Make QA suite test deterministic on headless CI

The pass/fail cases asserted on window state via AC_assert_window, which
is Windows-only and raises NotImplementedError on macOS / Linux CI. The
suite runner scores that as 'error', not pass/fail, so passed/failed
counts and the JUnit failure total were wrong off-Windows. Switch to a
filesystem assertion (AC_assert_file) that is deterministic on every
platform and raises a proper AutoControlAssertionException on mismatch.

Author: JE-Chen

test/unit_test/headless/test_test_suite.py

@@ -10,8 +10,14 @@
     write_allure_results, write_junit_xml,
 )
 
-_PASS = ["AC_assert_window", {"title": "zzz_no_window", "exists": False}]
-_FAIL = ["AC_assert_window", {"title": "zzz_no_window", "exists": True}]
+# Use a filesystem assertion so the pass/fail outcome is deterministic on
+# every platform. ``AC_assert_window`` is Windows-only (it raises
+# NotImplementedError on macOS / Linux CI, which the suite runner scores as
+# *error* rather than pass/fail); ``AC_assert_file`` only touches the
+# filesystem and raises ``AutoControlAssertionException`` on mismatch.
+_MISSING_FILE = "zzz_no_such_dir_qa/zzz_no_such_file.tmp"
+_PASS = ["AC_assert_file", {"path": _MISSING_FILE, "exists": False}]
+_FAIL = ["AC_assert_file", {"path": _MISSING_FILE, "exists": True}]
 
 
 def _spec():