public void SetUp()
{
_stopwatch = Substitute.For <IStopwatch>();
_stopwatch.ElapsedMilliseconds.ReturnsForAnyArgs(0);
_random = Substitute.For <IRandom>();
_animationSystem = new AnimationSystem(_stopwatch, _random);
_animationSystem.Initialise();
_testObject = CreateTestObject();
_animatedComponent = _testObject.Get <Animated>();
_animationSystem.AddEntity(_testObject);
}