Builders for valid typed LemonCore.Events.* payloads, for use in tests.

Tests that publish onto LemonCore.Bus used to hand-construct raw payload maps:

LemonCore.Bus.broadcast(
  LemonCore.Bus.run_topic(run_id),
  LemonCore.Event.new(:run_completed, %{completed: %{ok: true, answer: "Done"}}, meta)
)

A raw map drifts from the contract the moment a field is added, renamed, or made mandatory — and it silently omits enforced keys (the %{seq: 1, text: "..."} delta map above is missing its run_id, which the typed Delta requires). These builders produce the real struct instead, so a test payload is exactly as valid as a production one:

LemonCore.Bus.broadcast(
  LemonCore.Bus.run_topic(run_id),
  LemonCore.Event.new(:run_completed, EventsFixtures.run_completed(answer: "Done"), meta)
)

Defaults and overrides

Every builder fills the payload's enforced keys with sensible sample values and leaves optional keys at their struct default, so a no-argument call is always a valid payload. Pass a keyword list or map to override any field:

EventsFixtures.delta(text: "chunk two", seq: 2)
EventsFixtures.run_started(run_id: "run_42", engine: "native")

Unknown keys raise, because each builder ends in the payload's strict new/1 — a typo in a test fixture should fail at the fixture, not surface as a nil field three assertions later.

Nested payloads

Payloads that wrap another payload accept shorthand: fields belonging to the nested struct can be passed at the top level and are routed inward. For run_completed the nested LemonCore.Events.Completion fields (:ok, :answer, :error, :usage, …) are lifted automatically:

EventsFixtures.run_completed(ok: false, error: :timeout, duration_ms: 30)

Pass :completed (a Completion struct or an attrs map) explicitly to build it yourself; an explicit :completed wins over any shorthand. The nested builders (completion/1, action/1, approval_pending/1) are public so you can compose them directly.

This module is the fixture companion to LemonPlatformTest.EventsCase, which asserts the payload contract. Like that case, it needs :lemon_core (the EventsCase -> lemon_core row in the kit's dep table); anyone building event payloads already has it.