emrg: the fixture home is pinned in both spellings, so the suite stops writing into the host root

tests/test_bash_tool_sandbox.py

@@ -11,6 +11,7 @@
 import subprocess
 import sys
 import tempfile
+from pathlib import Path
 
 import pytest
 
@@ -734,10 +735,18 @@ def test_workspace_write_allows_evolution_memory(monkeypatch, tmp_path):
     module's own data root) even though it is outside the repo workspace."""
     import emrg.tools.bash_tool as bt
     # Pin the user home + evolution data root so the test is hermetic and does
-    # not depend on this host's real ~/.emrg layout.
+    # not depend on this host's real ~/.emrg layout. Pin both spellings:
+    # expanduser reads USERPROFILE on Windows and HOME elsewhere, so HOME alone
+    # left the path resolving to the reading host's real root — a pure predicate
+    # here, a real write in tests/test_write_tool.py's sibling test.
     monkeypatch.setenv("HOME", str(tmp_path / "home"))
-    # Recompute the trusted zone against the pinned HOME.
+    monkeypatch.setenv("USERPROFILE", str(tmp_path / "home"))
+    # Recompute the trusted zone against the pinned home.
     evo_data = os.path.realpath(os.path.expanduser("~/.emrg/evolution/.emrg"))
+    assert Path(evo_data).is_relative_to(Path(os.path.realpath(str(tmp_path)))), (
+        "the fixture home did not take: this test would measure the reading "
+        f"host's real data root ({evo_data})"
+    )
     ws = str(tmp_path / "ws")
     # check_workspace_write (write/edit tools)
     meta = evo_data + "/memory/cycle-20260901-000000.md"
@@ -754,7 +763,12 @@ def test_workspace_write_allows_evolution_session_scratch(monkeypatch, tmp_path)
     per the _trusted_write_zones() docstring — lock it in so a future narrowing
     of the zone to memory/ alone cannot silently break session writes."""
     monkeypatch.setenv("HOME", str(tmp_path / "home"))
+    monkeypatch.setenv("USERPROFILE", str(tmp_path / "home"))
     evo_data = os.path.realpath(os.path.expanduser("~/.emrg/evolution/.emrg"))
+    assert Path(evo_data).is_relative_to(Path(os.path.realpath(str(tmp_path)))), (
+        "the fixture home did not take: this test would measure the reading "
+        f"host's real data root ({evo_data})"
+    )
     ws = str(tmp_path / "ws")
     # check_workspace_write (write/edit tools)
     session = evo_data + "/sessions/emrg-evolution-emrg-task/history.jsonl"

tests/test_write_tool.py

@@ -225,10 +225,26 @@ def test_write_workspace_write_allows_evolution_memory(tmp_path, monkeypatch):
     """Issue #1093 self-regression: the evolution module writes its cycle records
     to ~/.emrg/evolution/.emrg/memory/, which is OUTSIDE the repo checkout
     workspace. The workspace-write boundary must trust that data root so the
-    evolution module can still record its own history (positive state)."""
+    evolution module can still record its own history (positive state).
+
+    Both spellings of the home are pinned, because ``os.path.expanduser("~")``
+    reads ``USERPROFILE`` on Windows and ``HOME`` elsewhere: with only ``HOME``
+    set the resolved root stayed this host's real one, so this test — the one of
+    the three that *executes* the write instead of handing the path to a pure
+    predicate — wrote a fixture file into the host's
+    ``~/.emrg/evolution/.emrg/memory/`` on every suite run. Measured
+    2026-09-28: it was the single file under that 230-file root whose mtime
+    moved. The assertion below makes the fixture home a premise the test checks
+    rather than one it assumes.
+    """
     import os
     monkeypatch.setenv("HOME", str(tmp_path / "home"))
+    monkeypatch.setenv("USERPROFILE", str(tmp_path / "home"))
     evo_data = Path(os.path.realpath(os.path.expanduser("~/.emrg/evolution/.emrg")))
+    assert evo_data.is_relative_to(Path(os.path.realpath(str(tmp_path)))), (
+        "the fixture home did not take: this test would write into the reading "
+        f"host's real data root ({evo_data})"
+    )
     evo_data.mkdir(parents=True, exist_ok=True)
     ws = tmp_path / "ws"
     ws.mkdir()