Frame timing

tests/RenderOutputQueueTests.cpp

@@ -94,6 +94,29 @@ void TestOverflowReleasesDroppedFrame()
 	Expect(gReleasedFrames == 1, "pop transfers ownership without releasing");
 }
 
+void TestDropOldestFrameReleasesFrame()
+{
+	gReleasedFrames = 0;
+	VideoPlayoutPolicy policy;
+	policy.maxReadyFrames = 2;
+	RenderOutputQueue queue(policy);
+
+	queue.Push(MakeOwnedFrame(1));
+	queue.Push(MakeOwnedFrame(2));
+
+	Expect(queue.DropOldestFrame(), "oldest ready frame can be explicitly dropped");
+	Expect(gReleasedFrames == 1, "explicit drop releases oldest frame");
+
+	RenderOutputQueueMetrics metrics = queue.GetMetrics();
+	Expect(metrics.depth == 1, "explicit drop reduces queue depth");
+	Expect(metrics.droppedCount == 1, "explicit drop increments dropped count");
+
+	RenderOutputFrame frame;
+	Expect(queue.TryPop(frame), "newest frame remains after explicit drop");
+	Expect(frame.frameIndex == 2, "explicit drop keeps newest frame");
+	Expect(!queue.DropOldestFrame(), "empty queue cannot drop a frame");
+}
+
 void TestUnderrunIsCounted()
 {
 	RenderOutputQueue queue;
@@ -169,6 +192,7 @@ int main()
 	TestQueuePreservesOrdering();
 	TestBoundedQueueDropsOldestFrame();
 	TestOverflowReleasesDroppedFrame();
+	TestDropOldestFrameReleasesFrame();
 	TestUnderrunIsCounted();
 	TestConfigureShrinksDepthToNewCapacity();
 	TestConfigureReleasesTrimmedFrames();