feat(cimd): Add additonal tests for CIMD

Author: punitmahes

tests/server/fastmcp/auth/test_auth_integration.py

@@ -1479,6 +1479,40 @@ async def test_cimd_authorization_invalid_client_id(
             assert response.status_code == 400
             assert "client id" in response.text.lower()
 
+    @pytest.mark.anyio
+    async def test_cimd_authorization_metadata_fetch_error(
+        self, test_client: httpx.AsyncClient, pkce_challenge: dict[str, str]
+    ):
+        """Test authorization endpoint when fetching client metadata fails."""
+        client_id_url = "https://example.com/client-metadata"
+
+        # Mocking httpx.AsyncClient to raise an exception
+        mock_client_instance = unittest.mock.AsyncMock(spec=httpx.AsyncClient)
+        mock_client_instance.get.side_effect = httpx.RequestError("Network error")
+
+        # Setup context manager return
+        mock_client_instance.__aenter__.return_value = mock_client_instance
+        mock_client_instance.__aexit__.return_value = None
+
+        with unittest.mock.patch("httpx.AsyncClient", return_value=mock_client_instance):
+            response = await test_client.get(
+                "/authorize",
+                params={
+                    "response_type": "code",
+                    "client_id": client_id_url,
+                    "redirect_uri": "https://client.example.com/callback",
+                    "code_challenge": pkce_challenge["code_challenge"],
+                    "code_challenge_method": "S256",
+                    "state": "cimd_test_state",
+                },
+            )
+
+            # verify that we get a 400 error (because we can't fetch metadata to verify,
+            # and we can't redirect because we don't trust the client yet or don't know its redirect URIs)
+            assert response.status_code == 400
+            assert "invalid_request" in response.text
+            assert "Failed to fetch client metadata" in response.text
+
 
 class TestAuthorizeEndpointErrors:
     """Test error handling in the OAuth authorization endpoint."""