Issue 6890 - run npm tests in parallel (PENDING)

.gitlab-ci.yml

 # This file is part of Adblock Plus <https://adblockplus.org/>,
 # Copyright (C) 2006-present eyeo GmbH
 #
 # Adblock Plus is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 3 as
 # published by the Free Software Foundation.
 #
 # Adblock Plus is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
 
 stages:
   - prepare
   - test
 
-prepare-dependencies:
-  stage: prepare
-  script:
+.dependencies:
+  script: &dependencies
     - mkdir -p .git/info
     - pip install --user Jinja2 cryptography
     - python ensure_dependencies.py
-    - npm install
+    - "[ -d node_modules ] || npm install"
+
+.test_template: &test_template
+  stage: test
+  before_script: *dependencies
+  cache:
+    key: cache_$CI_COMMIT_SHA
+    paths:
+      - ./
+    policy: pull
+
+
+prepare-dependencies:
+  stage: prepare
+  script: *dependencies
   cache:
     key: cache_$CI_COMMIT_SHA
     paths:
       - ./
     policy: push
 
-
-.test_template: &test_template
-  stage: test
-  cache:
-    key: cache_$CI_COMMIT_SHA
-    paths:
-      - ./
-    policy: pull
-
 tests:gecko:
   <<: *test_template
   script:
-    - npm install
-    - npm test -- -g gecko
+    - npm run test-only -- -g gecko
 
 tests:chrome:
   <<: *test_template
   script:
-    - npm install
-    - xvfb-run npm test -- -g chrome
+    - xvfb-run npm run test-only -- -g chrome
+
+lint:
+  <<: *test_template
+  script:
+    - npm run lint