test code v1

tests/TC082-system-namespace-subset.md

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+# Test Case: FreeBSD system namespace subset
+
+**Test ID**: TC082-system-namespace-subset
+**Fixture**: `basic.erofs`, `/acl-unordered`
+
+## Objective
+
+Verify POSIX ACL exposure in FreeBSD namespace `system` and isolation from
+namespace `user`.
+
+## Manual steps
+
+```sh
+lsextattr system /mnt/repo22-g4/acl-unordered
+getextattr -qq -x system posix_acl_access /mnt/repo22-g4/acl-unordered
+getfacl -n /mnt/repo22-g4/acl-unordered
+truss -o /tmp/tc082.truss getextattr -qq user posix_acl_access \
+  /mnt/repo22-g4/acl-unordered
+grep extattr_get_file /tmp/tc082.truss
+```
+
+## Expected results
+
+Raw ACL starts with little-endian version 2; `getfacl` shows named users 3002
+then 2002. The user-namespace request returns `ENOATTR` (87). Clean up.