Use global environment variable in Travis build matrix

Author: alessfg

.travis.yml

@@ -3,32 +3,33 @@ sudo: required
 services:
   - docker
 env:
-  - distribution: centos
-    version: 6
-  - distribution: centos
-    version: 7
-  - distribution: ubuntu
-    version: trusty
-  - distribution: ubuntu
-    version: xenial
-  - distribution: debian
-    version: jessie
-  - distribution: debian
-    version: stretch
-tests:
-  - opensource
-  - template
-  - upload
+  global:
+    - playbook: opensource
+    - playbook: template
+    - playbook: upload
+  matrix:
+    - distribution: centos
+      version: 6
+    - distribution: centos
+      version: 7
+    - distribution: ubuntu
+      version: trusty
+    - distribution: ubuntu
+      version: xenial
+    - distribution: debian
+      version: jessie
+    - distribution: debian
+      version: stretch
 before_install:
   - 'sudo docker pull ${distribution}:${version}'
   - 'sudo docker build --no-cache --rm --file=tests/dockerfiles/Dockerfile.${distribution}-${version} --tag=${distribution}-${version}:ansible tests'
 script:
   - container_id=$(mktemp)
   - 'sudo docker run --detach --privileged -v /sys/fs/cgroup:/sys/fs/cgroup:ro --volume="${PWD}":/etc/ansible/roles/ansible-role-nginx:ro ${distribution}-${version}:ansible > "${container_id}"'
-  - 'sudo docker exec "$(cat ${container_id})" env ANSIBLE_FORCE_COLOR=1 ansible-playbook -v /etc/ansible/roles/ansible-role-nginx/tests/playbooks/nginx-${tests}.yml --syntax-check'
-  - 'sudo docker exec "$(cat ${container_id})" env ANSIBLE_FORCE_COLOR=1 ansible-playbook -v /etc/ansible/roles/ansible-role-nginx/tests/playbooks/nginx-${tests}.yml'
+  - 'sudo docker exec "$(cat ${container_id})" env ANSIBLE_FORCE_COLOR=1 ansible-playbook -v /etc/ansible/roles/ansible-role-nginx/tests/playbooks/nginx-${playbook}.yml --syntax-check'
+  - 'sudo docker exec "$(cat ${container_id})" env ANSIBLE_FORCE_COLOR=1 ansible-playbook -v /etc/ansible/roles/ansible-role-nginx/tests/playbooks/nginx-${playbook}.yml'
   - >
-    sudo docker exec "$(cat ${container_id})" env ANSIBLE_FORCE_COLOR=1 ansible-playbook -v /etc/ansible/roles/ansible-role-nginx/tests/playbooks/nginx-${tests}.yml
+    sudo docker exec "$(cat ${container_id})" env ANSIBLE_FORCE_COLOR=1 ansible-playbook -v /etc/ansible/roles/ansible-role-nginx/tests/playbooks/nginx-${playbook}.yml
     | grep -q 'changed=0.*failed=0'
     && (echo 'Idempotence test: pass' && exit 0)
     || (echo 'Idempotence test: fail' && exit 1)