Maybe stages will help?

.gitlab-ci.yml

@@ -1,32 +1,36 @@
 # Composer stores all downloaded packages in the vendor/ directory.
 # Do not use the following if the vendor/ directory is commited to
 # your git repository.
-cache:
-  paths:
-  - vendor/
 
 services:
     - redis:latest
 
-test:7:
+stages:
+    - test
+
+test:
+    test:7:
+        stage: test
         before_script:
-      - bash build/docker_install.sh > /dev/null
+          - sh build/docker_install.sh > /dev/null
           - curl -sS https://getcomposer.org/installer | php
           - php composer.phar install --no-dev
         image: php:7-alpine
         script:
           - phpunit -c build --coverage-text --colors=never
 
-test:7.1:
+    test:7.1:
+        stage: test
         before_script:
-      - bash build/docker_install.sh > /dev/null
+          - sh build/docker_install.sh > /dev/null
           - curl -sS https://getcomposer.org/installer | php
           - php composer.phar install --no-dev
         image: php:7.1-alpine
         script:
           - phpunit -c build --coverage-text --colors=never
 
-test:hhvm:
+    test:hhvm:
+        stage: test
         allow_failure: true
         before_script:
           - /usr/local/bin/composer self-update