Testing API

The public test adapter, inbox, simulations, and Vitest matchers.

createTestAdapter(options?) returns a standard Adapter plus test-only APIs:

API	Purpose
`adapter.inbox.all()`	Return a defensive copy of recorded emails
`adapter.inbox.first()`, `last()`, `at(index)`	Read a recorded email or throw when absent
`adapter.inbox.to(email)`	Filter `to`, `cc`, and `bcc` case-insensitively
`adapter.inbox.from(email)`	Filter sender
`adapter.inbox.withSubject(query)`	Filter exact or regular-expression subject
`adapter.calls`	Include all sends, including failures
`adapter.failNext()`	Queue deterministic failures
`adapter.failAlways()`	Fail every send until reset
`adapter.failIf()`	Fail messages selected by a predicate
`adapter.reset()`	Clear inbox, calls, and simulations

Import @postbote/testing/matchers once in your Vitest setup file to add toHaveSentEmail, toHaveSentEmailTo, and toHaveSentEmailMatching.