utils fix for p_i, line_items and invoices

tests/test_all_fields.py

@@ -282,6 +282,7 @@
         'hosted_invoice_url', # expect https://invoice.stripe.com/i/acct_14zvmQDcBSxinnbL/test...zcy0200wBekbjGw?s=ap
         'invoice_pdf',        # get    https://invoice.stripe.com/i/acct_14zvmQDcBSxinnbL/test...DE102006vZ98t5I?s=ap
         'payment_settings',   # 'default_mandate' subfield unexpectedly present
+        'subscription_details'
     },
     'plans': set(),
     'invoice_line_items': set()

tests/utils.py

@@ -475,6 +475,9 @@ def create_object(stream):
             )
         elif stream == 'invoices':
             # Invoices requires the customer has an item associated with them
+            # Creating invoice record using olderversion because it generates invoice.lines data 
+            # at the time of record creation itself
+            stripe_client.api_version = '2020-08-27'
             item = client["{}_items".format(stream[:-1])].create(
                 amount=random.randint(1, 10000),
                 currency="usd",