public void FloorTest()
{
int n = 10;
int m = 5;
int[] arr = new int[] { 1, 4, 6, 8, 8, 15, 21 };
Assert.Equal(-1, BinartSearchClass.Floor1(arr, 0));
Assert.Equal(0, BinartSearchClass.Floor1(arr, 1));
Assert.Equal(3, BinartSearchClass.Floor1(arr, 8));
Assert.Equal(4, BinartSearchClass.Floor1(arr, 10));
Assert.Equal(6, BinartSearchClass.Floor1(arr, 25));
}