diff --git a/tests/Monolog/Formatter/JsonFormatterTest.php b/tests/Monolog/Formatter/JsonFormatterTest.php
index dbc2a08c..17a3ba82 100644
--- a/tests/Monolog/Formatter/JsonFormatterTest.php
+++ b/tests/Monolog/Formatter/JsonFormatterTest.php
@@ -189,8 +189,8 @@ class JsonFormatterTest extends TestCase
     {
         $formatter = new JsonFormatter(JsonFormatter::BATCH_MODE_JSON, false);
         $record = $this->getRecord();
-        $record['context'] = ['field_resource' => curl_init()];
-        $this->assertEquals('{"message":"test","context":{"field_resource":"[resource(curl)]"},"level":300,"level_name":"WARNING","channel":"test","datetime":"'.$record['datetime']->format('Y-m-d\TH:i:s.uP').'","extra":{}}', $formatter->format($record));
+        $record['context'] = ['field_resource' => opendir(__DIR__)];
+        $this->assertEquals('{"message":"test","context":{"field_resource":"[resource(stream)]"},"level":300,"level_name":"WARNING","channel":"test","datetime":"'.$record['datetime']->format('Y-m-d\TH:i:s.uP').'","extra":{}}', $formatter->format($record));
     }
 
     /**