lith

Docs Package reference

events/eventstest

Tests deciders as given, when, then: the events a stream holds, a command, and the events or the error the command should cause.

Import path github.com/zweiundeins/lith/events/eventstest. Generated from the doc comments in events/eventstest/.

It runs the fold and the decision without a database.

Go
func TestRename(t *testing.T) {
	eventstest.For(rename).
		Given(CardCreated{Title: "Draft"}).
		When(Rename{Title: "Final"}).
		Then(t, CardRenamed{From: "Draft", To: "Final"})
}

Functions

func Samples

Go
func Samples[K events.Key, E any](t testing.TB, st *events.Store, s *events.Stream[K, E], fsys fs.FS)

Samples checks the JSON samples of a stream's event types in fsys, a file per type named after it, such as card.renamed.json: every type of the stream has one, and each decodes, without a field its type lacks, and upcasts (events.CheckSample). Keep a sample of every type as it was first stored, and never change one: a field renamed instead of upcast then fails the test instead of the reads in production.

Types

type Case

Go
type Case[C, E, S any] struct {
	// contains filtered or unexported fields
}

Case is a decider's test case. Given and When return a new Case, so a case can serve as the start of several.

func For

Go
func For[C, E, S any](d events.Decider[C, E, S]) Case[C, E, S]

For starts a test case of decider d.

func (Case[C, E, S]) Given

Go
func (c Case[C, E, S]) Given(evs ...E) Case[C, E, S]

Given adds events that the stream holds before the command.

func (Case[C, E, S]) State

Go
func (c Case[C, E, S]) State() S

State returns the state folded from the given events.

func (Case[C, E, S]) Then

Go
func (c Case[C, E, S]) Then(t testing.TB, want ...E)

Then checks that the command causes exactly the events want, in order, and no error. Then(t) checks that it causes nothing.

func (Case[C, E, S]) ThenError

Go
func (c Case[C, E, S]) ThenError(t testing.TB, want error)

ThenError checks that the command fails with want: an error that errors.Is matches, or one with the same message, such as a *writer.Refusal.

func (Case[C, E, S]) When

Go
func (c Case[C, E, S]) When(cmd C) Case[C, E, S]

When sets the command.