@@ -1,3 +1,4 @@
+import simplejson as json
 from tests.integration.test_base import QuickbooksUnitTestCase
 
 try:
@@ -141,7 +142,7 @@ def test_get_single_object(self, make_req):
 
     @patch('quickbooks.client.QuickBooks.process_request')
     def test_make_request(self, process_request):
-        process_request.return_value = MockResponse()
+        process_request.return_value = MockResponseSimpleJson()
 
         qb_client = client.QuickBooks()
         qb_client.company_id = "1234"
@@ -220,7 +221,7 @@ def test_download_pdf_not_authorized(self, process_request):
     @patch('quickbooks.client.QuickBooks.process_request')
     def test_make_request_file_closed(self, process_request):
         file_path = '/path/to/file.txt'
-        process_request.return_value = MockResponse()
+        process_request.return_value = MockResponseSimpleJson()
         with patch('builtins.open', mock_open(read_data=b'file content')) as mock_file:
             qb_client = client.QuickBooks(auth_client=self.auth_client)
             qb_client.make_request('POST', 
@@ -253,6 +254,18 @@ def json(self):
     def content(self):
         return ''
 
+class MockResponseSimpleJson:
+    def __init__(self, json_data=None, status_code=200):
+        self.json_data = json_data or {}
+        self.status_code = status_code
+
+    @property
+    def text(self):
+        return json.dumps(self.json_data)  # Ensure this uses simplejson if necessary
+
+    def json(self):
+        return self.json_data
+
 
 class MockUnauthorizedResponse(object):
     @property