public void ShouldReturn0WhenMovingSouthFromFieldWith0YValue()
        {
            // arrange
            var initialField = new Field
            {
                Y = 0
            };

            var handler = new MoveSouthCommandHandler();

            // act
            var newField = handler.Move(initialField);

            // assert
            Assert.AreEqual(0, newField.Y);
        }
        public void ShouldReturnFieldYDecreasedByOneWhenMovingSouthFromFieldWithPositiveYValue()
        {
            // arrange
            var initialField = new Field
            {
                Y = 2
            };

            var handler = new MoveSouthCommandHandler();

            // act
            var newField = handler.Move(initialField);

            // assert
            Assert.AreEqual(1, newField.Y);
        }