Harden movie playback lifecycle and diagnostics

engine/Age.Engine.Tests/GfxDiagnosticSnapshotTests.cs

@@ -0,0 +1,24 @@
+using Age.Engine.Model;
+
+public class GfxDiagnosticSnapshotTests
+{
+    [Fact]
+    public void SnapshotIdentifiesOnlyChannelsThatCanBlockPresentationWait()
+    {
+        var gfx = new GfxState();
+        gfx.BindDraw(0x100, 7, 0, 0, 32, 32, 0, 0);
+        gfx.SetTranslationChannel(0x100, 25, 300, (20, 30, 0));
+        gfx.BindDraw(0x200, 8, 0, 0, 32, 32, 0, 0);
+        gfx.SetScaleChannel(0x200, 0, 500, (200, 200, 100));
+        gfx.SetOneShotAnimationControl(0x200, 1);
+
+        GfxDiagnosticSnapshot snapshot = gfx.CaptureDiagnosticSnapshot(1000);
+
+        Assert.True(snapshot.HasActiveTimedPresentation);
+        var blocking = Assert.Single(snapshot.BlockingObjects);
+        Assert.Equal(0x100, blocking.Handle);
+        Assert.True(blocking.TranslationEnabled);
+        Assert.Equal(25, blocking.TranslationDelayMs);
+        Assert.Equal(300, blocking.TranslationDurationMs);
+    }
+}