test: tighten media tool factory assertions

src/agents/tools/image-generate-tool.test.ts

@@ -113,7 +113,7 @@ function stubImageGenerationProviders() {
 }
 
 function requireImageGenerateTool(tool: ReturnType<typeof createImageGenerateTool>) {
-  expect(tool).not.toBeNull();
+  expect(typeof tool?.execute).toBe("function");
   if (!tool) {
     throw new Error("expected image_generate tool");
   }

src/agents/tools/music-generate-tool.test.ts

@@ -207,7 +207,7 @@ describe("createMusicGenerateTool", () => {
         },
       }),
     });
-    expect(tool).not.toBeNull();
+    expect(typeof tool?.execute).toBe("function");
     if (!tool) {
       throw new Error("expected music_generate tool");
     }
@@ -277,7 +277,7 @@ describe("createMusicGenerateTool", () => {
         },
       }),
     });
-    expect(tool).not.toBeNull();
+    expect(typeof tool?.execute).toBe("function");
     if (!tool) {
       throw new Error("expected music_generate tool");
     }

src/agents/tools/pdf-tool.test.ts

@@ -49,7 +49,7 @@ function requirePdfTool(
     ? R
     : never,
 ) {
-  expect(tool).not.toBeNull();
+  expect(typeof tool?.execute).toBe("function");
   if (!tool) {
     throw new Error("expected pdf tool");
   }

src/agents/tools/video-generate-tool.test.ts

@@ -309,7 +309,7 @@ describe("createVideoGenerateTool", () => {
         },
       }),
     });
-    expect(tool).not.toBeNull();
+    expect(typeof tool?.execute).toBe("function");
     if (!tool) {
       throw new Error("expected video_generate tool");
     }
@@ -589,7 +589,7 @@ describe("createVideoGenerateTool", () => {
         },
       }),
     });
-    expect(tool).not.toBeNull();
+    expect(typeof tool?.execute).toBe("function");
     if (!tool) {
       throw new Error("expected video_generate tool");
     }