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Unit tests & boundaries

Your services, actors, and workflows are ordinary TypeScript functions. Dependencies are boundaries. Boundaries should be mocked from contract examples, not invented response shapes.

Boundary router pattern

import { createBoundaryRouter } from "hobo/runtime";
import { expect, test } from "node:test";

const router = createBoundaryRouter();

const payments = router.boundary<Charge, Receipt>("payments").mock([
 {
 input: { orderId: "o-1", amount: 42 },
 output: { orderId: "o-1", status: "charged" },
 },
]);

test("checkout charges the cart", async => {
 const receipt = await payments.call({ orderId: "o-1", amount: 42 });
 expect(receipt.status).toBe("charged");
});
  • Matched inputs return the example’s output.
  • Unmatched inputs still get a correctly-typed canned response (first example) so tests stay unblocked.
  • Greenfield declared operations work the same way: contract-derived stubs serve day-one traffic and record specification-by-example traces.

Trainables

A @trainable / @operation contract’s examples double as its eval suite. Resolve the same instance by token in a test; those assertions are what the training loop reuses later.

Aggregate / CQRS unit style

Write-model aggregates fold streams and emit past-tense facts. Unit tests typically:

  1. Use an in-memory EventStore or a temp SQLite partition.
  2. Acquire a lease (in-memory ActorHost for pure unit speed, durable host for lease persistence).
  3. Assert appended facts and folded state — never assert on mutable read models the aggregate should not touch.

Prefer package-scoped runs

run the package tests
run the package tests

Do not use full-repo test globs as a discovery tool. Search first.

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