Fixes #42: Fails in --check mode.

.travis.yml

@@ -29,6 +29,9 @@ script:
     && (echo 'Idempotence test: pass' && exit 0)
     || (echo 'Idempotence test: fail' && exit 1)
 
+  # Run the role/playbook in --check mode.
+  - "ansible-playbook -i tests/inventory tests/$SITE --check"
+
   # Make sure PHP is running.
   - >
     php -v

tasks/main.yml

@@ -34,6 +34,7 @@
   shell: php -r "echo PHP_VERSION;"
   register: php_version
   changed_when: false
+  always_run: yes
 
 - name: Disable opcache if PHP version is < 5.5.
   set_fact: