Files
fusion/packages/dashboard/app/__tests__/sse-bus.test.ts
2026-04-17 14:31:43 -07:00

133 lines
4.1 KiB
TypeScript

import { describe, it, expect, afterEach } from "vitest";
import { MockEventSource } from "../../vitest.setup";
import { subscribeSse, __resetSseBus, __sseBusChannelCount } from "../sse-bus";
afterEach(() => {
__resetSseBus();
});
describe("sse-bus", () => {
it("opens one EventSource per URL regardless of subscriber count", () => {
const url = "/api/events?projectId=p1";
const unsubA = subscribeSse(url, { events: { "task:created": () => {} } });
const unsubB = subscribeSse(url, { events: { "task:updated": () => {} } });
const unsubC = subscribeSse(url, { events: { "task:deleted": () => {} } });
const sources = MockEventSource.instances.filter((es) => es.url === url);
expect(sources).toHaveLength(1);
unsubA();
unsubB();
unsubC();
});
it("opens separate EventSources for different URLs", () => {
const unsubA = subscribeSse("/api/events", {});
const unsubB = subscribeSse("/api/events?projectId=p1", {});
expect(MockEventSource.instances).toHaveLength(2);
unsubA();
unsubB();
});
it("dispatches events to every subscriber of the same URL", () => {
const url = "/api/events";
const receivedA: unknown[] = [];
const receivedB: unknown[] = [];
const unsubA = subscribeSse(url, {
events: { "task:created": (e) => receivedA.push(JSON.parse(e.data)) },
});
const unsubB = subscribeSse(url, {
events: { "task:created": (e) => receivedB.push(JSON.parse(e.data)) },
});
const es = MockEventSource.instances[0];
es._emit("task:created", { id: "t-1" });
expect(receivedA).toEqual([{ id: "t-1" }]);
expect(receivedB).toEqual([{ id: "t-1" }]);
unsubA();
unsubB();
});
it("closes the EventSource when the last subscriber unsubscribes", () => {
const url = "/api/events";
const unsubA = subscribeSse(url, {});
const unsubB = subscribeSse(url, {});
expect(__sseBusChannelCount()).toBe(1);
const es = MockEventSource.instances[0];
unsubA();
expect(es.close).not.toHaveBeenCalled();
unsubB();
expect(es.close).toHaveBeenCalledTimes(1);
expect(__sseBusChannelCount()).toBe(0);
});
it("stops dispatching to a subscriber after it unsubscribes", () => {
const url = "/api/events";
const received: unknown[] = [];
const unsub = subscribeSse(url, {
events: { "task:created": (e) => received.push(JSON.parse(e.data)) },
});
const es = MockEventSource.instances[0];
es._emit("task:created", { id: "t-1" });
expect(received).toEqual([{ id: "t-1" }]);
unsub();
// Another subscriber keeps the channel alive so we can assert the old handler is gone.
const unsub2 = subscribeSse(url, {});
es._emit("task:created", { id: "t-2" });
expect(received).toEqual([{ id: "t-1" }]);
unsub2();
});
it("attaches native listeners lazily as new event types are subscribed", () => {
const url = "/api/events";
const unsubA = subscribeSse(url, { events: { "task:created": () => {} } });
const es = MockEventSource.instances[0];
expect(Object.keys(es.listeners)).toEqual(
expect.arrayContaining(["task:created"])
);
expect(es.listeners["task:updated"]).toBeUndefined();
const unsubB = subscribeSse(url, { events: { "task:updated": () => {} } });
expect(es.listeners["task:updated"]).toBeDefined();
unsubA();
unsubB();
});
it("fires onOpen for every subscriber on initial connect", () => {
const url = "/api/events";
let opensA = 0;
let opensB = 0;
const unsubA = subscribeSse(url, { onOpen: () => opensA++ });
const unsubB = subscribeSse(url, { onOpen: () => opensB++ });
const es = MockEventSource.instances[0];
es._emit("open");
expect(opensA).toBe(1);
expect(opensB).toBe(1);
unsubA();
unsubB();
});
it("fires onReconnect whenever the channel is rebuilt", () => {
const url = "/api/events";
let reconnects = 0;
const unsub = subscribeSse(url, {
onReconnect: () => reconnects++,
});
const es = MockEventSource.instances[0];
// An error that tears down the connection triggers a resync signal.
es._emit("error");
expect(reconnects).toBe(1);
unsub();
});
});