diff --git a/tests/Models/NullSessionElementTest.php b/tests/Models/NullSessionElementTest.php
index 65a068b..2423cab 100755
--- a/tests/Models/NullSessionElementTest.php
+++ b/tests/Models/NullSessionElementTest.php
@@ -47,6 +47,6 @@ final class NullSessionElementTest extends \PHPUnit\Framework\TestCase
     public function testJsonSerialize() : void
     {
         $null = new NullSessionElement(2);
-        self::assertEquals(['id' => 2], $null);
+        self::assertEquals(['id' => 2], $null->jsonSerialize());
     }
 }
diff --git a/tests/Models/NullSessionTest.php b/tests/Models/NullSessionTest.php
index d45d388..1467d44 100755
--- a/tests/Models/NullSessionTest.php
+++ b/tests/Models/NullSessionTest.php
@@ -47,6 +47,6 @@ final class NullSessionTest extends \PHPUnit\Framework\TestCase
     public function testJsonSerialize() : void
     {
         $null = new NullSession(2);
-        self::assertEquals(['id' => 2], $null);
+        self::assertEquals(['id' => 2], $null->jsonSerialize());
     }
 }