSetter__;
  73 shouldBe("Object.getOwnPropertyNames(Object.prototype).indexOf('__defineSetter__')", "-1");
  74