public void RepeatTest()
{
IEnumerable <int> expected = new int[] { 1, 1, 2, 3, 1, 1, 2, 3, 1, 1, 2, 3, 1, 1, 2, 3 };
IEnumerable <int> actual = LinqTool.Repeat(new int[] { 1, 1, 2, 3 }, 4);
Assert.IsTrue(expected.SequenceEqual(actual));
}