Testing with Test Harness

createTestHarness(actor) instruments an actor, builds its graph, and records every state visit, transition, and effect.

Setup

import { createTestHarness } from "@mantaq/test";

const harness = createTestHarness(createCheckoutActor());

Use harness.send() instead of actor.send(). All sends are recorded.

Drive and assert

harness.send(submitBasicInfo.create());
harness.send(submitShipping.create());
harness.send(submitPayment.create());
harness.send(paymentOk.create());

harness.assertStateVisited("basicInfo");
harness.assertStateVisited("success");
harness.assertAllStatesVisited();

Assertion methods

• assertStateVisited(id) / assertStateNeverVisited(id)
• assertTransitionVisited(from, eventId) / assertTransitionNeverVisited(from, eventId)
• assertEffectRan(id) / assertEffectNeverRan(id)
• assertAllStatesVisited() / assertAllTransitionsVisited()
• assertContextNever(predicate) fails if predicate matches current context

Query helpers

Non-throwing, return booleans:

harness.wasStateVisited("payment");
harness.wasTransitionVisited("payment", "submitPayment");

Coverage report

const report = harness.coverage();
// report.percent.states     — 0–100
// report.percent.transitions — 0–100
// report.states.uncovered    — string[]
// report.transitions.uncovered — Array<{ from, event }>

Use report.percent to gate CI. Use uncovered to find missing paths.

Reset

harness.reset() clears history between test cases.