trying to not include require-dev in composer.lock, to not install it by default and run composer update phpunit/phpunit in Travis, as phpunit needs different version for PHP versions we support

.travis.yml

@@ -32,10 +32,12 @@ before_script:
   - sudo apt-get update -qq
   - sudo apt-get install -y myrepos
   - mr --trust-all --stats up
+  # installing phpunit in version suitable for used PHP version
+  - composer.phar update phpunit/phpunit
 
 script:
-  ./doc/php_syntax_check.sh
-  ./doc/test-cli.php
+  - ./doc/php_syntax_check.sh
+  - ./doc/test-cli.php
 
 cache:
   directories:

composer.json

@@ -35,6 +35,6 @@
 		"npm-asset/gridster":"0.5.*"
 	},
 	"require-dev": {
-		"phpunit/phpunit": "5.4.*"
+		"phpunit/phpunit": "~4.8|~5.4"
 	}
 }