chore: fix js tests

umap/static/umap/test/index.html

@@ -123,6 +123,7 @@
     <div id="mocha"></div>
     <div id="map"></div>
     <script>
+      window.addEventListener('DOMContentLoaded', () => {
         var runner = (window.mochaPhantomJS || window.mocha).run(function (failures) {
           if (window.location.search.indexOf('debug') === -1)
             qs('#mocha').style.display = 'block'
@@ -138,6 +139,7 @@
             console.log(message)
           }
         }
+      })
     </script>
   </body>
 </html>