prometeu-runtime/files/Tests.md

Layered Test Suite Architecture (PR‑8.3)

Overview

• Tests are organized by runtime layer to isolate failures and clarify ownership of behavior.
• Location: crates/dev/prometeu-layer-tests/tests/

Layers and representative tests

1. Bytecode encode/decode
   • bytecode_encode_decode.rs — round‑trip decoding for edge immediates and structure.
2. Verifier
   • verifier_closure_reject.rs — rejects CALL_CLOSURE when TOS is not a closure.
   • Rule: verifier tests never run the VM.
3. VM execution
   • vm_exec_valid.rs — executes a tiny valid program; assumes verified input.
   • Rule: VM tests do not depend on the verifier; they prepare ROM directly.
4. GC behavior
   • gc_collect_unreachable.rs — unrooted closure is reclaimed; rooted one survives.
5. Scheduler behavior
   • scheduler_determinism.rs — deterministic FIFO ordering for same‑tick wakeups.

Running the layered suite

• Run just the layered tests: cargo test -p prometeu-layer-tests
• Run the entire workspace: cargo test

Separation of concerns

• No cross‑layer assumptions in these tests.
• Verifier tests: no VirtualMachine execution.
• VM tests: assume pre‑verified bytecode; interact via public VM APIs only.
• GC and Scheduler tests: exercise their public APIs directly, without booting the VM.

DRY helpers

• Shared utilities should live in crates/dev/prometeu-test-support when needed. The current minimal suite avoids duplication by using tiny local helpers.