public void Vector3dSubtractsCorrectly()
{
var v = new Vector3d(2, 3, 4);
Assert.False(v == v - 0);
Assert.False(v == v.Subtract(0));
Assert.False(-v == v.SubtractFrom(0));
Assert.True(v.Equivalent(v - 0));
Assert.True(v.Equivalent(v.Subtract(0)));
Assert.True((-v).Equivalent(0 - v));
Assert.True((-v).Equivalent(v.SubtractFrom(0)));
Assert.True((v - v).Equivalent(Vector3d.Zero));
Assert.True((v.Subtract(v)).Equivalent(Vector3d.Zero));
Assert.True((v - .1).Equivalent(new Vector3d(1.9, 2.9, 3.9)));
Assert.True((v.Subtract(.1)).Equivalent(new Vector3d(1.9, 2.9, 3.9)));
Assert.True((.1 - v).Equivalent(new Vector3d(-1.9, -2.9, -3.9)));
Assert.True((v.SubtractFrom(.1)).Equivalent(new Vector3d(-1.9, -2.9, -3.9)));
}
