import { InMemoryEventStore } from "./streamable-event-store.js";
import type { JSONRPCMessage } from "@modelcontextprotocol/sdk/types.js";
const createMessage = (method: string): JSONRPCMessage =>
({
jsonrpc: "2.0",
method,
}) as JSONRPCMessage;
describe("InMemoryEventStore replay behavior", () => {
beforeEach(() => {
jest.useFakeTimers();
});
afterEach(() => {
jest.useRealTimers();
});
it("replays events after the anchor when older events are evicted", async () => {
const store = new InMemoryEventStore(undefined, { maxEventAgeMs: 1000 });
const streamId = "stream-1";
jest.setSystemTime(new Date("2026-01-01T00:00:00.000Z"));
await store.storeEvent(streamId, createMessage("event-1"));
jest.setSystemTime(new Date("2026-01-01T00:00:00.400Z"));
const event2 = await store.storeEvent(streamId, createMessage("event-2"));
jest.setSystemTime(new Date("2026-01-01T00:00:00.600Z"));
const event3 = await store.storeEvent(streamId, createMessage("event-3"));
jest.setSystemTime(new Date("2026-01-01T00:00:01.200Z"));
const sent: string[] = [];
await store.replayEventsAfter(event2, {
send: async (eventId) => {
sent.push(String(eventId));
},
});
expect(sent).toEqual([String(event3)]);
});
it("throws when last event id expires during replay", async () => {
const store = new InMemoryEventStore(undefined, { maxEventAgeMs: 1000 });
const streamId = "stream-2";
jest.setSystemTime(new Date("2026-01-01T00:00:00.000Z"));
const event1 = await store.storeEvent(streamId, createMessage("event-1"));
jest.setSystemTime(new Date("2026-01-01T00:00:00.500Z"));
await store.storeEvent(streamId, createMessage("event-2"));
jest.setSystemTime(new Date("2026-01-01T00:00:01.600Z"));
await expect(
store.replayEventsAfter(event1, {
send: async () => {},
}),
).rejects.toThrow("Last-Event-ID expired");
});
});
