fix: Ensure page token 0 is being passed (#482)

Co-authored-by: octavia-squidington-iii <contact@airbyte.com>

Author: maxi297

airbyte_cdk/sources/declarative/retrievers/simple_retriever.py

@@ -364,7 +364,7 @@ def _read_pages(
         pagination_complete = False
         initial_token = self._paginator.get_initial_token()
         next_page_token: Optional[Mapping[str, Any]] = (
-            {"next_page_token": initial_token} if initial_token else None
+            {"next_page_token": initial_token} if initial_token is not None else None
         )
         while not pagination_complete:
             response = self._fetch_next_page(stream_state, stream_slice, next_page_token)

unit_tests/sources/declarative/retrievers/test_simple_retriever.py

@@ -810,6 +810,42 @@ def retriever_read_pages(_, __, ___):
         cursor.close_slice.assert_called_once_with(stream_slice, None)
 
 
+def test_given_initial_token_is_zero_when_read_records_then_pass_initial_token():
+    record_selector = MagicMock()
+    record_selector.select_records.return_value = []
+    cursor = MagicMock(spec=DeclarativeCursor)
+    paginator = MagicMock()
+    paginator.get_initial_token.return_value = 0
+    paginator.next_page_token.return_value = None
+
+    retriever = SimpleRetriever(
+        name="stream_name",
+        primary_key=primary_key,
+        requester=MagicMock(),
+        paginator=paginator,
+        record_selector=record_selector,
+        stream_slicer=cursor,
+        cursor=cursor,
+        parameters={},
+        config={},
+    )
+    stream_slice = StreamSlice(cursor_slice={}, partition={})
+
+    response = requests.Response()
+    response.status_code = 200
+    response._content = "{}".encode()
+
+    with patch.object(
+        SimpleRetriever,
+        "_fetch_next_page",
+        return_value=response,
+    ) as fetch_next_page_mock:
+        list(retriever.read_records(stream_slice=stream_slice, records_schema={}))
+        fetch_next_page_mock.assert_called_once_with(
+            cursor.get_stream_state(), stream_slice, {"next_page_token": 0}
+        )
+
+
 def _generate_slices(number_of_slices):
     return [{"date": f"2022-01-0{day + 1}"} for day in range(number_of_slices)]