diff --git a/src/__tests__/runTransformation.spec.ts b/src/__tests__/runTransformation.spec.ts
index 7320104..46add0b 100644
--- a/src/__tests__/runTransformation.spec.ts
+++ b/src/__tests__/runTransformation.spec.ts
@@ -39,7 +39,7 @@ const addUseStrict: Transform = (file, api, options) => {
   body[0].comments = body[1].comments
   delete body[1].comments
 
-  return root.toSource(options.printOptions || { quote: 'single' })
+  return root.toSource(options.printOptions || { quote: 'single', lineTerminator: '\n' })
 }
 
 describe('run-transformation', () => {