test: add E2E test for session store delete and remove unused import

- Add test verifying onDelete is called when deleting a session
- Remove unused getFinalAssistantMessage import

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: SteveSandersonMS

nodejs/test/e2e/session_store.test.ts

@@ -5,7 +5,6 @@
 import { describe, expect, it, vi } from "vitest";
 import { approveAll, type SessionEvent, type SessionStoreConfig } from "../../src/index.js";
 import { createSdkTestContext } from "./harness/sdkTestContext.js";
-import { getFinalAssistantMessage } from "./harness/sdkTestHelper.js";
 
 /**
  * In-memory session event store for testing.
@@ -174,4 +173,33 @@ describe("Session Store", async () => {
             }),
         ).rejects.toThrow(/Cannot change storage backend/);
     });
+
+    it("should call onDelete when deleting a session", async () => {
+        const store = new InMemorySessionStore();
+        const storeConfig = store.toConfig("memory://test-delete");
+
+        const session = await client.createSession({
+            onPermissionRequest: approveAll,
+            sessionStore: storeConfig,
+        });
+        const sessionId = session.sessionId;
+
+        // Send a message to create some events
+        await session.sendAndWait({ prompt: "What is 7 + 7?" });
+
+        // Wait for events to flush
+        await vi.waitFor(
+            () => expect(store.hasSession(sessionId)).toBe(true),
+            { timeout: 10_000, interval: 200 },
+        );
+
+        expect(store.calls.delete).toBe(0);
+
+        // Delete the session
+        await client.deleteSession(sessionId);
+
+        // Verify onDelete was called and the session was removed from our store
+        expect(store.calls.delete).toBeGreaterThan(0);
+        expect(store.hasSession(sessionId)).toBe(false);
+    });
 });

test/snapshots/session_store/should_call_ondelete_when_deleting_a_session.yaml

@@ -0,0 +1,10 @@
+models:
+  - claude-sonnet-4.5
+conversations:
+  - messages:
+      - role: system
+        content: ${system}
+      - role: user
+        content: What is 7 + 7?
+      - role: assistant
+        content: 7 + 7 = 14