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tests/TC077-long-prefix-user-xattr.md

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+# Test Case: Long-prefix user xattr
+
+**Test ID**: TC077-long-prefix-user-xattr
+**Fixture**: `basic.erofs`, `/prefix-user-0`, `/prefix-user-1`
+
+## Objective
+
+Verify reconstruction of a long user name from packed prefix ID 0. The helper
+must self-check prefix record base index 1 and infix
+`repo22.application.component.`.
+
+## Manual steps
+
+```sh
+lsextattr user /mnt/repo22-g4/prefix-user-0
+getextattr -qq -x user repo22.application.component.setting \
+  /mnt/repo22-g4/prefix-user-0
+getextattr -qq -x user repo22.application.component.setting \
+  /mnt/repo22-g4/prefix-user-1
+```
+
+## Expected results
+
+The full name is listed once and the values are `prefix-value-0` and
+`prefix-value-1`. Unmount and detach.