[ci] pipelines and unit tests

.gitlab-ci.yml

@@ -3,10 +3,23 @@ default:
   before_script:
     - yarn install
 
+stages:
+  - build
+  - test
+  - lint
+
 build:
+  stage: build
   script:
     - yarn build
 
+test:
+  stage: test
+  script:
+    - yarn test
+
 lint:
+  stage: lint
+  allow_failure: true
   script:
     - yarn lint