diff --git a/tests/Models/NullContactElementTest.php b/tests/Models/NullContactElementTest.php
index dc860a8..0c21ba3 100755
--- a/tests/Models/NullContactElementTest.php
+++ b/tests/Models/NullContactElementTest.php
@@ -47,6 +47,6 @@ final class NullContactElementTest extends \PHPUnit\Framework\TestCase
     public function testJsonSerialize() : void
     {
         $null = new NullContactElement(2);
-        self::assertEquals(['id' => 2], $null);
+        self::assertEquals(['id' => 2], $null->jsonSerialize());
     }
 }
diff --git a/tests/Models/NullContactTest.php b/tests/Models/NullContactTest.php
index ab4ef59..510d1a8 100755
--- a/tests/Models/NullContactTest.php
+++ b/tests/Models/NullContactTest.php
@@ -47,6 +47,6 @@ final class NullContactTest extends \PHPUnit\Framework\TestCase
     public function testJsonSerialize() : void
     {
         $null = new NullContact(2);
-        self::assertEquals(['id' => 2], $null);
+        self::assertEquals(['id' => 2], $null->jsonSerialize());
     }
 }
diff --git a/tests/Models/NullProfileTest.php b/tests/Models/NullProfileTest.php
index 3d85082..d00fb18 100755
--- a/tests/Models/NullProfileTest.php
+++ b/tests/Models/NullProfileTest.php
@@ -47,6 +47,6 @@ final class NullProfileTest extends \PHPUnit\Framework\TestCase
     public function testJsonSerialize() : void
     {
         $null = new NullProfile(2);
-        self::assertEquals(['id' => 2], $null);
+        self::assertEquals(['id' => 2], $null->jsonSerialize());
     }
 }