diff --git a/packages/legacy/tools/src/utils/mocha/mocha.ts b/packages/legacy/tools/src/utils/mocha/mocha.ts
index 23cf7a95a42..c17c2bc7732 100644
--- a/packages/legacy/tools/src/utils/mocha/mocha.ts
+++ b/packages/legacy/tools/src/utils/mocha/mocha.ts
@@ -19,6 +19,7 @@ class Mocha {
    */
   public static test({ files }: { files: Array<string> }) {
     Babel({
+      only: ['../../**/*.js', '../../**/*.ts'],
       extensions: ['.js', '.ts'],
       sourceMaps: true,
     });