diff --git a/scripts/build-tests.clj b/scripts/build-tests.clj
index c5cbd2ceb..b2d852b28 100644
--- a/scripts/build-tests.clj
+++ b/scripts/build-tests.clj
@@ -10,10 +10,9 @@
     :output-dir "out"
     :parallel-build false
     :optimizations :none
-    :closure-defines {"uxbox.repo.core.url"
-                      "https://test.uxbox.io/api"}
-    :language-in  :ecmascript5
-    :language-out :ecmascript5
+    :pretty-print true
     :target :nodejs
+    :language-in  :ecmascript6
+    :language-out :ecmascript5
     :verbose true})
   (println "... done. Elapsed" (/ (- (System/nanoTime) start) 1e9) "seconds"))
diff --git a/scripts/watch-tests.clj b/scripts/watch-tests.clj
index ebd9ee120..9826a1d4b 100644
--- a/scripts/watch-tests.clj
+++ b/scripts/watch-tests.clj
@@ -5,9 +5,9 @@
    :output-to "out/tests.js"
    :output-dir "out"
    :parallel-build false
-   :optimizations :simple
+   :optimizations :none
    :pretty-print true
    :target :nodejs
-   :language-in  :ecmascript5
+   :language-in  :ecmascript6
    :language-out :ecmascript5
    :verbose true})