# Test Case: DEFLATE Level 1 Read Correctness

**Test ID**: TC102-deflate-level1

**G5 fixture contract**: Use [G5-MANUAL-SETUP.md](G5-MANUAL-SETUP.md).
Its generated paths, source comparisons, structured corruption offsets, and
cleanup rules supersede placeholder examples in this file.
**Category**: Compression
**Priority**: High

## Objective

Verify full and offset reads from an erofs-utils 1.8.6 DEFLATE level 1 image.

## Fixture and Helper

```sh
work=$(mktemp -d /tmp/repo22-tc102.XXXXXX)
tests/prepare_error_fixtures.sh "$work/fixtures"
cc -O2 -Wall -Wextra -std=c17 tests/read_probe.c -o "$work/read_probe"
dump.erofs -s "$work/fixtures/valid-deflate-level1.erofs"
dump.erofs --path=/compressed.bin -e \
  "$work/fixtures/valid-deflate-level1.erofs"
```

The superblock and extent output must identify DEFLATE-compressed data. The
image is generated with `-zdeflate,level=1 -C65536`.

## FreeBSD Procedure

```sh
mkdir "$work/mnt"
unit=$(mdconfig -a -t vnode \
  -f "$work/fixtures/valid-deflate-level1.erofs")
mount -t erofs -o ro "/dev/$unit" "$work/mnt"

expected=$(sha256 -q "$work/fixtures/source/compressed.bin")
actual=$(sha256 -q "$work/mnt/compressed.bin")
test "$actual" = "$expected"
"$work/read_probe" pread "$work/mnt/compressed.bin" 32768 4096 \
  "$work/guest-range.bin"
"$work/read_probe" pread "$work/fixtures/source/compressed.bin" 32768 4096 \
  "$work/source-range.bin"
cmp "$work/source-range.bin" "$work/guest-range.bin"

umount "$work/mnt"
mdconfig -d -u "${unit#md}"
```

## Expected Results

The complete mounted-file hash equals the source hash, and the fixed 4 KiB
range compares byte-for-byte. The invalid former command
`sha256 output vs original` is not used.
