Add unit test for basic Gst.Element subclasses

This implements a simple source and sink and sends 10 buffers from one
to another.

tests/ElementTest.cs

@@ -9,6 +9,7 @@
 
 using System;
 using NUnit.Framework;
+using GLib;
 using Gst;
 
 [TestFixture]
@@ -74,4 +75,147 @@ public class ElementTest
 		source.Unlink(sink);
 		Assert.IsFalse(source.GetStaticPad("src").IsLinked);
 	}
+	
+	public class TestSubclassesApp {
+		static MainLoop loop;
+
+		public class MySrc : Gst.Element {
+			public MySrc () : base () {
+				Init ();
+			}
+			
+			public MySrc (IntPtr raw) : base (raw) {
+				Init ();
+			}
+			
+			private Pad src;
+			private uint nbuffers = 0;
+			
+			private void Init () {
+				src = new Pad (templ, "src");
+				AddPad (src);
+			}
+			
+			static Caps caps = Caps.FromString ("my/dummy-data");
+			
+			private void loop () {
+				Gst.Buffer buf = new Gst.Buffer ();
+				buf.Caps = caps;
+				Gst.FlowReturn ret = src.Push (buf);
+				nbuffers++;
+				
+				Assert.AreEqual (ret, Gst.FlowReturn.Ok);
+				if (ret != Gst.FlowReturn.Ok) {
+					src.StopTask ();
+					this.PostMessage (Message.NewError (this, CoreError.Failed, "Oh no"));
+				}
+
+				if (nbuffers == 10) {
+					Assert.IsTrue (src.PushEvent (Gst.Event.NewEos ()));
+					src.PauseTask ();
+				}
+			}
+			
+			protected override StateChangeReturn OnChangeState (StateChange transition) {
+				if (transition == StateChange.ReadyToPaused)
+					src.StartTask (loop);
+				else if (transition == StateChange.PausedToReady)
+					src.StopTask ();
+			
+				return StateChangeReturn.Success;
+			}
+			
+			static PadTemplate templ = new PadTemplate ("src", Gst.PadDirection.Src, Gst.PadPresence.Always, Caps.FromString ("my/dummy-data"));
+			
+			public static bool Register () {
+				SetDetails ( (GType) typeof (MySrc), "long", "klass", "desc", "author");
+				AddPadTemplate ( (GType) typeof (MySrc), templ);
+				return ElementFactory.Register (null, "mysrc", (uint) Gst.Rank.None, (GType) typeof (MySrc));
+			}
+		}
+		
+		public class MySink : Gst.Element {
+			public MySink () : base () {
+				Init ();
+			}
+			
+			public MySink (IntPtr raw) : base (raw) {
+				Init ();
+			}
+			
+			Gst.FlowReturn on_chain (Gst.Pad pad, Gst.Buffer buffer) {
+				Assert.IsNotNull (buffer);
+				return Gst.FlowReturn.Ok;
+			}
+
+			bool on_event (Gst.Pad pad, Gst.Event evnt) {
+				if (evnt.Type == Gst.EventType.Eos) {
+					this.PostMessage (Message.NewEos (this));
+				}
+
+				return true;
+			}
+			
+			private void Init () {
+				Pad pad = new Pad (templ, "sink");
+				pad.ChainFunction = on_chain;
+				pad.EventFunction = on_event;
+				AddPad (pad);
+			}
+			
+			static PadTemplate templ = new PadTemplate ("sink", Gst.PadDirection.Sink, Gst.PadPresence.Always, Caps.FromString ("my/dummy-data"));
+			
+			public static bool Register () {
+				SetDetails ( (GType) typeof (MySink), "long", "klass", "desc", "author");
+				AddPadTemplate ( (GType) typeof (MySink), templ);
+				
+				return ElementFactory.Register (null, "mysink", (uint) Gst.Rank.None, (GType) typeof (MySink));
+			}
+		}
+
+		private static bool BusCb (Bus bus, Message message) {
+			switch (message.Type) {
+				case MessageType.Error:
+					Enum err;
+					string msg;
+					
+					message.ParseError (out err, out msg);
+					Assert.Fail (String.Format ("Error message: {0}", msg));
+					loop.Quit ();
+					break;
+				case MessageType.Eos:
+					loop.Quit ();
+					break;
+			}
+			return true;
+		}
+		
+		public static void Run () {
+		
+			MySrc.Register ();
+			MySink.Register ();
+			
+			MySrc mysrc = Gst.ElementFactory.Make ("mysrc") as MySrc;
+			MySink mysink = Gst.ElementFactory.Make ("mysink") as MySink;
+			
+			Gst.Pipeline pipeline = new Pipeline ("pipeline");
+			pipeline.Add (mysrc, mysink);
+			Assert.IsTrue (mysrc.Link (mysink));
+			
+			loop = new MainLoop ();
+			
+			pipeline.Bus.AddWatch (new BusFunc (BusCb));
+			pipeline.SetState (Gst.State.Playing);
+			
+			loop.Run ();
+
+			pipeline.SetState (Gst.State.Null);
+		}
+	}
+
+	[Test]
+	public void TestSubclasses ()
+	{
+		TestSubclassesApp.Run ();			
+	}
 }