# Test Case: Compact Inode I_NLINK_1

**Test ID**: TC021-compact-inode-nlink1

## Objective

Verify bit 4 on a non-directory compact inode forces `st_nlink=1` while the
`i_nb` union remains available for address high bits.

## Fixture

Use `images/compact-nlink1.erofs` and `source/compact/single.txt`.
`fixture-evidence.txt` asserts a 32-byte regular inode, bit 4 set,
`i_nb=0x1234`, and valid recomputed CRC32C.

## Procedure

```sh
stat -f 'ino=%i nlink=%l size=%z mode=%p' "$mnt/single.txt"
cmp /tmp/repo22-g1/source/compact/single.txt "$mnt/single.txt"
sha256 /tmp/repo22-g1/source/compact/single.txt "$mnt/single.txt"
```

## Expected Results

- `st_nlink=1` despite on-disk `i_nb=0x1234`.
- Inline file data remains source-exact; mount and cleanup succeed.
- An `i_nb` value of zero is not used as a substitute for the bit-4 encoding.
