fix: improve OpenAI mock implementation

Co-Authored-By: Han Xiao <[email protected]>

src/tools/__tests__/evaluator.test.ts

@@ -67,18 +67,18 @@ jest.mock('@ai-sdk/google', () => ({
 }));
 
 // Mock OpenAI API
-jest.mock('@ai-sdk/openai', () => ({
-  OpenAIChatLanguageModel: jest.fn().mockImplementation(() => ({
-    generateObject: jest.fn().mockImplementation(async () => ({
-      object: mockEvalResponse,
-      usage: { totalTokens: 0 }
-    })),
-    doGenerate: jest.fn().mockImplementation(async () => ({
-      object: mockEvalResponse,
-      usage: { totalTokens: 0 }
+jest.mock('@ai-sdk/openai', () => {
+  const mockResponse = {
+    object: mockEvalResponse,
+    usage: { totalTokens: 0 }
+  };
+  return {
+    OpenAIChatLanguageModel: jest.fn().mockImplementation(() => ({
+      generateObject: jest.fn().mockResolvedValue(mockResponse),
+      doGenerate: jest.fn().mockResolvedValue(mockResponse)
     }))
-  }))
-}));
+  };
+});
 
 jest.mock('../../utils/token-tracker');