public void CountTreesTest(int right, int down, int expectedTreeCount)
        {
            // Arrange
            var screenBuffer = new ScreenBuffer(_input);
            var routePlanner = new RoutePlanner(screenBuffer);

            // Act
            var treeCount = routePlanner.CountTrees(new SlopeModel {
                Right = right, Down = down
            });

            // Assert
            Assert.That(treeCount, Is.EqualTo(expectedTreeCount));
        }