diff --git a/tests/Models/Driver/NullDriverTest.php b/tests/Models/Driver/NullDriverTest.php
index 43e5f84..5a354a2 100644
--- a/tests/Models/Driver/NullDriverTest.php
+++ b/tests/Models/Driver/NullDriverTest.php
@@ -47,6 +47,6 @@ final class NullDriverTest extends \PHPUnit\Framework\TestCase
     public function testJsonSerialize() : void
     {
         $null = new NullDriver(2);
-        self::assertEquals(['id' => 2], $null);
+        self::assertEquals(['id' => 2], $null->jsonSerialize());
     }
 }
\ No newline at end of file
diff --git a/tests/Models/NullInspectionTest.php b/tests/Models/NullInspectionTest.php
index 18ae22c..5fbe342 100644
--- a/tests/Models/NullInspectionTest.php
+++ b/tests/Models/NullInspectionTest.php
@@ -47,6 +47,6 @@ final class NullInspectionTest extends \PHPUnit\Framework\TestCase
     public function testJsonSerialize() : void
     {
         $null = new NullInspection(2);
-        self::assertEquals(['id' => 2], $null);
+        self::assertEquals(['id' => 2], $null->jsonSerialize());
     }
 }
\ No newline at end of file
diff --git a/tests/Models/NullVehicleTest.php b/tests/Models/NullVehicleTest.php
index e1627a6..242e4b6 100644
--- a/tests/Models/NullVehicleTest.php
+++ b/tests/Models/NullVehicleTest.php
@@ -47,6 +47,6 @@ final class NullVehicleTest extends \PHPUnit\Framework\TestCase
     public function testJsonSerialize() : void
     {
         $null = new NullVehicle(2);
-        self::assertEquals(['id' => 2], $null);
+        self::assertEquals(['id' => 2], $null->jsonSerialize());
     }
 }
\ No newline at end of file