diff --git a/tests/Models/NullEmailL11nTest.php b/tests/Models/NullEmailL11nTest.php
index 5f87192..6020fb5 100644
--- a/tests/Models/NullEmailL11nTest.php
+++ b/tests/Models/NullEmailL11nTest.php
@@ -47,6 +47,6 @@ final class NullEmailL11nTest extends \PHPUnit\Framework\TestCase
     public function testJsonSerialize() : void
     {
         $null = new NullEmailL11n(2);
-        self::assertEquals(['id' => 2], $null);
+        self::assertEquals(['id' => 2], $null->jsonSerialize());
     }
 }
diff --git a/tests/Models/NullEmailTest.php b/tests/Models/NullEmailTest.php
index ab62bdf..2c9af16 100644
--- a/tests/Models/NullEmailTest.php
+++ b/tests/Models/NullEmailTest.php
@@ -47,6 +47,6 @@ final class NullEmailTest extends \PHPUnit\Framework\TestCase
     public function testJsonSerialize() : void
     {
         $null = new NullEmail(2);
-        self::assertEquals(['id' => 2], $null);
+        self::assertEquals(['id' => 2], $null->jsonSerialize());
     }
 }