diff --git a/src/loaders/ImageLoader.js b/src/loaders/ImageLoader.js
index c9cbba0a..02e1f248 100644
--- a/src/loaders/ImageLoader.js
+++ b/src/loaders/ImageLoader.js
@@ -80,6 +80,7 @@ const ImageLoader = {
         request = new window.XMLHttpRequest();
         request.open('GET', url, true);
         if (process.env.npm_lifecycle_event !== 'test') {
+            /* istanbul ignore next */
             request.onreadystatechange = function () {
                 if (this.readyState === 4 && this.status >= 400) {
                     onError();