Runs a corpus case that carries a host object (ADR-0070 decision 5): the host registers the case's send_types (ADR-0069), and the sends handed to it must be the case's expect_sends.

Statifier.Testing.Case.test_scxml/4 starts its session with no registration, so a host case runs here instead, through the same public session API: Statifier.start_session/2 with :send_types naming Mix.Statifier.Corpus.HostCase.Processor for every registered type, Statifier.Session.send_event/2 for each step, and Statifier.Session.status/1 and Statifier.Session.snapshot/1 to wait for the chart to settle and read its active leaf states. The waiting follows test_scxml/4's: a pending library timer is given a short window to fire before the next event, and a configuration is read once the session has had nothing queued and no timer pending on two consecutive polls, or the chart has left the running status, or a deadline passed.

A case agrees when the active leaf states after initialization and after every step are the ones it expects, and the sends handed to the processor over the whole run, in order, are exactly its expect_sends. Each handed send is written in the case's language-neutral item shape: type, target, event with its name and, when the send carries a payload, its data; delay_ms for a delayed send; and send_id only when the author named the send, which is when the delivered event carries one. A registered delayed send is the host's timer, and this host never fires one.