Put npm test behind the RUN_TESTS flag

Dockerfile

@@ -95,8 +95,13 @@ RUN npm install -g webpack
 RUN webpack
 
 # Run front-end tests
+ARG RUN_TESTS=true
+ENV RUN_TESTS ${RUN_TESTS}
+
 ADD karma.conf.js karma.conf.js
-RUN npm test
+RUN if [ "$RUN_TESTS" = true ]; then \
+        npm test; \
+    fi
 
 # Install Grunt
 RUN npm install -g grunt-cli
@@ -151,12 +156,9 @@ ADD .git/HEAD GIT_HEAD
 ADD . .
 
 # Run the tests
-ARG RUN_TESTS=true
-ENV RUN_TESTS ${RUN_TESTS}
 ENV RUN_ACI_TESTS False
 ADD requirements-tests.txt requirements-tests.txt
 
-
 RUN if [ "$RUN_TESTS" = true ]; then \
       venv/bin/pip install -r requirements-tests.txt ;\
     fi