Testing

Running Tests

cd src/cosh-ng

# All tests
cargo test --locked

# By crate
cargo test --locked -p cosh-types      # Pure types, no tests
cargo test --locked -p cosh-platform   # 174 unit tests
cargo test --locked -p cosh-cli        # 55 integration tests
cargo test --locked -p cosh-core       # Unit + integration tests
cargo test --locked -p cosh-shell      # Unit + integration (includes PTY tests, slower)

# Run a single test
cargo test --locked -p cosh-platform test_detect_alinux

# Run a specific test file
cargo test --locked -p cosh-cli --test cli_integration

Test Layers

cosh-types

Pure type definitions, typically no tests. Serialization/deserialization correctness is covered by upper-layer crate tests.

cosh-platform

Unit tests cover:

• Distribution detection (mocking /etc/os-release)
• Package manager command generation
• Audit policy rule matching
• ws-ckpt IPC protocol encoding/decoding

cargo test --locked -p cosh-platform
# ~174 tests, < 1s

cosh-cli

Integration tests (crates/cosh-cli/tests/cli_integration.rs):

• JSON output envelope format validation
• --dry-run behavior
• Argument parsing for each subcommand
• Error code mapping

cargo test --locked -p cosh-cli
# ~55 tests, ~4s

cosh-core

Test File	Coverage
tests/jsonl_protocol.rs	JSONL message serialization/deserialization
tests/registry_protocol.rs	Registry mode request-response
tests/tool_approval.rs	Tool approval protocol
tests/sls_integration.rs	SLS logging integration

Unit tests distributed across modules:

• extension/ — Configuration parsing, variable substitution, extension loading
• state.rs — State file read/write
• hook.rs — Hook protocol

cargo test --locked -p cosh-core

cosh-shell

Most complex test structure, divided into three layers:

Integration tests (crates/cosh-shell/tests/):

Directory	Coverage
logic/	Command classification, failure analysis, agent event handling
protocol/	Adapter protocol, control messages
raw_cli/	Raw mode CLI behavior
shell_host/	PTY sessions, OSC marker parsing

Inline unit tests (#[cfg(test)] modules in src/):

Module	Coverage
approval/tests.rs	Approval decision logic
hooks/	Hook engine, runtime behavior
runtime/	State machine, evidence requests
shell_host/osc_tests.rs	OSC escape sequence parsing
tools/	Tool risk analysis, display

cargo test --locked -p cosh-shell
# Slower (PTY tests require fork + terminal interaction)

Test Utilities

Utility	Purpose
tempfile	Create temporary directories for isolated tests
COSH_STATES_DIR	Environment variable to override state directory
ExtensionManager::new_isolated()	Test-specific constructor

Writing Tests Guide

1. Integration tests go in tests/ directory, unit tests inline in modules
2. Test function naming: test_<behavior_under_test>_<scenario>
3. Use tempfile::tempdir() to isolate filesystem side effects
4. Do not depend on network (LLM API tests use mocks)
5. PTY tests annotated with #[ignore] (if they require a real terminal environment)