diff --git a/src/index.spec.ts b/src/index.spec.ts
index e2b810d..0d0bdbb 100644
--- a/src/index.spec.ts
+++ b/src/index.spec.ts
@@ -3,7 +3,9 @@ import { Config } from './@types';
 
 describe('config', function () {
   it(`returns the given options`, function () {
-    const options = {};
+    const options: Config = {
+      formats: ['es'],
+    };
     expect(createConfig(options as Config)).toEqual(options);
   });
 });