exec_resize is incorrectly passing param as json

docker/client.py

@@ -567,14 +567,11 @@ class Client(requests.Session):
             raise errors.InvalidVersion('Exec is not supported in API < 1.15')
         if isinstance(exec_id, dict):
             exec_id = exec_id.get('Id')
-        data = {
-            'h': height,
-            'w': width
-        }
-        res = self._post_json(
-            self._url('/exec/{0}/resize'.format(exec_id)), data
-        )
-        res.raise_for_status()
+
+        params = {'h': height, 'w': width}
+        url = self._url("/exec/{0}/resize".format(exec_id))
+        res = self._post(url, params=params)
+        self._raise_for_status(res)
 
     def exec_start(self, exec_id, detach=False, tty=False, stream=False):
         if utils.compare_version('1.15', self._version) < 0:

tests/test.py

@@ -1662,22 +1662,10 @@ class DockerClientTest(Cleanup, base.BaseTestCase):
         except Exception as e:
             self.fail('Command should not raise exception: {0}'.format(e))
 
-        args = fake_request.call_args
-        self.assertEqual(
-            args[0][0], url_prefix + 'exec/{0}/resize'.format(
-                fake_api.FAKE_EXEC_ID
-            )
-        )
-
-        self.assertEqual(
-            json.loads(args[1]['data']), {
-                'h': 20,
-                'w': 60,
-            }
-        )
-
-        self.assertEqual(
-            args[1]['headers'], {'Content-Type': 'application/json'}
+        fake_request.assert_called_with(
+            url_prefix + 'exec/{0}/resize'.format(fake_api.FAKE_EXEC_ID),
+            params={'h': 20, 'w': 60},
+            timeout=DEFAULT_TIMEOUT_SECONDS
         )
 
     def test_pause_container(self):