Files
stack/apps/web/src/lib/socket.spec.ts
T

99 lines
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TypeScript

import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
const { ioMock } = vi.hoisted(() => ({
ioMock: vi.fn(),
}));
vi.mock('socket.io-client', () => ({
io: ioMock,
}));
import { destroySocket, getSocket } from './socket';
interface MockChatSocket {
on: ReturnType<typeof vi.fn>;
offAny: ReturnType<typeof vi.fn>;
disconnect: ReturnType<typeof vi.fn>;
/** Test-only helper: fires every handler registered for `event` via
* `.on`, mirroring how a real socket.io-client instance invokes its own
* listeners (e.g. calling the registered `disconnect` handler(s) on a
* real transient disconnect). */
trigger(event: string): void;
}
function createMockSocket(): MockChatSocket {
const handlers = new Map<string, Set<() => void>>();
const mockSocket: MockChatSocket = {
on: vi.fn((event: string, handler: () => void) => {
if (!handlers.has(event)) handlers.set(event, new Set());
handlers.get(event)?.add(handler);
return mockSocket;
}),
offAny: vi.fn(() => mockSocket),
disconnect: vi.fn(() => mockSocket),
trigger(event: string): void {
for (const handler of handlers.get(event) ?? []) handler();
},
};
return mockSocket;
}
let currentMock!: MockChatSocket;
describe('chat socket', () => {
beforeEach(() => {
ioMock.mockReset();
// A fresh object per io() call so identity assertions (same singleton vs.
// a genuinely new instance) are meaningful.
ioMock.mockImplementation(() => {
currentMock = createMockSocket();
return currentMock;
});
});
afterEach(() => {
destroySocket();
});
it('creates one same-origin /chat namespace socket', () => {
const first = getSocket();
const second = getSocket();
expect(first).toBe(second);
expect(ioMock).toHaveBeenCalledOnce();
expect(ioMock).toHaveBeenCalledWith('/chat', {
withCredentials: true,
autoConnect: false,
transports: ['websocket', 'polling'],
});
});
it('keeps the same singleton instance across a transient disconnect', () => {
const first = getSocket();
// socket.ts must not react to a real socket's `disconnect` event by
// nulling the singleton — it registers no such handler at all now.
// Actually fire every handler registered via `.on('disconnect', ...)`
// (mirroring a real socket.io-client reconnect) instead of merely
// calling getSocket() again: this is what makes the test fail if
// production reintroduces `socket.on('disconnect', () => { socket =
// null; })`, since that handler would run here and null the singleton
// before the next getSocket() call.
currentMock.trigger('disconnect');
const second = getSocket();
expect(second).toBe(first);
expect(ioMock).toHaveBeenCalledOnce();
});
it('only creates a new singleton after an explicit destroySocket()', () => {
const first = getSocket();
destroySocket();
const second = getSocket();
expect(second).not.toBe(first);
expect(ioMock).toHaveBeenCalledTimes(2);
});
});