Story

story() runs a scenario against a fresh in-memory runtime and returns a tuple. Thrown assertions become Unexpected.

Import

import { fail, ok, story } from '@marcelsud/accord'

Usage

const [value, error] = await story(Bank, async (test) => {
  const [, givenError] = await test.given(Account, 'a-1', [Opened()])
  if (givenError !== null) return fail(givenError)

  const [receipt, commandError] = await test.bank.account.deposit('a-1', { amount: 100 })
  if (commandError !== null) return fail(commandError)

  test.equal(receipt.reply.balance, 100)
  return ok(undefined)
})

if (error !== null) throw error

The test context

test.bank

A wired runtime for the model.

test.given(aggregate, id, events)

Seeds an event-evolved aggregate with history. It validates and folds the events into a fresh instance. Seeded events rebuild views and projections but don't run policies. Class and factory aggregates can't be seeded this way; call their methods instead.

test.equal(actual, expected)

Deep strict equality. Throws on mismatch, which the story reports as Unexpected.

Options

story(model, body, options?) accepts the same options as wire(): storage and services. services is required when the model declares dependencies.

await story(Bank, body, { services: { rules: { maximum: 1_000 } } })

See Testing.