enhancement: support Windows testing and terminal behavior

CHANGELOG.md

@@ -10,6 +10,8 @@ and versions are tracked in the repo-root `VERSION` file.
 - Keep private runtime files and directories owner-only on POSIX, use inherited
   user-profile ACLs on Windows, and make history appends binary-safe across
   locking backends.
+- Make terminal detection tolerate closed streams and record `COMSPEC` when
+  Windows has no `SHELL` environment variable.
 
 ## [0.2.0] - 2026-08-01
 

README.md

@@ -499,8 +499,9 @@ def test_command(tmp_path: Path) -> None:
     assert "hello Ada" in result.stdout
 ```
 
-The helper wraps Click's `CliRunner`, sets `HOME` when requested, and supplies
-`cwd` to the invocation for the duration of the test. Calls that use
+The helper wraps Click's `CliRunner`, sets `HOME` plus the relevant
+`USERPROFILE`, `LOCALAPPDATA`, and `XDG_CACHE_HOME` values when requested, and
+supplies `cwd` to the invocation for the duration of the test. Calls that use
 `cwd` are serialized and the caller's cwd is restored afterward, but this
 remains process-global: do not use it concurrently with code that changes cwd
 outside `invoke()` or from threads spawned by the invoked command. A

lib/python/base_cli/history.py

@@ -84,7 +84,7 @@ def build_finished_record(
         "project_root": compact_optional_path(context.project_root),
         "manifest": compact_optional_path(context.manifest_path),
         "workspace_root": compact_optional_path(context.workspace_root),
-        "shell": os.environ.get("SHELL"),
+        "shell": current_shell(),
         "scope": context.history_scope,
         "parent_run_id": context.history_parent_run_id,
     }
@@ -286,6 +286,12 @@ def normalized_os() -> str:
     return system or platform.platform()
 
 
+def current_shell() -> str | None:
+    """Return the active shell identifier across POSIX and Windows."""
+
+    return os.environ.get("SHELL") or os.environ.get("COMSPEC")
+
+
 def redact_history_argv(argv: list[str], sensitive_options: set[str]) -> list[str]:
     redacted = redact_argv(argv, sensitive_options)
     result: list[str] = []

lib/python/base_cli/logging.py

@@ -69,12 +69,12 @@ def _handler_formatter(formatter: logging.Formatter | None, *, use_color: bool)
 
 
 def _use_color(stream: TextIO) -> bool:
-    return (
-        os.environ.get("BASE_CLI_COLOR") != "0"
-        and "NO_COLOR" not in os.environ
-        and hasattr(stream, "isatty")
-        and stream.isatty()
-    )
+    if os.environ.get("BASE_CLI_COLOR") == "0" or "NO_COLOR" in os.environ:
+        return False
+    try:
+        return bool(stream.isatty())
+    except (AttributeError, OSError, ValueError):
+        return False
 
 
 def secure_log_file_permissions(log_file: Path) -> None:

lib/python/base_cli/output.py

@@ -30,7 +30,7 @@ def is_terminal(stream: TextIO | None = None) -> bool:
     candidate = stream if stream is not None else sys.stdout
     try:
         return bool(candidate.isatty())
-    except (AttributeError, OSError):
+    except (AttributeError, OSError, ValueError):
         return False
 
 

tests/test_history.py

@@ -22,6 +22,18 @@ def locking(self, _fd: int, mode: int, size: int) -> None:
 
 
 class HistoryAppendTests(unittest.TestCase):
+    def test_current_shell_falls_back_to_comspec(self) -> None:
+        with mock.patch.dict("os.environ", {"COMSPEC": r"C:\Windows\System32\cmd.exe"}, clear=True):
+            self.assertEqual(history.current_shell(), r"C:\Windows\System32\cmd.exe")
+
+    def test_current_shell_prefers_shell(self) -> None:
+        with mock.patch.dict(
+            "os.environ",
+            {"SHELL": "/bin/zsh", "COMSPEC": r"C:\Windows\System32\cmd.exe"},
+            clear=True,
+        ):
+            self.assertEqual(history.current_shell(), "/bin/zsh")
+
     def test_concurrent_appends_produce_complete_records(self) -> None:
         with tempfile.TemporaryDirectory() as tmpdir:
             path = Path(tmpdir) / "history.jsonl"

tests/test_logging.py

@@ -105,6 +105,20 @@ def test_configure_logger_honors_explicit_color_disable(self) -> None:
 
         self.assertNotIn("\033[", stream.getvalue())
 
+    def test_configure_logger_handles_streams_that_reject_isatty(self) -> None:
+        class ClosedStream(io.StringIO):
+            def isatty(self) -> bool:
+                raise ValueError("stream is closed")
+
+        stream = ClosedStream()
+
+        with mock.patch.dict(os.environ, {}, clear=True):
+            logger = base_cli.configure_logger("closed-stream", None, debug=False, stream=stream)
+            logger.info("hello closed stream")
+
+        self.assertNotIn("\033[", stream.getvalue())
+        self.assertIn("hello closed stream", stream.getvalue())
+
     def test_configure_logger_uses_custom_formatter_for_file_handler(self) -> None:
         formatter = logging.Formatter("%(levelname)s:%(message)s")
         user_stream = io.StringIO()

tests/test_output.py

@@ -18,6 +18,11 @@ def isatty(self) -> bool:
         return self.terminal
 
 
+class _ClosedStream(io.StringIO):
+    def isatty(self) -> bool:
+        raise ValueError("stream is closed")
+
+
 RECORDS = (
     {"name": "base", "path": "/work/base"},
     {"name": "demo,one", "path": "/work/demo\tone"},
@@ -26,6 +31,9 @@ def isatty(self) -> bool:
 
 
 class OutputTest(unittest.TestCase):
+    def test_closed_stream_is_not_treated_as_terminal(self) -> None:
+        self.assertEqual(resolve_output_format("text", stream=_ClosedStream()), "tsv")
+
     def test_text_is_pretty_on_terminal(self) -> None:
         stream = _Stream(terminal=True)