Use the frozen helper in both CLI budget probe checkouts

examples/control_plane/cli-output-probe-runner.py

@@ -459,11 +459,13 @@ def main() -> int:
     )
     args = parser.parse_args()
     _install_pytest_import_stub()
-    probe = _load_module("loopx_cli_output_probe_fixture", args.test_source)
+    # Bind the frozen workload's helpers before it imports them. LoopX itself
+    # still comes from the product checkout selected for this subprocess.
     fixture_support = _load_module(
-        "loopx_cli_output_fixture_support",
+        "tests.control_plane.cli_output_fixture",
         Path(__file__).with_name("cli_output_fixture.py"),
     )
+    probe = _load_module("loopx_cli_output_probe_fixture", args.test_source)
     # Scenario helpers also call this owner; historical test modules must not
     # re-enter their old /tmp implementation from inside the shared outer root.
     probe._stable_budget_fixture_root = fixture_support.stable_budget_fixture_root

tests/control_plane/test_cli_output_probe_runner.py

@@ -1,9 +1,12 @@
 from __future__ import annotations
 
 import json
+import os
 import runpy
 import re
 import shlex
+import shutil
+import subprocess
 import sys
 from pathlib import Path
 from types import SimpleNamespace
@@ -21,6 +24,52 @@
 )
 
 
+def test_runner_imports_frozen_support_with_an_older_checkout(tmp_path: Path) -> None:
+    workload = tmp_path / "workload"
+    workload.mkdir()
+    runner = workload / RUNNER.name
+    shutil.copyfile(RUNNER, runner)
+    shutil.copyfile(cli_output_fixture.__file__, workload / "cli_output_fixture.py")
+
+    historical = tmp_path / "historical"
+    legacy_tests = historical / "tests" / "control_plane"
+    legacy_tests.mkdir(parents=True)
+    for package in (legacy_tests, legacy_tests.parent):
+        (package / "__init__.py").touch()
+    (legacy_tests / "cli_output_fixture.py").write_text(
+        "# Older checkout with no current observation helper.\n", encoding="utf-8"
+    )
+    probe_source = workload / "probe.py"
+    probe_source.write_text(
+        "from pathlib import Path\n"
+        "from tests.control_plane.cli_output_fixture import measure_cli_context_for_oracle\n"
+        "assert Path(measure_cli_context_for_oracle.__code__.co_filename) == "
+        "Path(__file__).with_name('cli_output_fixture.py')\n"
+        "print('frozen fixture support loaded')\n"
+        "raise SystemExit(0)\n",
+        encoding="utf-8",
+    )
+
+    result = subprocess.run(
+        [
+            sys.executable, str(runner),
+            "--test-source", str(probe_source),
+            "--semantics-source", str(workload / "unused_semantics.py"),
+            "--fixture-root", str(workload / "unused_fixture"),
+            "--receipt", str(workload / "unused_receipt.json"),
+        ],
+        cwd=workload,
+        env={
+            **os.environ,
+            "PYTHONPATH": os.pathsep.join((str(historical), str(RUNNER.parents[2]))),
+            "LOOPX_USAGE_PING": "0",
+        },
+        capture_output=True, text=True, encoding="utf-8", timeout=30, check=False,
+    )
+    assert result.returncode == 0, result.stderr
+    assert result.stdout.strip() == "frozen fixture support loaded"
+
+
 @pytest.fixture
 def crowded_turn_probe(monkeypatch: pytest.MonkeyPatch):
     commands = probe._surface_commands