Fixture

Tests an aggregate in isolation: given these events, when this command runs, what happens? The moleculer-cqrs CQRSFixture, as a chain that runs when it is yielded:

yield* Fixture.make(Todo)
  .givenEvents([created])
  .when("deleteTodo", { message: "Done" })
  .expectEvent("TodoDeleted")
  .inspectState((state) => assert.strictEqual(state.status, "deleted"))

Commands run through the real AggregateService on an in-memory store, so payload validation and event encoding are exercised too.

The history can include events stored in older versions of their schema, made with Aggregate.historical, which then go through the same upcasting as events read from a real store.

Classes

ExpectationFailed

Defined in: src/Fixture.ts:31

Raised as a defect, so a command’s error channel only holds what the command can do.

Extends

object & YieldableError<this>

Constructors

Constructor

new ExpectationFailed(…args): ExpectationFailed

Defined in: node_modules/.pnpm/effect@4.0.6/node_modules/effect/dist/Schema.d.ts:10979

Parameters

args

…[props: object, options?: MakeOptions]

Returns

ExpectationFailed

Inherited from

Schema.TaggedError<ExpectationFailed>()("ExpectationFailed", { message: Schema.String, expected: Schema.Unknown, actual: Schema.Unknown }).constructor

Properties

actual

readonly actual: unknown = Schema.Unknown

Defined in: src/Fixture.ts:34

Inherited from

Schema.TaggedError<ExpectationFailed>()("ExpectationFailed", { message: Schema.String, expected: Schema.Unknown, actual: Schema.Unknown }).actual

expected

readonly expected: unknown = Schema.Unknown

Defined in: src/Fixture.ts:33

Inherited from

Schema.TaggedError<ExpectationFailed>()("ExpectationFailed", { message: Schema.String, expected: Schema.Unknown, actual: Schema.Unknown }).expected

message

message: string = Schema.String

Defined in: src/Fixture.ts:32

Inherited from

Schema.TaggedError<ExpectationFailed>()("ExpectationFailed", { message: Schema.String, expected: Schema.Unknown, actual: Schema.Unknown }).message

Interfaces

Fixture

Defined in: src/Fixture.ts:97

Type Parameters

A

A extends Any

Properties

state

readonly state: Effect<State<A>, ReadError, Context<A>>

Defined in: src/Fixture.ts:103

The state after the given events, without running a command.

Methods

checkInvariants()

checkInvariants(options): Effect<void, never, Context<A>>

Defined in: src/Fixture.ts:123

Runs random sequences of commands from the given history and checks that the invariant holds after each one that succeeds. Commands that fail are part of the game and are skipped. A violation dies with ExpectationFailed, holding the shortest sequence found that breaks it.

Parameters

options

InvariantOptions<A>

Returns

Effect<void, never, Context<A>>

given()

given(events): Fixture<A>

Defined in: src/Fixture.ts:99

Replaces the history the next command runs against.

Parameters

events

readonly GivenEvent<A>[]

Returns

Fixture<A>

givenEvents()

givenEvents(events?, aggregateId?): Fixture<A>

Defined in: src/Fixture.ts:101

Like given, starting from an empty history by default and optionally switching aggregate id.

Parameters

events?

readonly GivenEvent<A>[]

aggregateId?

string

Returns

Fixture<A>

inspectState()

inspectState(check): Scenario<A, ReadError, Context<A>>

Defined in: src/Fixture.ts:105

Passes the state after the given events to a callback, which throws to fail the test.

Parameters

check

(state) => void

Returns

Scenario<A, ReadError, Context<A>>

when()

when<K>(command, payload): Scenario<A, CommandFailure | CommandError<A, K>, Context<A>>

Defined in: src/Fixture.ts:108

Type Parameters

K

K extends string

Parameters

command

K

payload

Payload<A, K>

Returns

Scenario<A, CommandFailure | CommandError<A, K>, Context<A>>

whenFails()

whenFails<K>(command, payload): Effect<CommandFailure | CommandError<A, K>, never, Context<A>>

Defined in: src/Fixture.ts:113

Runs a command that is expected to fail and returns the error. Dies if it succeeds.

