# Test Case: Tailpacking Block Boundaries

**Test ID**: TC034-tailpacking-boundary

## Objective

Verify the actual erofs-utils boundary choices at 4095, 4096, and 4097 bytes,
including the one-byte inline tail case.

## Fixture

Use `images/inline.erofs` and the three matching files under `source/inline`.
Structured evidence requires layouts `0,0,2` respectively. A 4095-byte payload
cannot fit beside a 32-byte inode in one 4096-byte metadata block, so it is not
claimed as fully inline.

## Procedure

```sh
for size in 4095 4096 4097; do
  stat -f '%N size=%z blocks=%b' "$mnt/file-$size.dat"
  cmp "/tmp/repo22-g1/source/inline/file-$size.dat" "$mnt/file-$size.dat"
  sha256 "/tmp/repo22-g1/source/inline/file-$size.dat" "$mnt/file-$size.dat"
done
./read_probe pread "$mnt/file-4097.dat" 4088 9 /tmp/tc034-boundary
dd if=/tmp/repo22-g1/source/inline/file-4097.dat \
  of=/tmp/tc034-source bs=1 skip=4088 count=9 2>/dev/null
cmp /tmp/tc034-source /tmp/tc034-boundary
```

## Expected Results

- Exact sizes and full hashes match for all three files.
- 4095 and 4096 are FLAT_PLAIN; 4097 is FLAT_INLINE with a one-byte tail.
- The nine-byte cross-boundary range matches; cleanup succeeds.