yaab.testing

Offline deterministic models for tests and examples.

yaab.testing

Testing utilities — deterministic models and fixtures, no API keys needed.

CassetteMiss

Bases: YaabError

Raised when a CassetteModel in replay mode has no recorded interaction matching a request (unknown key, or the recorded sequence is exhausted).

CassetteModel

Record/replay wrapper around a ModelProvider.

modes: record (always call inner, append), once (replay if present else call+append), replay (replay only; miss -> CassetteMiss).

FunctionModel

A model whose response is computed by a user-supplied function.

TestModel

A scripted, deterministic model.

Parameters

custom_output: Text to return as the final assistant message. responses: A sequence of :class:ModelResponse (or strings) returned in order, one per complete call. Overrides custom_output when set. call_tools: Tool names to call (with empty args) on the first response, before producing a final text answer. Useful for exercising the tool loop. structured_output: A dict returned (JSON-encoded) when the agent requests structured output, so output validation can be tested without a real model.

use_cassette

use_cassette(path: str | Path, *, inner: ModelProvider | None = None, mode: Literal['once', 'record', 'replay'] | None = None) -> Iterator[CassetteModel]

Yield a CassetteModel. mode defaults from env: YAAB_RECORD=1 with an inner records, otherwise replays — so devs record once and CI replays.