fix: keep Windows bootstrap scripts ASCII-compatible

tests/unit/test_bootstrap_scripts_encoding.py

@@ -0,0 +1,48 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Keep bootstrap scripts ASCII for Windows PowerShell 5.1 compatibility.
+
+BOM-less scripts are decoded using the system ANSI code page. UTF-8 symbols
+can become quote delimiters under cp1252 and cause parse errors.
+"""
+
+from pathlib import Path
+
+import pytest
+
+SCRIPTS_DIR = Path(__file__).resolve().parents[2] / "scripts"
+POWERSHELL_SCRIPTS = sorted(SCRIPTS_DIR.glob("*.ps1"))
+
+
+def test_powershell_scripts_are_discovered():
+    assert POWERSHELL_SCRIPTS, f"no .ps1 scripts found under {SCRIPTS_DIR}"
+
+
+@pytest.mark.parametrize("script", POWERSHELL_SCRIPTS, ids=lambda p: p.name)
+def test_powershell_script_is_pure_ascii(script):
+    raw = script.read_bytes()
+    offending = []
+    line_no = 1
+    for index, byte in enumerate(raw):
+        if byte == 0x0A:
+            line_no += 1
+        elif byte > 0x7F:
+            offending.append((line_no, index, hex(byte)))
+
+    assert not offending, (
+        f"{script.name} contains non-ASCII bytes at (line, offset, byte) "
+        f"{offending[:10]}; Windows PowerShell 5.1 decodes BOM-less .ps1 files "
+        "with the system ANSI code page. Use ASCII status labels."
+    )