Add failing test case where NodeCollection would panic

This issue arises when a graph involves nodes connecting to audio
params.  E.g. constant src -> playback rate -> buffer src.

The playbackrate param is dropped alongside the buffer src if it has
ended, but this leaves an edge from the constant src in place.

To solve this we probably need a bit more refactoring, stay tuned

Author: orottier

src/render/graph.rs

@@ -829,6 +829,69 @@ mod tests {
         assert!(node_id_consumer.pop().is_none());
     }
 
+    #[test]
+    fn test_audio_param_with_signal_lifecycle() {
+        let (node_id_producer, mut node_id_consumer) = llq::Queue::new().split();
+        let mut graph = Graph::new(node_id_producer);
+
+        let node = Box::new(TestNode { tail_time: false });
+
+        // Destination Node is always node id 0, and should never drop
+        add_node(&mut graph, 0, node.clone());
+
+        // AudioListener Node is always node id 1, and should never drop
+        add_node(&mut graph, 1, node.clone());
+
+        // Add a regular node at id 3, it has tail time false so after rendering it should be
+        // dropped and the AudioNodeId(3) should be reclaimed
+        add_node(&mut graph, 2, node.clone());
+        // Mark the node as 'detached from the control thread', so it is allowed to drop
+        graph
+            .nodes
+            .get_unchecked_mut(AudioNodeId(2))
+            .control_handle_dropped = true;
+
+        // Connect the regular node to the AudioDestinationNode
+        add_edge(&mut graph, 2, 0);
+
+        // Add an AudioParam at id 4, it should be dropped alongside the regular node
+        let param = Box::new(TestNode { tail_time: true }); // audio params have tail time true
+        add_node(&mut graph, 3, param);
+        // Mark the node as 'detached from the control thread', so it is allowed to drop
+        graph
+            .nodes
+            .get_unchecked_mut(AudioNodeId(3))
+            .control_handle_dropped = true;
+
+        // Connect the audioparam to the regular node
+        add_audioparam(&mut graph, 3, 2);
+
+        // Add a source node to feed into the AudioParam
+        let signal = Box::new(TestNode { tail_time: true });
+        add_node(&mut graph, 4, signal);
+        add_edge(&mut graph, 4, 3);
+
+        // Render a single quantum
+        let scope = AudioWorkletGlobalScope {
+            current_frame: 0,
+            current_time: 0.,
+            sample_rate: 48000.,
+            node_id: std::cell::Cell::new(AudioNodeId(0)),
+            event_sender: None,
+        };
+        graph.render(&scope);
+
+        // First the regular node should be dropped, then the audioparam
+        assert_eq!(node_id_consumer.pop().unwrap().0, 2);
+        assert_eq!(node_id_consumer.pop().unwrap().0, 3);
+
+        // No other dropped nodes
+        assert!(node_id_consumer.pop().is_none());
+
+        // Render again
+        graph.render(&scope);
+    }
+
     #[test]
     fn test_release_orphaned_source_nodes() {
         let (node_id_producer, mut node_id_consumer) = llq::Queue::new().split();