Fail CI if the repo is in a dirty state after building assets

Author: bocharsky-bw

.travis.yml

@@ -2,6 +2,7 @@ language: php
 sudo: false
 
 cache:
+  yarn: true
   directories:
     - $HOME/.composer/cache/files
     - ./bin/.phpunit
@@ -29,6 +30,10 @@ install:
   - composer install
   - ./bin/phpunit install
 
+after_install:
+  #  Fail CI if the repo is in a dirty state after building assets
+  - yarn install && yarn build && git add --all && git diff --staged --exit-code
+
 script:
   - ./bin/phpunit
   # this checks that the source code follows the Symfony Code Syntax rules