# Test Case: FLAT_PLAIN Medium File

**Test ID**: TC029-flat-plain-medium

## Objective

Verify complete and nonzero-offset reads of a multi-block `FLAT_PLAIN` file.

## Fixture

Use `images/flat.erofs`, `source/flat/medium.dat`, and
`expected/medium-10-5.bin`. Evidence asserts layout 0 and size 102417.

## Procedure

```sh
stat -f 'size=%z blocks=%b' "$mnt/medium.dat"
cmp /tmp/repo22-g1/source/flat/medium.dat "$mnt/medium.dat"
./read_probe pread "$mnt/medium.dat" 40960 20480 /tmp/tc029-range
cmp /tmp/repo22-g1/expected/medium-10-5.bin /tmp/tc029-range
sha256 /tmp/repo22-g1/source/flat/medium.dat "$mnt/medium.dat" \
  /tmp/repo22-g1/expected/medium-10-5.bin /tmp/tc029-range
```

Remove the range output, unmount, and detach.

## Expected Results

- Full file and the five-block range match their deterministic sources.
- No block-boundary truncation or cleanup failure occurs.
