public void IterateLiveCells_GivenGridWithTwoLiveCells_InvokesActionTwice()
{
// Arrange
var grid = new Grid();
grid.MarkLiveCellAt(Coords.Create(12, 13));
grid.MarkLiveCellAt(Coords.Create(13, 13));
var numInvocations = 0;
// Act
grid.IterateLiveCells((_, __) => numInvocations++);
// Assert
Assert.That(numInvocations, Is.EqualTo(2));
}
public void AnyDeadCellWithExactlyTwoLiveNeighboursStaysDead()
{
// Arrange
var grid = new Grid();
var cellCoords = Coords.Create(1, 1);
grid.MarkLiveCellAt(cellCoords.Below());
grid.MarkLiveCellAt(cellCoords.BelowLeft());
// Act
var actual = Rules.CurrentlyDeadCellWillBecomeALiveInTheNextGeneration(grid, cellCoords);
// Assert
Assert.That(actual, Is.False);
}
public void MarkLiveCellAt_CalledTwiceForTheSameCell_DoesNotAddCellTwice()
{
// Arrange
var grid = new Grid();
var coords = Coords.Create(12, 13);
grid.MarkLiveCellAt(coords);
grid.MarkLiveCellAt(coords);
var numInvocations = 0;
// Act
grid.IterateLiveCells((_, __) => numInvocations++);
// Assert
Assert.That(numInvocations, Is.EqualTo(1));
}
public void AnyLiveCellWithFourLiveNeighboursLivesOnToTheNextGeneration()
{
// Arrange
var grid = new Grid();
var cellCoords = Coords.Create(1, 1);
grid.MarkLiveCellAt(cellCoords);
grid.MarkLiveCellAt(cellCoords.Above());
grid.MarkLiveCellAt(cellCoords.Below());
grid.MarkLiveCellAt(cellCoords.BelowLeft());
grid.MarkLiveCellAt(cellCoords.BelowRight());
// Act
var actual = Rules.CurrentlyAliveCellWillStillBeALiveInTheNextGeneration(grid, cellCoords);
// Assert
Assert.That(actual, Is.False);
}
public void IsLiveCellAt_GivenCoordsWhereThereIsALiveCell_ReturnsTrue()
{
// Arrange
var grid = new Grid();
var coords = Coords.Create(12, 13);
grid.MarkLiveCellAt(coords);
// Act
var actual = grid.IsLiveCellAt(coords);
// Assert
Assert.That(actual, Is.True);
}
public void AnyLiveCellWithNoLiveNeighboursDies()
{
// Arrange
var grid = new Grid();
var cellCoords = Coords.Create(1, 1);
grid.MarkLiveCellAt(cellCoords);
// Act
var actual = Rules.CurrentlyAliveCellWillStillBeALiveInTheNextGeneration(grid, cellCoords);
// Assert
Assert.That(actual, Is.False);
}
public static Grid NextGeneration(Grid currentGrid)
{
var nextGrid = new Grid();
currentGrid.IterateLiveCells((coords, cellState) =>
{
if (CurrentlyAliveCellWillStillBeALiveInTheNextGeneration(currentGrid, coords))
{
nextGrid.MarkLiveCellAt(coords);
}
else
{
nextGrid.MarkWasPreviouslyAliveCellAt(coords);
}
foreach (var neighbour in coords.Neighbours())
{
if (!currentGrid.IsLiveCellAt(neighbour))
{
if (CurrentlyDeadCellWillBecomeALiveInTheNextGeneration(currentGrid, neighbour))
{
if (currentGrid.CellWasPreviouslyAliveAt(neighbour))
{
nextGrid.MarkZombieCellAt(neighbour);
}
else
{
nextGrid.MarkLiveCellAt(neighbour);
}
}
}
}
});
return nextGrid;
}
