[FE-5985] Error when configuring start_ts and cursor at the same time

fauna/client/client.py

@@ -555,6 +555,10 @@ def __init__(self, http_client: HTTPClient, headers: Dict[str, str],
     self.last_cursor = None
     self._ctx = self._create_stream()
 
+    if opts.start_ts is not None and opts.cursor is not None:
+      err_msg = "Only one of 'start_ts' or 'cursor' can be defined in the StreamOptions."
+      raise TypeError(err_msg)
+
   def __enter__(self):
     return self
 
@@ -671,6 +675,10 @@ def __init__(self, http: HTTPClient, headers: Dict[str, str], endpoint: str,
     self._request: Dict[str, Any] = {"token": token.token}
     self._is_done = False
 
+    if opts.start_ts is not None and opts.cursor is not None:
+      err_msg = "Only one of 'start_ts' or 'cursor' can be defined in the ChangeFeedOptions."
+      raise TypeError(err_msg)
+
     if opts.page_size is not None:
       self._request["page_size"] = opts.page_size
 

tests/integration/test_change_feeds.py

@@ -115,6 +115,17 @@ def test_change_feed_cursor(client, a_collection):
   assert nums == list(range(1, 64))
 
 
+def test_rejects_when_both_start_ts_and_cursor_provided(scoped_client):
+  scoped_client.query(fql("Collection.create({name: 'Product'})"))
+
+  response = scoped_client.query(fql("Product.all().toStream()"))
+  stream_token = response.data
+
+  with pytest.raises(TypeError):
+    opts = ChangeFeedOptions(cursor="abc1234==", start_ts=response.txn_ts)
+    scoped_client.change_feed(stream_token, opts)
+
+
 def test_change_feed_reusable_iterator(client, a_collection):
   feed = client.change_feed(
       fql("${col}.all().map(.n).toStream()", col=a_collection))

tests/integration/test_stream.py

@@ -229,6 +229,17 @@ def test_rejects_cursor_with_fql_query(scoped_client):
     scoped_client.stream(fql("Collection.create({name: 'Product'})"), opts)
 
 
+def test_rejects_when_both_start_ts_and_cursor_provided(scoped_client):
+  scoped_client.query(fql("Collection.create({name: 'Product'})"))
+
+  response = scoped_client.query(fql("Product.all().toStream()"))
+  stream_token = response.data
+
+  with pytest.raises(TypeError):
+    opts = StreamOptions(cursor="abc1234==", start_ts=response.txn_ts)
+    scoped_client.stream(stream_token, opts)
+
+
 def test_handle_status_events(scoped_client):
   scoped_client.query(fql("Collection.create({name: 'Product'})"))