---
phase: 05-shell-decoder
plan: 02
subsystem: shell-decoder
tags: [posix-sh, cross-validation, sha256, test-script, busybox, cyrillic]

# Dependency graph
requires:
  - phase: 05-shell-decoder
    plan: 01
    provides: "shell/decode.sh -- busybox-compatible POSIX shell decoder"
  - phase: 02-core-archiver
    provides: "Rust archiver CLI for creating test archives"
provides:
  - "shell/test_decoder.sh -- cross-validation test script (6 tests, Rust pack -> Shell decode -> SHA-256 verify)"
  - "Validated shell decoder correctness across all edge cases: text, binary, no-compress, empty, large, Cyrillic filenames"
affects: [06-obfuscation]

# Tech tracking
tech-stack:
  added: [bash-test-framework]
  patterns: [cross-validation-testing, rust-pack-shell-decode-sha256-verify]

key-files:
  created:
    - shell/test_decoder.sh

key-decisions:
  - "All 6 tests passed on first run -- no decode.sh fixes needed"
  - "Used sh (not bash) to invoke decode.sh in tests for POSIX compatibility validation"
  - "Followed kotlin/test_decoder.sh pattern for consistency across decoder test suites"

patterns-established:
  - "Cross-validation test pattern: Rust pack -> decoder unpack -> SHA-256 comparison (reusable for any decoder)"
  - "Test script structure: prerequisites -> build -> test cases -> summary with pass/fail counts"

requirements-completed: [SHL-01, SHL-02, SHL-03]

# Metrics
duration: 2min
completed: 2026-02-25
---

# Phase 5 Plan 2: Shell Decoder Cross-Validation Tests Summary

**Cross-validation test script with 6 test cases (single file, multiple files, no-compress, empty, large 100KB, Cyrillic filename) all passing on first run via Rust pack -> sh decode.sh -> SHA-256 verify**

## Performance

- **Duration:** 2 min
- **Started:** 2026-02-24T22:42:47Z
- **Completed:** 2026-02-24T22:44:38Z
- **Tasks:** 2
- **Files created:** 1

## Accomplishments
- Created comprehensive cross-validation test script (275 lines) following kotlin/test_decoder.sh pattern
- All 6 test cases passed on first run with zero decode.sh fixes needed
- Validated SHL-01 (single text file), SHL-02 (no-compress mode), and SHL-03 (Cyrillic UTF-8 filename)
- Verified shell decoder produces byte-identical output to originals via SHA-256 comparison
- Confirmed existing Rust test suite (6 tests) still passes -- no regressions

## Task Commits

Each task was committed atomically:

1. **Task 1: Create shell/test_decoder.sh cross-validation test script** - `e9d7442` (test)
2. **Task 2: Run cross-validation tests and fix any decode.sh issues** - no commit (all tests passed, no fixes needed)

## Files Created/Modified
- `shell/test_decoder.sh` - Cross-validation test script: 6 test cases covering all edge cases for shell decoder

## Decisions Made
- All 6 tests passed on first run -- decode.sh implementation from Plan 1 was correct
- Used `sh "$DECODER"` (not `bash`) to invoke decode.sh, ensuring POSIX sh compatibility is tested
- Followed kotlin/test_decoder.sh pattern exactly for consistency across decoder test suites
- 7 total assertions across 6 tests (Test 2 verifies both text.txt and binary.bin)

## Deviations from Plan

None - plan executed exactly as written.

## Issues Encountered
None.

## User Setup Required
None - no external service configuration required.

## Next Phase Readiness
- Shell decoder fully validated with cross-validation tests
- Phase 5 (Shell Decoder) is complete: both decode script and test suite done
- Phase 6 (Obfuscation) can extend decode.sh with XOR header deobfuscation and encrypted TOC parsing
- Test script can serve as regression test when obfuscation layer is added

---

## Self-Check: PASSED

- FOUND: shell/test_decoder.sh
- FOUND: commit e9d7442
- FOUND: 05-02-SUMMARY.md

---
*Phase: 05-shell-decoder*
*Completed: 2026-02-25*