Python A2A: Expose supported_protocol_bindings as configurable parameter (#6098)

* Expose supported_protocol_bindings as configurable parameter on A2AAgent Add supported_protocol_bindings parameter to A2AAgent.__init__() allowing users to configure which A2A protocol bindings (JSONRPC, GRPC, HTTP+JSON) the client prefers when connecting to remote agents. - Defaults to ["JSONRPC"] matching current behavior - Passes through to ClientConfig for transport negotiation - Replaces 4 hardcoded references with the configurable value Closes #6057 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> * Fix empty list falsy trap and add fallback path test coverage - Use 'is not None' check instead of 'or' to preserve explicit empty list - Add test verifying empty list is not silently replaced with defaults - Add test verifying fallback path uses custom bindings Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> * Document known protocol binding values in docstring Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> * Use Literal union for protocol binding type hint Provides IDE autocomplete for known values while keeping the type open for custom bindings (Literal is str at runtime). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> --------- Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-06-16 21:04:09 +08:00 · 2026-05-28 12:05:13 -07:00
parent d2f79930d5
commit e9a606344a
2 changed files with 97 additions and 5 deletions
@@ -703,7 +703,94 @@ def test_a2a_agent_initialization_with_timeout_parameter() -> None:
        assert isinstance(timeout_arg, httpx.Timeout)


-# region Continuation Token Tests
+def test_a2a_agent_initialization_with_supported_protocol_bindings() -> None:
+    """Test A2AAgent initialization with custom supported_protocol_bindings."""
+    with (
+        patch("agent_framework_a2a._agent.httpx.AsyncClient") as mock_async_client,
+        patch("agent_framework_a2a._agent.ClientConfig") as mock_config,
+        patch("agent_framework_a2a._agent.ClientFactory") as mock_factory,
+    ):
+        mock_async_client.return_value = MagicMock()
+        mock_client_instance = MagicMock()
+        mock_factory.return_value.create.return_value = mock_client_instance
+
+        A2AAgent(
+            name="Test Agent",
+            url="https://test-agent.example.com",
+            supported_protocol_bindings=["GRPC", "JSONRPC"],
+        )
+
+        # Verify ClientConfig was called with our custom bindings for both streaming and non-streaming
+        assert mock_config.call_count == 2
+        for call in mock_config.call_args_list:
+            assert call.kwargs["supported_protocol_bindings"] == ["GRPC", "JSONRPC"]
+
+
+def test_a2a_agent_initialization_defaults_to_jsonrpc() -> None:
+    """Test A2AAgent defaults to JSONRPC when supported_protocol_bindings is not provided."""
+    with (
+        patch("agent_framework_a2a._agent.httpx.AsyncClient") as mock_async_client,
+        patch("agent_framework_a2a._agent.ClientConfig") as mock_config,
+        patch("agent_framework_a2a._agent.ClientFactory") as mock_factory,
+    ):
+        mock_async_client.return_value = MagicMock()
+        mock_client_instance = MagicMock()
+        mock_factory.return_value.create.return_value = mock_client_instance
+
+        A2AAgent(name="Test Agent", url="https://test-agent.example.com")
+
+        # Verify ClientConfig was called with default JSONRPC bindings
+        assert mock_config.call_count == 2
+        for call in mock_config.call_args_list:
+            assert call.kwargs["supported_protocol_bindings"] == ["JSONRPC"]
+
+
+def test_a2a_agent_initialization_empty_list_preserved() -> None:
+    """Test that an explicit empty list is preserved and not replaced with defaults."""
+    with (
+        patch("agent_framework_a2a._agent.httpx.AsyncClient") as mock_async_client,
+        patch("agent_framework_a2a._agent.ClientConfig") as mock_config,
+        patch("agent_framework_a2a._agent.ClientFactory") as mock_factory,
+    ):
+        mock_async_client.return_value = MagicMock()
+        mock_client_instance = MagicMock()
+        mock_factory.return_value.create.return_value = mock_client_instance
+
+        A2AAgent(
+            name="Test Agent",
+            url="https://test-agent.example.com",
+            supported_protocol_bindings=[],
+        )
+
+        # Verify ClientConfig was called with the explicit empty list, not the default
+        assert mock_config.call_count == 2
+        for call in mock_config.call_args_list:
+            assert call.kwargs["supported_protocol_bindings"] == []
+
+
+def test_a2a_agent_fallback_uses_custom_bindings() -> None:
+    """Test that transport fallback path uses custom bindings."""
+    mock_agent_card = MagicMock()
+    mock_agent_card.supported_interfaces = [MagicMock(url="https://fallback.example.com")]
+
+    mock_factory = MagicMock()
+    # First create() call fails (primary streaming), then fallback calls succeed
+    primary_error = Exception("no compatible transports found")
+    mock_factory.create.side_effect = [primary_error, MagicMock(), MagicMock()]
+
+    with (
+        patch("agent_framework_a2a._agent.ClientFactory", return_value=mock_factory),
+        patch("agent_framework_a2a._agent.minimal_agent_card") as mock_minimal_card,
+        patch("agent_framework_a2a._agent.httpx.AsyncClient"),
+    ):
+        A2AAgent(
+            name="test-agent",
+            agent_card=mock_agent_card,
+            supported_protocol_bindings=["GRPC", "HTTP+JSON"],
+        )
+
+        # Verify minimal_agent_card was called with the custom bindings
+        mock_minimal_card.assert_called_once_with("https://fallback.example.com", ["GRPC", "HTTP+JSON"])


 async def test_working_task_emits_continuation_token(a2a_agent: A2AAgent, mock_a2a_client: MockA2AClient) -> None: