public void TestVolume()
{
sphere.Radius = 3;
Assert.Equal(113.10, sphere.Volume(), 2);
sphere.Radius = 108;
Assert.Equal(5276669.29, sphere.Volume(), 2);
sphere.Radius = 6524;
Assert.Equal(1163135916189.84, sphere.Volume(), 2);
sphere.Radius = 1;
Assert.Equal(4.19, sphere.Volume(), 2);
}