public void CalculatePerlin_should_return_the_same_value_for_a_series_of_x_values()
{
var perlin = new Perlin();
double p1 = perlin.CalculatePerlin(0, 0, 0);
double p2 = perlin.CalculatePerlin(1, 0, 0);
double p3 = perlin.CalculatePerlin(2, 0, 0);
double p4 = perlin.CalculatePerlin(3, 0, 0);
p1.Should().Be(p2);
p1.Should().Be(p3);
p1.Should().Be(p4);
}