Show MediaWiki API error messages

tests/test_wikidata_api.py

@@ -2,7 +2,13 @@ import pytest
 import pytest_mock
 import requests
 import responses
-from geocode.wikidata import APIResponseError, QueryError, api_call, wdqs
+from geocode.wikidata import (
+    APIResponseError,
+    QueryError,
+    api_call,
+    mediawiki_error_message,
+    wdqs,
+)
 
 max_tries = 5
 
@@ -53,6 +59,39 @@ def test_api_call_retries_on_connection_error(
     assert mocked_sleep.call_count == max_tries - 1
 
 
+@responses.activate
+def test_api_call_uses_mediawiki_error_message(
+    mocker: pytest_mock.plugin.MockerFixture,
+) -> None:
+    """Test MediaWiki API error messages are preserved."""
+    mocker.patch("time.sleep", return_value=None)
+    mocker.patch("geocode.mail.send_to_admin")
+
+    responses.add(
+        responses.GET,
+        "https://www.wikidata.org/w/api.php",
+        json={"error": {"code": "ratelimited", "info": "Too many requests"}},
+        status=429,
+        headers={"Retry-After": "10"},
+    )
+
+    with pytest.raises(APIResponseError) as exc_info:
+        api_call({"action": "wbgetentities", "ids": "Q42"})
+
+    assert exc_info.value.detail == "Too many requests"
+    assert str(exc_info.value) == "Wikidata API error (HTTP 429): Too many requests"
+
+
+def test_mediawiki_error_message_falls_back_to_response_text() -> None:
+    """Test plain-text MediaWiki API errors are preserved."""
+    response = requests.Response()
+    response.status_code = 429
+    response.reason = "Too Many Requests"
+    response._content = b"Please slow down"
+
+    assert mediawiki_error_message(response) == "Please slow down"
+
+
 def test_wdqs_retry(mocker: pytest_mock.plugin.MockerFixture) -> None:
     """Test retry for WDQS API calls."""
     # Patch 'time.sleep' to instantly return, effectively skipping the sleep