diff --git a/packages/core/tests/indices/SummaryIndex.test.ts b/packages/core/tests/indices/SummaryIndex.test.ts
index 846a61e9db4a1e1ce3a62ec062cfb4bcf07defd9..89277f6e837646544ae8498e640450d8eb9fe24d 100644
--- a/packages/core/tests/indices/SummaryIndex.test.ts
+++ b/packages/core/tests/indices/SummaryIndex.test.ts
@@ -7,7 +7,14 @@ import {
   type StorageContext,
 } from "llamaindex";
 import { rmSync } from "node:fs";
-import { afterAll, beforeAll, describe, expect, it } from "vitest";
+import { afterAll, beforeAll, describe, expect, it, vi } from "vitest";
+
+vi.mock("llamaindex/llm/open_ai", () => {
+  return {
+    getOpenAISession: vi.fn().mockImplementation(() => null),
+  };
+});
+
 import { mockServiceContext } from "../utility/mockServiceContext.js";
 
 describe("SummaryIndex", () => {
diff --git a/packages/core/tests/indices/VectorStoreIndex.test.ts b/packages/core/tests/indices/VectorStoreIndex.test.ts
index 4e9f3694a563fb2a0a389788f9b2629e2bb2ed7b..b79af7311960c8358ea6fb6db6a4570b9c35070e 100644
--- a/packages/core/tests/indices/VectorStoreIndex.test.ts
+++ b/packages/core/tests/indices/VectorStoreIndex.test.ts
@@ -4,9 +4,15 @@ import {
   VectorStoreIndex,
   storageContextFromDefaults,
 } from "llamaindex";
-import { beforeAll, describe, expect, test } from "vitest";
+import { beforeAll, describe, expect, test, vi } from "vitest";
 import { mockServiceContext } from "../utility/mockServiceContext.js";
 
+vi.mock("llamaindex/llm/open_ai", () => {
+  return {
+    getOpenAISession: vi.fn().mockImplementation(() => null),
+  };
+});
+
 describe.sequential("VectorStoreIndex", () => {
   let serviceContext: ServiceContext;
   let storageContext: StorageContext;
diff --git a/packages/core/tests/objects/ObjectIndex.test.ts b/packages/core/tests/objects/ObjectIndex.test.ts
index 08203f50fd98d504b33c1a4a49b58d1dca7da963..356657919e8ba3219e80ddb89df23e659652df8d 100644
--- a/packages/core/tests/objects/ObjectIndex.test.ts
+++ b/packages/core/tests/objects/ObjectIndex.test.ts
@@ -5,7 +5,14 @@ import {
   SimpleToolNodeMapping,
   VectorStoreIndex,
 } from "llamaindex";
-import { beforeAll, describe, expect, test } from "vitest";
+import { beforeAll, describe, expect, test, vi } from "vitest";
+
+vi.mock("llamaindex/llm/open_ai", () => {
+  return {
+    getOpenAISession: vi.fn().mockImplementation(() => null),
+  };
+});
+
 import { mockServiceContext } from "../utility/mockServiceContext.js";
 
 describe("ObjectIndex", () => {
diff --git a/packages/core/tests/utility/mockServiceContext.ts b/packages/core/tests/utility/mockServiceContext.ts
index 03b0893b82a50216f40f280516a4a213ae8f8134..f6843069c472637272449be8182d04f3ad844f3d 100644
--- a/packages/core/tests/utility/mockServiceContext.ts
+++ b/packages/core/tests/utility/mockServiceContext.ts
@@ -9,15 +9,6 @@ import {
   mockLlmGeneration,
 } from "../utility/mockOpenAI.js";
 
-import { vi } from "vitest";
-
-// Mock the OpenAI getOpenAISession function during testing
-vi.mock("llamaindex/llm/open_ai", () => {
-  return {
-    getOpenAISession: vi.fn().mockImplementation(() => null),
-  };
-});
-
 export function mockServiceContext() {
   const embeddingModel = new OpenAIEmbedding();
   const llm = new OpenAI();