public void ShouldReturnDirection(Direction direction) { var randomiser = new Mock <IRandom>(); var listOfOptions = new List <Direction> { Direction.North, Direction.South, Direction.East, Direction.West }; randomiser.Setup(x => x.SelectRandomDirection(listOfOptions)) .Returns(direction); var player = new AIPlayer(randomiser.Object); var result = player.DecideNextMove(listOfOptions); Assert.Equal(direction, result); }