chore: import upstream snapshot with attribution

tests/docs_src/test_session_groups.py

@@ -0,0 +1,98 @@
+"""`docs/client/session-groups.md`: every claim the page makes, proved against the real SDK.
+
+`connect_to_server` opens a real transport (a subprocess or a socket), so these tests drive the
+exact same aggregation path through `connect_with_session` with in-memory sessions instead.
+"""
+
+import traceback
+
+import pytest
+from mcp_types import INVALID_PARAMS, Implementation
+
+from docs_src.session_groups import tutorial001, tutorial002, tutorial004
+from mcp import Client, ClientSessionGroup, MCPError
+
+# See test_index.py for why this is a per-module mark and not a conftest hook.
+pytestmark = [pytest.mark.anyio, pytest.mark.filterwarnings("error::mcp.MCPDeprecationWarning")]
+
+
+async def test_both_servers_call_their_tool_search() -> None:
+    """tutorial001 + tutorial002: two unrelated servers, one colliding tool name."""
+    async with Client(tutorial001.mcp) as library, Client(tutorial002.mcp) as web:
+        (library_tool,) = (await library.list_tools()).tools
+        (web_tool,) = (await web.list_tools()).tools
+        assert library_tool.name == "search"
+        assert web_tool.name == "search"
+
+
+async def test_a_connected_server_is_aggregated_into_the_group() -> None:
+    """tutorial003: the group exposes every component of every connected server as a dict."""
+    async with Client(tutorial001.mcp) as library:
+        group = ClientSessionGroup()
+        await group.connect_with_session(library.server_info, library.session)
+        assert sorted(group.tools) == ["search"]
+        assert sorted(group.resources) == ["hours"]
+        assert group.prompts == {}
+        assert group.tools["search"].description == "Search the library catalog."
+
+
+async def test_colliding_names_are_rejected() -> None:
+    """tutorial003: without a hook the second `search` raises, and nothing from `Web` is kept."""
+    async with Client(tutorial001.mcp) as library, Client(tutorial002.mcp) as web:
+        group = ClientSessionGroup()
+        await group.connect_with_session(library.server_info, library.session)
+        with pytest.raises(MCPError) as exc_info:
+            await group.connect_with_session(web.server_info, web.session)
+        assert str(exc_info.value) == "{'search'} already exist in group tools."
+        assert exc_info.value.error.code == INVALID_PARAMS
+        assert sorted(group.tools) == ["search"]
+        # The page's `!!! check` fence is the last line of the traceback, verbatim.
+        assert traceback.format_exception_only(exc_info.value) == [
+            "mcp.shared.exceptions.MCPError: {'search'} already exist in group tools.\n"
+        ]
+
+
+async def test_component_name_hook_prefixes_every_name() -> None:
+    """tutorial004: the hook rewrites every registered name, so both servers coexist."""
+    async with Client(tutorial001.mcp) as library, Client(tutorial002.mcp) as web:
+        group = ClientSessionGroup(component_name_hook=tutorial004.by_server)
+        await group.connect_with_session(library.server_info, library.session)
+        await group.connect_with_session(web.server_info, web.session)
+        assert sorted(group.tools) == ["Library.search", "Web.search"]
+        assert sorted(group.resources) == ["Library.hours"]
+
+
+def test_the_hook_is_a_plain_function_of_name_and_server_info() -> None:
+    """tutorial004: `by_server` builds the key from `server_info.name`."""
+    assert tutorial004.by_server("search", Implementation(name="Web", version="1.0.0")) == "Web.search"
+
+
+async def test_the_key_is_prefixed_but_the_wire_name_is_not() -> None:
+    """tutorial004: the dict key is yours; the `Tool` inside keeps the name the server declared."""
+    async with Client(tutorial002.mcp) as web:
+        group = ClientSessionGroup(component_name_hook=tutorial004.by_server)
+        await group.connect_with_session(web.server_info, web.session)
+        assert group.tools["Web.search"].name == "search"
+
+
+async def test_call_tool_routes_to_the_owning_server() -> None:
+    """tutorial004: `group.call_tool` resolves the prefixed name to the session that owns it."""
+    async with Client(tutorial001.mcp) as library, Client(tutorial002.mcp) as web:
+        group = ClientSessionGroup(component_name_hook=tutorial004.by_server)
+        await group.connect_with_session(library.server_info, library.session)
+        await group.connect_with_session(web.server_info, web.session)
+        web_result = await group.call_tool("Web.search", {"query": "model context protocol"})
+        assert web_result.structured_content == {"result": "12 pages match 'model context protocol'."}
+        library_result = await group.call_tool("Library.search", {"query": "dune"})
+        assert library_result.structured_content == {"result": "3 books match 'dune'."}
+
+
+async def test_disconnect_removes_every_component_of_that_server() -> None:
+    """tutorial004: `disconnect_from_server` takes the session back out of all three dicts."""
+    async with Client(tutorial001.mcp) as library, Client(tutorial002.mcp) as web:
+        group = ClientSessionGroup(component_name_hook=tutorial004.by_server)
+        await group.connect_with_session(library.server_info, library.session)
+        web_session = await group.connect_with_session(web.server_info, web.session)
+        await group.disconnect_from_server(web_session)
+        assert sorted(group.tools) == ["Library.search"]
+        assert sorted(group.resources) == ["Library.hours"]