api_types/model: Fetch stream email address from endpoint if required.

Updated method to retrieve the stream email address from stream_dict,
fetching from a new endpoint introduced in ZFL 226 if not available in
the dict (ensuring compatibility across server versions).

Introduced a new method to call the endpoint for fetching the email address.

Added tests. Updated api_types.

Author: rsashank

tests/model/test_model.py

@@ -6,6 +6,7 @@
 
 import pytest
 from pytest import param as case
+from pytest_mock import MockerFixture
 from zulip import Client, ZulipError
 
 from zulipterminal.config.symbols import STREAM_TOPIC_SEPARATOR
@@ -564,25 +565,73 @@ def test_topics_in_stream(self, mocker, model, topics_index, fetched, stream_id=
         assert model.index["topics"][stream_id] is not return_value
 
     @pytest.mark.parametrize(
-        "email_address_stream_dict, expected_return_value",
+        "response, expected_return_value",
         [
-            ({"email_address": "[email protected]"}, "[email protected]"),
-            ({}, None),
+            (
+                {"result": "success", "msg": "", "email": "[email protected]"},
+                "[email protected]",
+            ),
+            (
+                {"result": "error", "msg": "Invalid stream ID", "code": "BAD_REQUEST"},
+                None,
+            ),
+        ],
+        ids=["valid_email_returned", "no_email_returned"],
+    )
+    def test__fetch_stream_email_from_endpoint(
+        self,
+        mocker: MockerFixture,
+        model: Any,
+        response: Dict[str, str],
+        expected_return_value: Optional[str],
+        stream_id: int = 1,
+    ) -> None:
+        self.client.call_endpoint = mocker.Mock(return_value=response)
+
+        result = model._fetch_stream_email_from_endpoint(stream_id)
+
+        self.client.call_endpoint.assert_called_once_with(
+            f"/streams/{stream_id}/email_address", method="GET"
+        )
+        assert result == expected_return_value
+
+    @pytest.mark.parametrize(
+        "email_address_stream_dict, email_fetch_response, "
+        "expected_fetched, expected_return_value",
+        [
+            (
+                {"email_address": "[email protected]"},
+                None,
+                False,
+                "[email protected]",
+            ),
+            ({}, "[email protected]", True, "[email protected]"),
+            ({}, None, True, None),
         ],
         ids=[
             "email_present_in_dict:ZFL<226",
-            "email_absent_from_dict:ZFL>=226",
+            "email_absent_from_dict_and_fetched_ok:ZFL>=226",
+            "email_absent_from_dict_and_fetch_failed:ZFL>=226",
         ],
     )
     def test_get_stream_email_address(
         self,
+        mocker: MockerFixture,
         model: Any,
         email_address_stream_dict: Dict[str, str],
+        email_fetch_response: Optional[str],
+        expected_fetched: bool,
         expected_return_value: Optional[str],
         stream_id: int = 1,
     ) -> None:
         model.stream_dict[stream_id] = email_address_stream_dict
+        model._fetch_stream_email_from_endpoint = mocker.Mock(
+            return_value=email_fetch_response
+        )
+
         result = model.get_stream_email_address(stream_id)
+
+        assert model._fetch_stream_email_from_endpoint.called == expected_fetched
         assert result == expected_return_value
 
     # pre server v3 provide user_id or id as a property within user key

zulipterminal/api_types.py

@@ -237,7 +237,7 @@ class Subscription(TypedDict):
     push_notifications: Optional[bool]
     audible_notifications: Optional[bool]
     pin_to_top: bool
-    email_address: str
+    email_address: NotRequired[str]  # Replaced by new endpoint in Zulip 7.5 (ZFL 226)
 
     is_muted: bool
 

zulipterminal/model.py

@@ -906,16 +906,30 @@ def topics_in_stream(self, stream_id: int) -> List[str]:
 
         return list(self.index["topics"][stream_id])
 
+    def _fetch_stream_email_from_endpoint(self, stream_id: int) -> Optional[str]:
+        """
+        Endpoint added in Zulip 7.5 (ZFL 226)
+        """
+        url = f"/streams/{stream_id}/email_address"
+
+        response = self.client.call_endpoint(url, method="GET")
+
+        if response.get("result") == "success":
+            email_address = response.get("email", "")
+            return str(email_address)
+        return None
+
     def get_stream_email_address(self, stream_id: int) -> Optional[str]:
         """
         Returns the stream email address, or None if it is unavailable.
+        Beyond Zulip 7.5 / ZFL226, this requires a call to the server.
         """
         if stream_id not in self.stream_dict:
             raise RuntimeError("Invalid stream id.")
         stream = self.stream_dict[stream_id]
-        # FIXME: This field was removed from the subscription data in Zulip 7.5 / ZFL226
-        #   We should use the new /streams/{stream_id}/email_address endpoint instead
         stream_email = stream.get("email_address", None)
+        if stream_email is None:
+            stream_email = self._fetch_stream_email_from_endpoint(stream_id)
         return stream_email
 
     @staticmethod