Type Parameters

K

K extends string

Parameters

command

K

payload

Payload<A, K>

Returns

Effect<CommandFailure | CommandError<A, K>, never, Context<A>>

InvariantOptions

Defined in: src/Fixture.ts:56

Type Parameters

A

A extends Any

Properties

check?

readonly optional check?: CheckOptions

Defined in: src/Fixture.ts:71

Passed on to Arbitrary.checkEffect, for the number of runs or a seed.

commands?

readonly optional commands?: { readonly [K in string]?: false | Arbitrary<Payload<A, K>> }

Defined in: src/Fixture.ts:63

How to generate each command’s payload. By default it comes from the payload schema. false leaves a command out.

invariant

readonly invariant: (state) => boolean

Defined in: src/Fixture.ts:58

Must hold for the given state and after every command that succeeds.

Parameters

state

State<A>

Returns

boolean

maxCommands?

readonly optional maxCommands?: number

Defined in: src/Fixture.ts:69

The longest sequence of commands to try. Defaults to 20.

Outcome

Defined in: src/Fixture.ts:37

Type Parameters

A

A extends Any

Properties

events

readonly events: readonly Event<A>[]

Defined in: src/Fixture.ts:38

fixture

readonly fixture: Fixture<A>

Defined in: src/Fixture.ts:42

Continues from here, with this outcome’s events as the new history.

state

readonly state: State<A>

Defined in: src/Fixture.ts:39

version

readonly version: number

Defined in: src/Fixture.ts:40

Scenario

Defined in: src/Fixture.ts:78

The steps so far. Nothing runs until it is yielded or run as an Effect, which produces the Outcome of the last command.

Extends

Effect<Outcome<A>, E, R>

Type Parameters

A

A extends Any

E

E

R

R

Methods

expectEvent()

expectEvent(event): Scenario<A, E, R>

Defined in: src/Fixture.ts:90

Expects the last command to have emitted exactly this event.

Parameters

event

ExpectedEvent<A>

Returns

Scenario<A, E, R>

expectEvents()

expectEvents(events): Scenario<A, E, R>

Defined in: src/Fixture.ts:92

Expects the last command to have emitted exactly these events, in order.

Parameters

events

readonly ExpectedEvent<A>[]

Returns

Scenario<A, E, R>

inspectState()

inspectState(check): Scenario<A, E, R>

Defined in: src/Fixture.ts:94

Passes the current state to a callback, which throws to fail the test.

Parameters

check

(state) => void

Returns

Scenario<A, E, R>

when()

when<K>(command, payload): Scenario<A, CommandFailure | E | CommandError<A, K>, R | Context<A>>

Defined in: src/Fixture.ts:80

Runs another command on top of the previous one.

Type Parameters

K

K extends string

Parameters

command

K

payload

Payload<A, K>

Returns

Scenario<A, CommandFailure | E | CommandError<A, K>, R | Context<A>>

whenFails()

whenFails<K>(command, payload): Effect<CommandFailure | CommandError<A, K>, E, R | Context<A>>

Defined in: src/Fixture.ts:85

Runs a command that is expected to fail and returns the error. Dies if it succeeds.

Type Parameters

K

K extends string

Parameters

command

K

payload

Payload<A, K>

Returns

Effect<CommandFailure | CommandError<A, K>, E, R | Context<A>>

Type Aliases

ExpectedEvent

ExpectedEvent<A> = Event<A> | Event<A>["_tag"]

Defined in: src/Fixture.ts:46

An event to compare with, or only its tag when the rest doesn’t matter.

Type Parameters

A

A extends Any

GivenEvent

GivenEvent<A> = Event<A> | Historical

Defined in: src/Fixture.ts:49

An event in today’s shape, or one stored in an older version of its schema.

Type Parameters

A

A extends Any

Step

Step<A> = { readonly [K in CommandName<A>]: { command: K; payload: Payload<A, K> } }[CommandName<A>]

Defined in: src/Fixture.ts:52

One generated step of Fixture.checkInvariants.

Type Parameters

A

A extends Any

Functions

make()

make<A>(aggregate, options?): Fixture<A>

Defined in: src/Fixture.ts:188

Type Parameters

A

A extends Any

Parameters

aggregate

A

options?

aggregateId?

string

events?

readonly GivenEvent<A>[]

Returns

Fixture<A>