chore: add a test that uses ping to check filter subscription (#1656)

* add a test that uses ping to check filter subscription

* remove comment

packages/tests/tests/filter/ping.node.spec.ts

@@ -59,4 +59,40 @@ describe("Waku Filter V2: Ping", function () {
     // Ping imediately after unsubscribe
     await validatePingError(subscription);
   });
+
+  it("Reopen subscription with peer with lost subscription", async function () {
+    const openSubscription = async (): Promise<void> => {
+      await subscription.subscribe([TestDecoder], messageCollector.callback);
+    };
+
+    const unsubscribe = async (): Promise<void> => {
+      await subscription.unsubscribe([TestContentTopic]);
+    };
+
+    const pingAndReinitiateSubscription = async (): Promise<void> => {
+      try {
+        await subscription.ping();
+      } catch (error) {
+        if (
+          error instanceof Error &&
+          error.message.includes("peer has no subscriptions")
+        ) {
+          await openSubscription();
+        } else {
+          throw error;
+        }
+      }
+    };
+
+    // open subscription & ping -> should pass
+    await openSubscription();
+    await pingAndReinitiateSubscription();
+
+    // unsubscribe & ping -> should fail and reinitiate subscription
+    await unsubscribe();
+    await pingAndReinitiateSubscription();
+
+    // ping -> should pass as subscription is reinitiated
+    await pingAndReinitiateSubscription();
+  });
 });