fix: get_agent_card tailing slash when A2ACardResolver agent_card_path="" (#799)

Author: mwri

src/a2a/client/card_resolver.py

@@ -74,7 +74,9 @@ async def get_agent_card(
         else:
             path_segment = relative_card_path.lstrip('/')
 
-        target_url = f'{self.base_url}/{path_segment}'
+        target_url = self.base_url
+        if path_segment:
+            target_url = f'{target_url}/{path_segment}'
 
         try:
             response = await self.httpx_client.get(

tests/client/test_card_resolver.py

@@ -213,7 +213,26 @@ async def test_get_agent_card_root_path(
             AgentCard, 'model_validate', return_value=Mock(spec=AgentCard)
         ):
             await resolver.get_agent_card(relative_card_path='/')
-            mock_httpx_client.get.assert_called_once_with(f'{base_url}/')
+            mock_httpx_client.get.assert_called_once_with(f'{base_url}')
+
+    @pytest.mark.asyncio
+    async def test_get_agent_card_with_empty_resolver_agent_card_path(
+        self,
+        base_url,
+        resolver,
+        mock_httpx_client,
+        mock_response,
+        valid_agent_card_data,
+    ):
+        """Test fetching agent card with an empty relative_card_path."""
+        resolver.agent_card_path = ''
+        mock_response.json.return_value = valid_agent_card_data
+        mock_httpx_client.get.return_value = mock_response
+        with patch.object(
+            AgentCard, 'model_validate', return_value=Mock(spec=AgentCard)
+        ):
+            await resolver.get_agent_card()
+            mock_httpx_client.get.assert_called_once_with(f'{base_url}')
 
     @pytest.mark.asyncio
     async def test_get_agent_card_http_status_error(