Update GitLab CI to run tests

Signed-off-by: João Victor Tozatti Risso <jvtr12@inf.ufpr.br>

.gitlab-ci.yml

@@ -2,13 +2,14 @@ stages:
   - test
 
 before_script:
+  - npm install --global gulp gulp-cli babel babel-cli babel-core babel-register mocha
   - npm install
-  - npm install --global gulp-cli
-  - npm install --global mocha
 
 run_tests:
   stage: test
   script:
-    - gulp && cd build/ && mocha
+    - gulp
+    - cd build
+    - mocha
   tags:
     - node