diff --git a/tests/Models/NullSurveyTemplateElementL11nTest.php b/tests/Models/NullSurveyTemplateElementL11nTest.php
index e8f5608..b1b7744 100755
--- a/tests/Models/NullSurveyTemplateElementL11nTest.php
+++ b/tests/Models/NullSurveyTemplateElementL11nTest.php
@@ -47,6 +47,6 @@ final class NullSurveyTemplateElementL11nTest extends \PHPUnit\Framework\TestCas
     public function testJsonSerialize() : void
     {
         $null = new NullSurveyTemplateElementL11n(2);
-        self::assertEquals(['id' => 2], $null);
+        self::assertEquals(['id' => 2], $null->jsonSerialize());
     }
 }
diff --git a/tests/Models/NullSurveyTemplateElementTest.php b/tests/Models/NullSurveyTemplateElementTest.php
index 2f619c1..63dba3d 100755
--- a/tests/Models/NullSurveyTemplateElementTest.php
+++ b/tests/Models/NullSurveyTemplateElementTest.php
@@ -47,6 +47,6 @@ final class NullSurveyTemplateElementTest extends \PHPUnit\Framework\TestCase
     public function testJsonSerialize() : void
     {
         $null = new NullSurveyTemplateElement(2);
-        self::assertEquals(['id' => 2], $null);
+        self::assertEquals(['id' => 2], $null->jsonSerialize());
     }
 }
diff --git a/tests/Models/NullSurveyTemplateL11nTest.php b/tests/Models/NullSurveyTemplateL11nTest.php
index 7a8a3da..633d58b 100755
--- a/tests/Models/NullSurveyTemplateL11nTest.php
+++ b/tests/Models/NullSurveyTemplateL11nTest.php
@@ -47,6 +47,6 @@ final class NullSurveyTemplateL11nTest extends \PHPUnit\Framework\TestCase
     public function testJsonSerialize() : void
     {
         $null = new NullSurveyTemplateL11n(2);
-        self::assertEquals(['id' => 2], $null);
+        self::assertEquals(['id' => 2], $null->jsonSerialize());
     }
 }
diff --git a/tests/Models/NullSurveyTemplateLabelL11nTest.php b/tests/Models/NullSurveyTemplateLabelL11nTest.php
index 26e8e90..e57a65d 100755
--- a/tests/Models/NullSurveyTemplateLabelL11nTest.php
+++ b/tests/Models/NullSurveyTemplateLabelL11nTest.php
@@ -47,6 +47,6 @@ final class NullSurveyTemplateLabelL11nTest extends \PHPUnit\Framework\TestCase
     public function testJsonSerialize() : void
     {
         $null = new NullSurveyTemplateLabelL11n(2);
-        self::assertEquals(['id' => 2], $null);
+        self::assertEquals(['id' => 2], $null->jsonSerialize());
     }
 }
diff --git a/tests/Models/NullSurveyTemplateTest.php b/tests/Models/NullSurveyTemplateTest.php
index 25693f6..1051d7b 100755
--- a/tests/Models/NullSurveyTemplateTest.php
+++ b/tests/Models/NullSurveyTemplateTest.php
@@ -47,6 +47,6 @@ final class NullSurveyTemplateTest extends \PHPUnit\Framework\TestCase
     public function testJsonSerialize() : void
     {
         $null = new NullSurveyTemplate(2);
-        self::assertEquals(['id' => 2], $null);
+        self::assertEquals(['id' => 2], $null->jsonSerialize());
     }
 }