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 // Check superficial features of Array.build.

 if (getBuildConfiguration().parallelJS) {

   load(libdir + "asserts.js");

   var desc = Object.getOwnPropertyDescriptor(Array, "build");

   assertEq(desc.configurable, true);

   assertEq(desc.enumerable, false);

   assertEq(desc.writable, true);

   assertEq(Array.build.length, 2);

   assertThrowsInstanceOf(() => new Array.build(), TypeError);  // not a constructor

   // Must pass a function to second argument.

   for (let v of [undefined, null, false, "cow"])

     assertThrowsInstanceOf(() => Array.build(1, v), TypeError);

   // The first argument must be a legal length.

   assertThrowsInstanceOf(() => Array.build(-1, function() {}), RangeError);

   // When the this-value passed in is not a constructor, the result is an array.

   for (let v of [undefined, null, false, "cow"])

     assertEq(Array.isArray(Array.build.call(v, 1, function() {})), true);

 }