michael@0: // Check superficial features of Array.build.
michael@0: 
michael@0: if (getBuildConfiguration().parallelJS) {
michael@0:   load(libdir + "asserts.js");
michael@0: 
michael@0:   var desc = Object.getOwnPropertyDescriptor(Array, "build");
michael@0:   assertEq(desc.configurable, true);
michael@0:   assertEq(desc.enumerable, false);
michael@0:   assertEq(desc.writable, true);
michael@0:   assertEq(Array.build.length, 2);
michael@0:   assertThrowsInstanceOf(() => new Array.build(), TypeError);  // not a constructor
michael@0: 
michael@0:   // Must pass a function to second argument.
michael@0:   for (let v of [undefined, null, false, "cow"])
michael@0:     assertThrowsInstanceOf(() => Array.build(1, v), TypeError);
michael@0: 
michael@0:   // The first argument must be a legal length.
michael@0:   assertThrowsInstanceOf(() => Array.build(-1, function() {}), RangeError);
michael@0: 
michael@0:   // When the this-value passed in is not a constructor, the result is an array.
michael@0:   for (let v of [undefined, null, false, "cow"])
michael@0:     assertEq(Array.isArray(Array.build.call(v, 1, function() {})), true);
michael@0: }