nullable slug must not be null if base field has "0"

Author: vetalt

lib/Gedmo/Sluggable/SluggableListener.php

@@ -381,7 +381,7 @@ private function generateSlug(SluggableAdapter $ea, $object)
                     $slug = substr($slug, 0, $mapping['length']);
                 }
 
-                if (isset($mapping['nullable']) && $mapping['nullable'] && !$slug) {
+                if (isset($mapping['nullable']) && $mapping['nullable'] && strlen($slug) === 0) {
                     $slug = null;
                 }
 

tests/Gedmo/Sluggable/Issue/Issue131Test.php

@@ -46,6 +46,20 @@ public function testSlugGeneration()
         $this->assertNull($test2->getSlug());
     }
 
+    /**
+     * @test
+     */
+    public function shouldHandleOnlyZeroInSlug()
+    {
+        $article = new Article();
+        $article->setTitle('0');
+
+        $this->em->persist($article);
+        $this->em->flush();
+
+        $this->assertEquals('0', $article->getSlug());
+    }
+
     protected function getUsedEntityFixtures()
     {
         return array(