using System;
using System.Collections.Generic;

#if UNITTEST

using NUnit.Framework;
using NMock2;

namespace Nuclex.Support.Collections {

  /// <summary>Unit Test for the observable collection class</summary>
  [TestFixture]
  public class ObservableCollectionTest {

    /// <summary>Interface used to test the observable collection.</summary>
    public interface IObservableCollectionSubscriber {

      /// <summary>Called when the collection is about to clear its contents</summary>
      /// <param name="sender">Collection that is clearing its contents</param>
      /// <param name="e">Not used</param>
      void Clearing(object sender, EventArgs e);

      /// <summary>Called when an item is added to the collection</summary>
      /// <param name="sender">Collection to which an item is being added</param>
      /// <param name="e">Contains the item that is being added</param>
      void ItemAdded(object sender, ObservableCollection<int>.ItemEventArgs e);

      /// <summary>Called when an item is removed from the collection</summary>
      /// <param name="sender">Collection from which an item is being removed</param>
      /// <param name="e">Contains the item that is being removed</param>
      void ItemRemoved(object sender, ObservableCollection<int>.ItemEventArgs e);

    }

    /// <summary>Initialization routine executed before each test is run</summary>
    [SetUp]
    public void Setup() {
      this.mockery = new Mockery();

      this.mockedSubscriber = this.mockery.NewMock<IObservableCollectionSubscriber>();

      this.observedCollection = new ObservableCollection<int>();
      this.observedCollection.Clearing += new EventHandler(this.mockedSubscriber.Clearing);
      this.observedCollection.ItemAdded +=
        new EventHandler<ObservableCollection<int>.ItemEventArgs>(
          this.mockedSubscriber.ItemAdded
        );
      this.observedCollection.ItemRemoved +=
        new EventHandler<ObservableCollection<int>.ItemEventArgs>(
          this.mockedSubscriber.ItemRemoved
        );

      this.mockery.VerifyAllExpectationsHaveBeenMet();
    }

    /// <summary>Tests whether the Clearing event is fired</summary>
    [Test]
    public void TestClearingEvent() {
      Expect.Once.On(this.mockedSubscriber).
        Method("Clearing");

      this.observedCollection.Clear();

      this.mockery.VerifyAllExpectationsHaveBeenMet();
    }

    /// <summary>Tests whether the ItemAdded event is fired</summary>
    [Test]
    public void TestItemAddedEvent() {
      Expect.Once.On(this.mockedSubscriber).
        Method("ItemAdded").
        WithAnyArguments();

      this.observedCollection.Add(123);

      this.mockery.VerifyAllExpectationsHaveBeenMet();
    }

    /// <summary>Tests whether the ItemRemoved event is fired</summary>
    [Test]
    public void TestItemRemovedEvent() {
      Expect.Once.On(this.mockedSubscriber).
        Method("ItemAdded").
        WithAnyArguments();

      Expect.Once.On(this.mockedSubscriber).
        Method("ItemRemoved").
        WithAnyArguments();

      this.observedCollection.Add(123);
      this.observedCollection.Remove(123);

      this.mockery.VerifyAllExpectationsHaveBeenMet();
    }

    /// <summary>Mock object factory</summary>
    private Mockery mockery;
    /// <summary>The mocked observable collection subscriber</summary>
    private IObservableCollectionSubscriber mockedSubscriber;
    /// <summary>An observable collection to which a mock will be subscribed</summary>
    private ObservableCollection<int> observedCollection;

  }

} // namespace Nuclex.Support.Collections

#endif // UNITTEST