Implements docs/contracts/issues/1.contract.md. Four entry points
(stream_turn, reconnect_turn, cancel_turn, _parse_sse_id) + nine
typed Event variants + ten domain exceptions. 37 tests covering
every TESTS: entry verbatim, plus the boundary smoke test still
passes.
Tracer-bullet ordering per the contract's per-FN tracer tags:
_parse_sse_id (foundation; happy_simple) → stream_turn
(happy_one_text_done) → reconnect_turn (happy_resume_from_seq_3) →
cancel_turn (happy_cancel). Each FN's tracer went RED then GREEN
before its other tests landed.
Shared SSE-iteration logic (INV-002 sse_id presence + INV-003
turn_id stability + terminal-break) lives in private _iter_events
helper. expected_turn_id=None gives stream_turn's "establish from
first event" semantics; expected_turn_id=N gives reconnect_turn's
"first event is already a flip-candidate" semantics — the
two-entry-point distinction Volva surfaced during the paraphrase
round.
A few implementation choices worth recording:
- _parse_sse_id uses a `^-?\\d+$` regex pre-check to reject any
whitespace before int() is called. Python's `int(" 3 ")` silently
strips, which would have made the trailing_whitespace adversarial
test pass for the wrong reason.
- The connection_drop test uses a custom httpx.AsyncByteStream
subclass (_DropAfter) that yields chunks then raises
RemoteProtocolError mid-stream. respx alone can't simulate
mid-stream HTTP errors.
- ToolResult.result and ToolStart.arguments are typed as Any
because the server's tool wire shape varies per tool; the spec
doesn't pin a generic schema.
- Boundary smoke test (no core.* / worldtree.* imports under
src/ratatoskr/) still GREEN — INV-005 holds.
Also: one E501 line-length fix in test_no_worldtree_imports.py
that ruff flagged once the new tests pulled it into scope.
vh