test: guard channel loader jiti mock call

src/channels/plugins/module-loader.test.ts

@@ -26,6 +26,16 @@ function createTempDir(): string {
   return tempDir;
 }
 
+function requireCreateJitiCall(
+  createJiti: ReturnType<typeof vi.fn>,
+): [string, { tryNative?: boolean }] {
+  const call = createJiti.mock.calls.at(0);
+  if (!call) {
+    throw new Error("expected createJiti call");
+  }
+  return call as [string, { tryNative?: boolean }];
+}
+
 describe("channel plugin module loader helpers", () => {
   it("resolves extensionless plugin module specifiers to the first existing extension", () => {
     const rootDir = createTempDir();
@@ -102,9 +112,9 @@ describe("channel plugin module loader helpers", () => {
         target: fs.realpathSync.native(modulePath),
       });
       expect(createJiti).toHaveBeenCalledOnce();
-      const [loaderFilename, loaderOptions] = createJiti.mock.calls[0] ?? [];
+      const [loaderFilename, loaderOptions] = requireCreateJitiCall(createJiti);
       expect(loaderFilename).toContain("module-loader.ts");
-      expect(loaderOptions?.tryNative).toBe(false);
+      expect(loaderOptions.tryNative).toBe(false);
       expect(loadWithJiti).toHaveBeenCalledWith(fs.realpathSync.native(modulePath));
     } finally {
       for (const [extension, hook] of sourceHooks) {