feat: switch dynamic MCP container targets

tests/test_stemctl.py

@@ -3,6 +3,7 @@ from __future__ import annotations
 import json
 import io
 import os
+import socket
 import subprocess
 import tempfile
 import unittest
@@ -289,6 +290,50 @@ class StemctlContractTests(unittest.TestCase):
         self.assertEqual(args.mcp_kind, "nvim")
         self.assertEqual(args.instance, "hazard3-inf-bss-task1")
 
+    def test_mcp_select_accepts_instance_or_container_id(self) -> None:
+        parser = rvctl.build_parser()
+        by_instance = parser.parse_args(["mcp", "select", "rp2350-pointers-final"])
+        by_container = parser.parse_args(["mcp", "select", "3aca2c1c4c7a"])
+        self.assertEqual(by_instance.mcp_kind, "select")
+        self.assertEqual(by_instance.selector, "rp2350-pointers-final")
+        self.assertEqual(by_container.selector, "3aca2c1c4c7a")
+
+    def test_mcp_select_switches_both_sockets_with_one_current_symlink(self) -> None:
+        with tempfile.TemporaryDirectory() as temporary:
+            root = Path(temporary)
+            socket_dir = root / "source"
+            socket_dir.mkdir()
+            nvim_server = socket.socket(socket.AF_UNIX)
+            tmux_server = socket.socket(socket.AF_UNIX)
+            try:
+                nvim_server.bind(str(socket_dir / "n.sock"))
+                tmux_server.bind(str(socket_dir / "t.sock"))
+                config = SimpleNamespace(socket_root=root)
+                record = {
+                    "runtime": "podman",
+                    "container_name": "stem-rp2350-example",
+                    "container_id": "3aca2c1c4c7a" + "0" * 52,
+                    "profile": "rp2350",
+                    "target": "rp2350-rv",
+                    "instance": "rp2350-example",
+                    "instance_key": "example000001",
+                    "thread_key": "thread000001",
+                    "socket_dir": str(socket_dir),
+                }
+                with mock.patch.object(rvctl, "resolve_mcp_record", return_value=record), mock.patch.object(
+                    rvctl,
+                    "validated_mcp_record",
+                    return_value=(record, socket_dir / "n.sock", socket_dir / "t.sock"),
+                ), redirect_stdout(io.StringIO()):
+                    rvctl.select_mcp_instance(config, "rp2350-example")
+                current = root / "mcp-selected" / "current"
+                self.assertEqual(os.readlink(current), "targets/3aca2c1c4c7a")
+                self.assertEqual((current / "n.sock").resolve(), socket_dir / "n.sock")
+                self.assertEqual((current / "t.sock").resolve(), socket_dir / "t.sock")
+            finally:
+                nvim_server.close()
+                tmux_server.close()
+
 
 if __name__ == "__main__":
     unittest.main()