public void IndicatesUndoPossible()
{
var manager = new UndoManager(5);
manager.SaveState(new ProjectState(""));
Assert.False(manager.CanUndo());
manager.SaveState(new ProjectState(""));
Assert.True(manager.CanUndo());
manager.Undo();
Assert.False(manager.CanUndo());
}
public void LimitsHistoryCount()
{
const uint size = 5u;
var manager = new UndoManager(size);
for (int i = 0; i < size * 2; i++)
manager.SaveState(new ProjectState(""));
uint counter = 0;
while (manager.Undo() != null)
counter++;
Assert.Equal(size, counter);
}
public void Redoes()
{
var steps = new[] { "b", "c" }.Select(s => new ProjectState(s)).ToList();
var manager = new UndoManager(5);
manager.SaveState(new ProjectState("a"));
foreach (ProjectState step in steps)
manager.SaveState(step);
for (int i = 0; i < 2; i++)
manager.Undo();
var result = new List<ProjectState>();
for (int i = 0; i < 2; i++)
result.Add(manager.Redo());
Assert.Equal(steps, result);
}
public void ReturnsNullWhenOutOfItems()
{
var manager = new UndoManager(3);
manager.SaveState(new ProjectState(""));
manager.Undo();
Assert.Null(manager.Undo());
manager.Redo();
Assert.Null(manager.Redo());
}
public void WorksWithZeroCapacity()
{
var manager = new UndoManager(0);
manager.SaveState(new ProjectState(""));
Assert.Null(manager.Undo());
Assert.Null(manager.Redo());
}