Copy installed modules from build to test steps.

.circleci/config.yml

@@ -24,12 +24,11 @@ jobs:
       - image: circleci/node:4.8.2
     steps:
       - checkout
+      - restore_cache:
+          key: dependency-cache-{{ checksum "package.json" }}
       - run:
           name: Test
           command: npm test
-      - store_artifacts:
-          path: test-results.xml
-          prefix: tests
 
 workflows:
   version: 2