diff --git a/composer.json b/composer.json
index 38c59d8..06b10cb 100644
--- a/composer.json
+++ b/composer.json
@@ -12,11 +12,14 @@
     ],
     "config" : {
         "sort-packages": true,
-        "bin-dir": "bin"
+        "bin-dir": "bin",
+        "preferred-install": {
+            "webonyx/graphql-php": "source"
+        }
     },
     "require": {
-        "php": "^5.4|~7.0",
-        "webonyx/graphql-php": "^0.11.2"
+        "php": "^5.5|~7.0",
+        "webonyx/graphql-php": "^0.11.2|^0.12.0"
     },
     "require-dev": {
         "fabpot/php-cs-fixer": "^1.11",
diff --git a/tests/AbstractStarWarsTest.php b/tests/AbstractStarWarsTest.php
index 5bc148c..b6a52e6 100644
--- a/tests/AbstractStarWarsTest.php
+++ b/tests/AbstractStarWarsTest.php
@@ -11,6 +11,7 @@
 
 namespace Overblog\GraphQLGenerator\Tests;
 
+use GraphQL\Error\Debug;
 use GraphQL\GraphQL;
 use GraphQL\Type\Schema;
 use Overblog\GraphQLGenerator\Tests\Generator\AbstractTypeGeneratorTest;
@@ -45,7 +46,8 @@ public function setUp()
      */
     protected function assertValidQuery($query, $expected, $variables = null)
     {
-        $actual = GraphQL::executeQuery($this->schema, $query, null, null, $variables)->toArray();
+        $actual = GraphQL::executeQuery($this->schema, $query, null, null, $variables)
+            ->toArray(Debug::INCLUDE_DEBUG_MESSAGE|Debug::INCLUDE_TRACE);
         $expected = ['data' => $expected];
         $this->assertEquals($expected, $actual, json_encode($actual));
     }