function runIterator(arr, method, func, n) { var res = []; var j = 1; var args = [ function() { var pushed = []; for (var i = 0; i < n; i++) pushed[i] = arguments[i]; res[j++] = pushed; return func.apply(this, arguments); } ]; for (var i = 4; i < arguments.length; i++) args[i - 3] = arguments[i]; res[0] = method.apply(arr, args); return res; } return function(name) { var func = Array.prototype[name]; return new UnitTest(name, function () { return typeof func === 'function' }) .add('empty function', function () {match( [ undefined, [4, 3, 2], [undefined, 2, 1], [undefined, 1, 0], ], runIterator([1, 2, 3, 4], func, function() { }, 3), 1 )}) .add('adder', function () {match( [ 10, [4, 3, 2], [7, 2, 1], [9, 1, 0], ], runIterator([1, 2, 3, 4], func, function(a, b) { return a + b; }, 3), 1 )}) .add('sparse array', function () {match( [ 10, [4, 3, 11], [7, 2, 7], [9, 1, 3], ], runIterator([,,,1,,,, 2,,,, 3,,,, 4,,,,], func, function(a, b) { return a + b }, 3), 1 )}) .add('sparse array with one element', function () {match( [ 1 ], runIterator([,,,1,,,,], func, function(v) { return v; }, 3), 1 )}) .add('sparse array with no elements', function () {match( [ undefined ], runIterator([,,,,,,,], func, function(v) { return v; }, 3), 1 )}) .add('initial value and empty function', function () {match( [ undefined, [0, 4, 3], [undefined, 3, 2], [undefined, 2, 1], [undefined, 1, 0] ], runIterator([1, 2, 3, 4], func, function() { }, 3, 0), 1 )}) .add('initial value and adder', function () {match( [ 15, [5, 4, 3], [9, 3, 2], [12, 2, 1], [14, 1, 0] ], runIterator([1, 2, 3, 4], func, function(a, b) { return a + b; }, 3, 5), 1 )}) .add('initial value, sparce array and adder', function () {match( [ 15, [5, 4, 15], [9, 3, 11], [12, 2, 7], [14, 1, 3] ], runIterator([,,,1,,,, 2,,,, 3,,,, 4,,,,], func, function(a, b) { return a + b; }, 3, 5), 1 )}) .add('initial value and sparse array with one element', function () {match( [ 6, [5, 1, 3] ], runIterator([,,,1,,,,], func, function(a, b) { return a + b; }, 3, 5), 1 )}) .add('initial value and sparse array with no elements', function () {match( [ 5 ], runIterator([,,,,,,,], func, function(v) { return v; }, 3, 5), 1 )}); }