diff --git a/umap/static/umap/test/_pre.js b/umap/static/umap/test/_pre.js
index b46bd687..b8547fb9 100644
--- a/umap/static/umap/test/_pre.js
+++ b/umap/static/umap/test/_pre.js
@@ -1,3 +1,6 @@
+window.assert = chai.assert
+window.expect = chai.expect
+
 var qs = function (selector, element) {
   return (element || document).querySelector(selector)
 }
diff --git a/umap/static/umap/test/index.html b/umap/static/umap/test/index.html
index be656135..c3f5da40 100644
--- a/umap/static/umap/test/index.html
+++ b/umap/static/umap/test/index.html
@@ -64,8 +64,6 @@
         ignoreLeaks: true,
       })
       chai.config.includeStack = true
-      var assert = chai.assert
-      var expect = chai.expect
     </script>
     <script src="./_pre.js"></script>
     <script src="./Map.js"></script>