/// <summary>
/// Adds a wheel to the vehicle.
/// </summary>
/// <param name="wheel">WheelTest to add.</param>
public void AddWheel(Wheel wheel)
{
if (wheel.vehicle == null)
{
Wheels.Add(wheel);
wheel.OnAddedToVehicle(this);
}
else
{
throw new InvalidOperationException("Can't add a wheel to a vehicle if it already belongs to a vehicle.");
}
}