MAGETWO-60037: User is able to create empty URL key for category which leads to numerous errors

app/code/Magento/CatalogUrlRewrite/Observer/CategoryUrlPathAutogeneratorObserver.php

@@ -5,7 +5,6 @@
  */
 namespace Magento\CatalogUrlRewrite\Observer;
 
-use Doctrine\Instantiator\Exception\InvalidArgumentException;
 use Magento\Catalog\Model\Category;
 use Magento\CatalogUrlRewrite\Model\CategoryUrlPathGenerator;
 use Magento\CatalogUrlRewrite\Service\V1\StoreViewService;

dev/tests/integration/testsuite/Magento/CatalogUrlRewrite/Model/CategoryUrlRewriteGeneratorTest.php

@@ -94,7 +94,7 @@ class CategoryUrlRewriteGeneratorTest extends \PHPUnit_Framework_TestCase
      * @magentoDbIsolation enabled
      * @magentoAppIsolation enabled
      * @param string $urlKey
-     * @dataProvider IncorrectUrlRewritesDataProvider
+     * @dataProvider incorrectUrlRewritesDataProvider
      */
     public function testGenerateUrlRewritesWithIncorrectUrlKey($urlKey)
     {
@@ -112,7 +112,7 @@ class CategoryUrlRewriteGeneratorTest extends \PHPUnit_Framework_TestCase
     /**
      * @return array
      */
-    public function IncorrectUrlRewritesDataProvider()
+    public function incorrectUrlRewritesDataProvider()
     {
         return [
             ['#'],