Fix client request on POST poll (new poll).

tests/Functional/PollControllerTest.php

@@ -129,8 +129,7 @@ class PollControllerTest extends WebTestCase {
         'App\DataFixtures\AppPollFixtures'
     ));
 
-    $client->request('POST', '/api/v1/poll/', [
-        'json' => [
+    $data = [
         "title" => "Fromage ou dessert ? ",
         "description" => "Votre plat préféré",
         "creation_date" => "2048-04-25T16:19:48+02:00",
@@ -152,8 +151,11 @@ class PollControllerTest extends WebTestCase {
             ]
         ],
         "default_expiracy_days_from_now" => 365
-        ]
-    ]);
+    ];
+
+    $client->request('POST', '/api/v1/poll/', [
+        'json' => $data
+    ], [], [], json_encode($data));
 
     $response = $client->getResponse();
     $this->assertEquals(201, $response->getStatusCode());