public void QueueViaStacksTest()
{
var myQueue = new QueueViaStacks <int>();
// not possible to dequeue from an empty queue
Assert.Equal(0, myQueue.Length);
Assert.Throws <System.InvalidOperationException>(() => myQueue.Dequeue());
// items are added by enqueue
for (int i = 0; i < 3; i++)
{
myQueue.Enqueue(i);
}
Assert.Equal(3, myQueue.Length);
// valid values are dequeued
Assert.Equal(0, myQueue.Dequeue());
Assert.Equal(1, myQueue.Dequeue());
Assert.Equal(1, myQueue.Length);
// enqueing new value doesn't break the dequeue
myQueue.Enqueue(3);
Assert.Equal(2, myQueue.Dequeue());
// peek returns value without removing it from the queue
Assert.Equal(1, myQueue.Length);
Assert.Equal(3, myQueue.Peek());
Assert.Equal(1, myQueue.Length);
// clear removes all values from the queue
myQueue.Clear();
Assert.Equal(0, myQueue.Length);
}
private static void CollectionsEqual(int[] expected, QueueViaStacks <int> actual)
{
Assert.Equal(expected.Length, actual.Count());
foreach (var item in expected)
{
Assert.Equal(item, actual.Remove());
}
}
public void QueueViaStacks_Pop_WhenEmpty_ThrowsEmptyQueueException()
{
// Arrange
var queueViaStacks = new QueueViaStacks <int>();
Action action = () => { queueViaStacks.Pop(); };
// Act && Assert
action.Should().Throw <EmptyQueueException>().WithMessage("Queue is Empty");
}
private static QueueViaStacks <int> CreateQueueViaStacksFromArray(int[] input)
{
QueueViaStacks <int> queue = new QueueViaStacks <int>();
foreach (var item in input)
{
queue.Add(item);
}
return(queue);
}
public void ReturnValuesInFIFOOrderingAfterModifications()
{
QueueViaStacks <int> queue = CreateQueueViaStacksFromArray(new [] { 9, 6, 1, 2 });
Assert.Equal(9, queue.Peek());
Assert.Equal(9, queue.Remove());
Assert.Equal(6, queue.Remove());
queue.Add(3);
queue.Add(4);
CollectionsEqual(new [] { 1, 2, 3, 4 }, queue);
}
public void QueueViaStacks_IsEmpty_WhenEmpty_ReturnsTrue()
{
// Arrange
var queueViaStacks = new QueueViaStacks <int>();
// Act
var isEmpty = queueViaStacks.IsEmpty();
// Assert
isEmpty.Should().BeTrue();
}
public void QueueViaStacks_Peek_WhenNotEmpty_ReturnsOldestElements()
{
// Arrange
var queueViaStacks = new QueueViaStacks <int>();
queueViaStacks.Push(1);
queueViaStacks.Push(2);
queueViaStacks.Push(3);
queueViaStacks.Push(4);
queueViaStacks.Push(5);
// Act&Assert
queueViaStacks.Peek().Should().Be(1);
queueViaStacks.Push(6);
queueViaStacks.Pop();
queueViaStacks.Peek().Should().Be(2);
}
public void ReturnValuesInFIFOOrdering(int[] input)
{
QueueViaStacks <int> queue = CreateQueueViaStacksFromArray(input);
CollectionsEqual(input, queue);
}
