test(companion): add platform event subscription lifecycle integration

src/companion/platformClients.integration.test.ts

@@ -108,6 +108,29 @@ function createRuntime(): CompanionRuntimeClient {
 }
 
 describe('platform clients integration', () => {
+  it('platform event subscription helpers track subscription count lifecycle', async () => {
+    if (!LISTEN_ALLOWED) {
+      return;
+    }
+
+    const runtime = createRuntime();
+    const client = new MacOSCompanionClient({ runtime, nodeId: 'macos-events-e2e' });
+
+    expect(client.eventSubscriptionCount).toBe(0);
+    const unsubscribeA = client.subscribeEvents(() => undefined);
+    const unsubscribeB = client.subscribeEvent('agent.stream', () => undefined);
+    expect(client.eventSubscriptionCount).toBe(2);
+
+    unsubscribeA();
+    expect(client.eventSubscriptionCount).toBe(1);
+
+    client.clearEventSubscriptions();
+    expect(client.eventSubscriptionCount).toBe(0);
+
+    unsubscribeB();
+    expect(client.eventSubscriptionCount).toBe(0);
+  });
+
   it('platform connected reflects runtime connection lifecycle', async () => {
     if (!LISTEN_ALLOWED) {
       return;