# Conformance suite

pytest tests that assert an emulator correctly implements the control contract

(`../SPEC.md`, 0.1.x). Point them at any emulator — the reference x16emu, FAB,

the Neo6502 — and they check the same surface. Platform-agnostic: framebuffer

dimensions come from the PPM header, addresses use `$0000`, and `bank` is

exercised without requiring the platform to have banking.

## Run

Attach to an already-running emulator:

```

RRDC_PORT=8080 pytest -v

```

Or let the suite launch one (`{port}` is substituted into the command):

```

RRDC_EMU_CMD="SDL_VIDEODRIVER=dummy SDL_AUDIODRIVER=dummy \

    /path/to/x16emu -rom rom.bin -warp -controlport {port}" \

RRDC_PORT=8391 pytest -v

```

If nothing is listening and no `RRDC_EMU_CMD` is set, the tests **skip** (a bare

`pytest` in CI without an emulator is a skip, not a failure).

## What it checks

- `/status` — required keys present, contract MAJOR matches, sane types.

- `/regs` — a non-empty JSON object of integer registers.

- `/mem` — returns exactly `len` bytes; honours `bank`.

- `/screenshot` — a well-formed PPM whose body size matches its dimensions.

- `/step` — deterministic: equal steps advance the frame counter by equal,

  positive amounts, and `/step` returns the halted counter.

- `/pause` + `/resume` — toggle the paused state.

- Errors — unknown path → 404; `GET /step` → 405.

## Environment

| Var | Default | Meaning |

|---|---|---|

| `RRDC_PORT` | `8080` | control port to attach to / launch on |

| `RRDC_EMU_CMD` | — | shell command to launch an emulator (`{port}` substituted) |

| `RRDC_BOOT_TIMEOUT` | `20` | seconds to wait for `/status` |

Requires `pytest`. Nothing else — the client is stdlib-only (Pillow is optional

and unused here).