diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/tests/RequestTest.php b/samples/openapi3/client/petstore/php/SwaggerClient-php/tests/RequestTest.php
index cb1d9d62fb7e..2fd9ab8831f2 100644
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/tests/RequestTest.php
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/tests/RequestTest.php
@@ -3,12 +3,12 @@
 namespace Swagger\Client;
 
 use Swagger\Client\Api\FakeApi;
+use Swagger\Client\Model\Body4;
 
 require_once __DIR__ . '/FakeHttpClient.php';
 
 class RequestTest extends \PHPUnit_Framework_TestCase
 {
-
     /** @var FakeApi */
     private $api;
     /** @var  FakeHttpClient */
@@ -22,15 +22,22 @@ class RequestTest extends \PHPUnit_Framework_TestCase
 
     public function testFormDataEncodingToJson()
     {
-        $this->api->testJsonFormData('value', 'value2');
+        $this->api->testJsonFormData(
+            new Body4(['param' => 'value', 'param2' => 'value2'])
+        );
 
         $request = $this->fakeClient->getLastRequest();
         $contentType = $request->getHeader('Content-Type');
         $this->assertEquals(['application/json'], $contentType);
 
         $requestContent = $request->getBody()->getContents();
+        $expected = <<<__EOS__
+{
+    "param": "value",
+    "param2": "value2"
+}
+__EOS__;
 
-        $expected = json_encode(['param' => 'value', 'param2' => 'value2']);
         $this->assertEquals($expected, $requestContent);
     }
 }