[EAV] keep unit test code consistency

Author: ftwbzhao

More/EAV/Tests/ValueTest.php

@@ -40,6 +40,7 @@ public function testSetGetAttribute()
         $value->setName('Silver');
         $this->assertSame($attribute, $value->getAttribute());
 
-        $this->assertSame($attribute, $value->setAttribute($attribute)->getAttribute());
+        $value->setAttribute($attribute);
+        $this->assertSame($attribute, $value->getAttribute());
     }
 }