then — Assertions

The testing/then package provides helpers for asserting outcomes in tests — specifically, what events are present in the store after an action.

import "github.com/err0r500/fairway/testing/then"

---

ExpectEventsInStore

Asserts that the store contains exactly the given events (order-independent).

func ExpectEventsInStore(t *testing.T, store dcb.DcbStore, events ...fairway.Event)

What it checks

• Reads all events from the store via ReadAll
• Compares events by type, tags, and inner data (the data field of the JSON envelope)
• Ignores the occurredAt timestamp (so NewEvent(...) can be used directly in assertions)
• Uses assert.ElementsMatch — order does not matter

Example

func TestCreateList(t *testing.T) {
    store, server, client := given.FreshSetup(t, Register)

    client.R().
        SetBody(map[string]string{"name": "Shopping"}).
        Post(server.URL + "/api/lists/my-list")

    then.ExpectEventsInStore(t, store,
        fairway.NewEvent(ListCreated{ListId: "my-list", Name: "Shopping"}),
    )
}

Multiple Events

then.ExpectEventsInStore(t, store,
    fairway.NewEvent(ListCreated{ListId: "l1", Name: "Shopping"}),
    fairway.NewEvent(ItemAdded{ListId: "l1", ItemId: "i1", Text: "Milk"}),
)

The assertion passes regardless of the order the events were appended.

Comparison Details

Internally, each event is compared as:

type eventForComparison struct {
    Type string
    Tags []string
    Data json.RawMessage  // inner data only, not the full envelope
}

This means:

• The type name ("ListCreated") must match
• All tags must match exactly
• The JSON representation of the inner struct must match field-for-field

Tip

Pass the same struct values you expect to appear. then.ExpectEventsInStore will serialize and compare them just as the store would.

---

Test Pattern Summary

func TestAddItem(t *testing.T) {
    // GIVEN
    store, server, client := given.FreshSetup(t, Register)
    given.EventsInStore(store,
        fairway.NewEvent(ListCreated{ListId: "my-list", Name: "Shopping"}),
    )

    // WHEN
    client.R().
        SetBody(map[string]string{"text": "Milk"}).
        Post(server.URL + "/api/lists/my-list/items/item-1")

    // THEN
    then.ExpectEventsInStore(t, store,
        fairway.NewEvent(ListCreated{ListId: "my-list", Name: "Shopping"}),
        fairway.NewEvent(ItemAdded{ListId: "my-list", ItemId: "item-1", Text: "Milk"}),
    )
}