diff --git a/lib/builder/webpack/postcss.js b/lib/builder/webpack/postcss.js
index ee699b4c3f..fb1b171636 100644
--- a/lib/builder/webpack/postcss.js
+++ b/lib/builder/webpack/postcss.js
@@ -7,6 +7,7 @@ const { cloneDeep } = require('lodash')
 module.exports = function postcssConfig() {
   let config = cloneDeep(this.options.build.postcss)
 
+  /* istanbul ignore if */
   if (!config) {
     return false
   }