LTE Mars Rover - Turning Left

Rover.cs

public void TurnLeft()
{
  if (Orientation == Direction.North) {
    Orientation = Direction.West;
  }
}

public void TurnLeft()
{
  if (Orientation == Direction.North) {
    Orientation = Direction.West;
  }
  else if (Orientation == Direction.West) {
    Orientation = Direction.South;
  }
}

public void TurnLeft()
{
  if (Orientation == Direction.North) {
    Orientation = Direction.West;
  }
  else if (Orientation == Direction.West) {
    Orientation = Direction.South;
  }
  else if (Orientation == Direction.South) {
    Orientation = Direction.East;
  }
}

public void TurnLeft()
{
  if (Orientation == Direction.North) {
    Orientation = Direction.West;
  }
  else if (Orientation == Direction.West) {
    Orientation = Direction.South;
  }
  else if (Orientation == Direction.South) {
    Orientation = Direction.East;
  }
  else if (Orientation == Direction.East) {
    Orientation = Direction.North;
  }
}

WhenTurningLeft.cs

[TestFixture]
public class WhenTurningLeft
{
  [Test]
  public void AndFacingNorthThenTheRoverFacesWest()
  {
    var rover = new Rover {Orientation=Direction.North};
    var initialLocation = rover.Location;
    
    rover.TurnLeft();
    
    Assert.AreEqual(initialLocation, rover.Location);
    Assert.AreEqual(Direction.West, rover.Orientation);
  }
  
  [Test]
  public void AndFacingWestThenTheRoverFacesSouth()
  {
    var rover = new Rover {Orientation=Direction.West};
    var initialLocation = rover.Location;
    
    rover.TurnLeft();
    
    Assert.AreEqual(initialLocation, rover.Location);
    Assert.AreEqual(Direction.South, rover.Orientation);
  }
  
  [Test]
  public void AndFacingSouthThenTheRoverFacesEast()
  {
    var rover = new Rover {Orientation=Direction.South};
    var initialLocation = rover.Location;
    
    rover.TurnLeft();
    
    Assert.AreEqual(initialLocation, rover.Location);
    Assert.AreEqual(Direction.East, rover.Orientation);
  }
  
  [Test]
  public void AndFacingEastThenTheRoverFacesNorth()
  {
    var rover = new Rover {Orientation=Direction.East};
    var initialLocation = rover.Location;
    
    rover.TurnLeft();
    
    Assert.AreEqual(initialLocation, rover.Location);
    Assert.AreEqual(Direction.North, rover.Orientation);
  }
}

WhenTurningLeftFinal.cs

[TestFixture]
public class WhenTurningLeft
{  
  [Test]
  [TestCase(Direction.North, Direction.West, TestName = "AndFacingNorthThenTheRoverFacesWest")]
  [TestCase(Direction.West, Direction.South, TestName = "AndFacingWestThenTheRoverFacesSouth")]
  [TestCase(Direction.South, Direction.East, TestName = "AndFacingSouthThenTheRoverFacesEast")]
  [TestCase(Direction.East, Direction.North, TestName = "AndFacingEastThenTheRoverFacesNorth")]
  public void RoverTurningLeft(Direction start, Direction expected)
  {
    var rover = new Rover { Orientation = start };
    var initialLocation = rover.Location;

    rover.TurnLeft();

    Assert.AreEqual(expected, rover.Orientation);
    Assert.AreEqual(initialLocation, rover.Location);
  }
}

WhenTurningLeftTestCase.cs

[TestFixture]
public class WhenTurningLeft
{
  [Test]
  [TestCase(Direction.East, Direction.North, TestName = "AndFacingEastThenTheRoverFacesNorth")]
  public void RoverTurningLeft(Direction start, Direction expected)
  {
    var rover = new Rover { Orientation = start };
    var initialLocation = rover.Location;

    rover.TurnLeft();

    Assert.AreEqual(expected, rover.Orientation);
    Assert.AreEqual(initialLocation, rover.Location);
  }
  
  [Test]
  [TestCase(Direction.North, Direction.West, TestName = "AndFacingNorthThenTheRoverFacesWest")]
  [TestCase(Direction.West, Direction.South, TestName = "AndFacingWestThenTheRoverFacesSouth")]
  [TestCase(Direction.South, Direction.East, TestName = "AndFacingSouthThenTheRoverFacesEast")]
  [TestCase(Direction.East, Direction.North, TestName = "AndFacingEastThenTheRoverFacesNorth")]
  public void RoverTurningLeft(Direction start, Direction expected)
  {
    var rover = new Rover { Orientation = start };
    var initialLocation = rover.Location;

    rover.TurnLeft();

    Assert.AreEqual(expected, rover.Orientation);
    Assert.AreEqual(initialLocation, rover.Location);
  }
}