test(issue-20): record and drop the ambient control-plane binding before collection; per-test default registry and audit-log roots

pytest_configure records WORKSPACE_ROOT, AGENT_SESSIONS_YAML, MAM_JOBS_DIR and DELEGATE_JOB_LOGS_DIR and drops the last three, plus WORKSPACE_ROOT when it names another checkout: a worktree creator's pane carries all four at the live main checkout, and each wins over a test's own WORKSPACE_ROOT. It runs before collection because test_orc_onboard copies os.environ at import. Every test then defaults MAM_JOBS_DIR and DELEGATE_JOB_LOGS_DIR to tmp_path/.mam-test-state; mam_sandbox and a test's own monkeypatch still override.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Sdga4A8i1iSc8DaaW9iKU2

tests/conftest.py

@@ -109,6 +109,65 @@ def _pid_alive(pid):
     return bool(state) and not state.startswith("Z")
 
 
+# ==============================================================================
+# Issue #20: test state stays out of every real control plane.
+#
+# An agent pane can carry a control-plane binding: a worktree creator's pane
+# gets WORKSPACE_ROOT, AGENT_SESSIONS_YAML, MAM_JOBS_DIR and
+# DELEGATE_JOB_LOGS_DIR pointing at the live main checkout (create/resume
+# forward the row's control_plane), and each of them wins over a test's own
+# WORKSPACE_ROOT (mqtt_common.default_registry_dir/get_logs_dir, lib.sh's
+# AGENT_SESSIONS_YAML). pytest_configure records the binding and drops it
+# before collection - a session fixture is too late for a module that copies
+# os.environ at import (test_orc_onboard.SCRUBBED_ENV). WORKSPACE_ROOT is
+# dropped only when it names another checkout; naming this one, it is what
+# lib.sh derives anyway. Every test then defaults to a registry and an
+# audit-log root under its own tmp_path, and a session guard (next to the #19
+# one) reports new entries in the recorded control planes.
+# ==============================================================================
+_REPO_ROOT = Path(__file__).resolve().parent.parent
+
+_BINDING_VARS = ("WORKSPACE_ROOT", "AGENT_SESSIONS_YAML", "MAM_JOBS_DIR", "DELEGATE_JOB_LOGS_DIR")
+_RECORDED_BINDING = {}
+_DROPPED_BINDING = pytest.StashKey[dict]()
+
+
+def pytest_configure(config):
+    _RECORDED_BINDING.clear()
+    _RECORDED_BINDING.update({k: os.environ[k] for k in _BINDING_VARS if os.environ.get(k)})
+    dropped = {k: os.environ.pop(k) for k in ("AGENT_SESSIONS_YAML", "MAM_JOBS_DIR", "DELEGATE_JOB_LOGS_DIR")
+               if k in os.environ}
+    ws = os.environ.get("WORKSPACE_ROOT")
+    if ws and os.path.realpath(ws) != str(_REPO_ROOT):
+        dropped["WORKSPACE_ROOT"] = os.environ.pop("WORKSPACE_ROOT")
+    config.stash[_DROPPED_BINDING] = dropped
+
+
+def pytest_unconfigure(config):
+    # Back for callers that run pytest.main() in-process.
+    os.environ.update(config.stash.get(_DROPPED_BINDING, {}))
+
+
+@pytest.fixture(scope="session")
+def _ambient_control_plane():
+    """The binding pytest_configure recorded (and dropped), as a copy."""
+    return dict(_RECORDED_BINDING)
+
+
+@pytest.fixture(autouse=True)
+def _isolate_mam_state_dirs(_ambient_control_plane, tmp_path, monkeypatch):
+    """Default registry and audit-log roots under this test's tmp_path; only
+    the env is set, nothing is created. mam_sandbox and a test's own
+    setenv/delenv run after this autouse fixture and win, and the shared
+    function-scope monkeypatch undoes them in LIFO order. A hidden directory,
+    so tests that use tmp_path/"jobs" as their own registry or list tmp_path
+    are unaffected. Takes _ambient_control_plane to state the order, not to
+    rely on it."""
+    state = tmp_path / ".mam-test-state"
+    monkeypatch.setenv("MAM_JOBS_DIR", str(state / "jobs"))
+    monkeypatch.setenv("DELEGATE_JOB_LOGS_DIR", str(state / "delegate_job_logs"))
+
+
 @pytest.fixture
 def mam_sandbox(tmp_path, monkeypatch, request):
     """