Se movio phpunit desde el require al require-dev

composer.json

@@ -141,7 +141,6 @@
         "jms/serializer": "^1.9.0",
         "jms/serializer-bundle": "^1.5.0",
         "php-amqplib/rabbitmq-bundle": "^1.12",
-        "phpunit/phpunit": "^6.4",
         "sensio/distribution-bundle": "^5.0.21",
         "sensio/framework-extra-bundle": "^3.0.2",
         "sonata-project/admin-bundle": "dev-bf4681",
@@ -157,6 +156,7 @@
         "voryx/restgeneratorbundle": "dev-master"
     },
     "require-dev": {
+        "phpunit/phpunit": "^6.4",
         "sensio/generator-bundle": "^3.0",
         "symfony/phpunit-bridge": "^3.3"
     },