private void TestCtor(Cell c, Direction dir)
{
MovementNode m = new MovementNode(c, dir);
Assert.AreEqual(c, m.Cell);
Assert.AreEqual(dir, m.MovementDirection);
}
private void LengthChangeTest(Grid g, Cell c, int length, Direction dir)
{
Snake s = new Snake(g, c, length, dir);
MovementNode oldHead = s.Head;
MovementNode oldEnd = s.End;
s.Length = s.Length;
Assert.AreEqual(oldHead, s.Head, "Settin Snake.Length to the same value as it currently has should change nothing (head check).");
Assert.AreEqual(oldEnd, s.End, "Settin Snake.Length to the same value as it currently has should change nothing (end check).");
int oldLength = s.Length;
int newLength = oldLength + 5;
s.Length = newLength;
Assert.AreEqual(newLength, s.Length, "Setting the Snake.Length property should update the Snake.Length getter (increment).");
Assert.AreEqual(oldHead, s.Head, "Setting the Snake.Length property should not change the snake's head (increment).");
Assert.AreNotEqual(oldEnd, s.End, "Setting the Snake.Length property to any value except the value it already had should change Snake.End (increment).");
List <MovementNode> nodes = new List <MovementNode>(s.Tail);
Assert.AreEqual(newLength, nodes.Count, "The number of MovementNodes in Snake.Tail must match one-to-one with the snake's length at all times (length increase check).");
int offset = 1;
int increment = oldEnd.MovementDirection.Invert().Sign();
bool xAxis = dir.GetAxis() == Axis2D.X;
Cell check;
for (int i = oldLength; i < newLength; i++, offset++)
{
Assert.AreEqual(oldEnd.MovementDirection, nodes[i].MovementDirection, "Increasing Snake.Length should create new MovementNodes in the same direction as Snake.End.MovementDirection.");
check = xAxis ? g[oldEnd.Cell.X + offset * increment, oldEnd.Cell.Y] : g[oldEnd.Cell.X, oldEnd.Cell.Y + offset * increment];
Assert.AreEqual(check, nodes[i].Cell, "Increasing Snake.Length should create new MovementNodes with a position off by one of the previous MovementNode, in accordance with MovementDirection.");
}
oldEnd = s.End;
newLength -= 2;
s.Length = newLength;
Assert.AreEqual(newLength, s.Length, "Setting the Snake.Length property should update the Snake.Length getter (decrement).");
Assert.AreEqual(oldHead, s.Head, "Setting the Snake.Length property should not change the snake's head (decrement).");
Assert.AreNotEqual(oldEnd, s.End, "Setting the Snake.Length property to any value except the value it already had should change Snake.End (decrement).");
List <MovementNode> newNodes = new List <MovementNode>(s.Tail);
Assert.AreEqual(newLength, newNodes.Count, "The number of MovementNodes in Snake.Tail must match one-to-one with the snake's length at all times (length decrease check).");
Assert.IsFalse(newNodes.Contains(nodes[nodes.Count - 1]), "Decreasing the snake's length by n should remove n nodes from the end of the tail (count - 1).");
Assert.IsFalse(newNodes.Contains(nodes[nodes.Count - 2]), "Decreasing the snake's length by n should remove n nodes from the end of the tail (count - 2).");
}