Fix running tests (#182)

experimental/babel-preset-env/.travis.yml

@@ -28,3 +28,6 @@ matrix:
   include:
     - node_js: "node"
       env: LINT=true PKG_CMD="npm"
+  exclude:
+    - node_js: "4"
+      env: PKG_CMD="yarn"

experimental/babel-preset-env/test/fixtures.js

@@ -1 +1,3 @@
-require("babel-helper-plugin-test-runner")(__dirname);
+import runner from "babel-helper-plugin-test-runner";
+
+runner(__dirname);