testInt32ToId.js - mozsearch

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function testInt32ToId()

  // Ensure that a property which is a negative integer that does not fit in a

  // jsval is properly detected by the 'in' operator.

  var obj = { "-1073741828": 17 };

  var index = -1073741819;

  var a = [];

  for (var i = 0; i < 10; i++)

    a.push(index in obj);

    index--;

  // Ensure that a property which is a negative integer that does not fit in a

  // jsval is properly *not* detected by the 'in' operator.  In this case

  // wrongly applying INT_TO_JSID to -2147483648 will shift off the sign bit

  // (the only bit set in that number) and bitwise-or that value with 1,

  // producing jsid(1) -- which actually represents "0", not "-2147483648".

  // Thus 'in' will report a "-2147483648" property when none exists, because

  // it thinks the request was really whether the object had property "0".

  var obj2 = { 0: 17 };

  var b = [];

  var index = -(1 << 28);

  for (var i = 0; i < 10; i++)

    b.push(index in obj2);

    index = index - (1 << 28);

  return a.join(",") + b.join(",");

assertEq(testInt32ToId(),

	 "false,false,false,false,false,false,false,false,false,true" +

	 "false,false,false,false,false,false,false,false,false,false");