diff --git a/packages/replace/test/fixtures/form/observe-plugin-options/_config.js b/packages/replace/test/fixtures/form/observe-plugin-options/_config.js
index 5d1b7ba76..f472fef74 100755
--- a/packages/replace/test/fixtures/form/observe-plugin-options/_config.js
+++ b/packages/replace/test/fixtures/form/observe-plugin-options/_config.js
@@ -6,6 +6,7 @@ module.exports = {
     sourcemap: true,
     sourceMap: true,
     include: '**/input.js',
-    exclude: 'node_modules/**'
+    exclude: 'node_modules/**',
+    preventAssignment: false
   }
 };