# Test Case: DEFLATE Compression Level 9

**Test ID**: TC104-deflate-level9  

**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  
**Regression**: None

## Objective
Verify DEFLATE compressed data path with level 9 (maximum) compression.

## Preconditions
- EROFS image created with DEFLATE level 9: `mkfs.erofs -zdeflate,level=9 test.img src/`
- Large test files (1MB+) for compression testing
- FreeBSD 13.0+ with zlib support

## Test Steps
1. Create image with DEFLATE level 9 compression
2. Attach and mount: `unit=$(mdconfig -a -t vnode -f test.img); mount -t erofs -o ro /dev/${unit} /mnt`
3. Read large compressed files sequentially
4. Test random access throughout file
5. Measure decompression performance

## Expected Results
- All files decompress correctly
- Best compression ratio among DEFLATE levels
- Slightly slower decompression acceptable
- No data corruption

## Verification Method
- Verify checksums match original files
- Compression ratio > level 6
- Decompression throughput > 50 MB/s
- Random access correctness validated

## Cleanup
```sh
umount /mnt
mdconfig -d -u "${unit}"
```

## Notes
Tests feature 58: DEFLATE compressed data path with maximum compression.