public void CeilTest()
        {
            int[] arr = new int[] { 1, 4, 6, 8, 8, 15, 21 };


            Assert.Equal(0, BinartSearchClass.Ceil(arr, -10000));
            Assert.Equal(0, BinartSearchClass.Ceil(arr, 1));
            Assert.Equal(4, BinartSearchClass.Ceil(arr, 8));
            Assert.Equal(5, BinartSearchClass.Ceil(arr, 10));
            Assert.Equal(-1, BinartSearchClass.Ceil(arr, 25));
        }