# Test Case: FLAT_PLAIN Small File

**Test ID**: TC028-flat-plain-small

## Objective

Verify a sub-block regular file explicitly encoded as uncompressed
`FLAT_PLAIN` reads source-exactly.

## Fixture

Use `images/flat.erofs` and `source/flat/small.txt`. Structured evidence asserts
layout 0 and records NID and size.

## Procedure

```sh
stat -f 'size=%z blocks=%b mode=%p' "$mnt/small.txt"
cmp /tmp/repo22-g1/source/flat/small.txt "$mnt/small.txt"
sha256 /tmp/repo22-g1/source/flat/small.txt "$mnt/small.txt"
```

## Expected Results

- Evidence proves `FLAT_PLAIN`; size and data match the source.
- The read, hash, mount, and cleanup all succeed.