client/js/src/test/stream.test.ts

import { vi, type Mock } from "vitest";
import { Client } from "../client";
import { readable_stream } from "../utils/stream";
import { initialise_server } from "./server";
import { direct_space_url } from "./handlers.ts";

import {
	describe,
	it,
	expect,
	afterEach,
	beforeAll,
	afterAll,
	beforeEach
} from "vitest";

const server = initialise_server();

beforeAll(() => server.listen());
afterEach(() => server.resetHandlers());
afterAll(() => server.close());

describe("open_stream", () => {
	let app: Client;

	beforeEach(async () => {
		app = await Client.connect("hmb/hello_world");
		app.stream = vi.fn().mockImplementation(() => {
			app.stream_instance = readable_stream(
				new URL(`${direct_space_url}/queue/data`)
			);
			return app.stream_instance;
		});
	});

	afterEach(() => {
		vi.clearAllMocks();
	});

	it("should throw an error if config is not defined", () => {
		app.config = undefined;

		expect(async () => {
			await app.open_stream();
		}).rejects.toThrow("Could not resolve app config");
	});

	it("should connect to the SSE endpoint and handle messages", async () => {
		await app.open_stream();

		const eventsource_mock_call = (app.stream as Mock).mock.calls[0][0];

		expect(eventsource_mock_call.href).toMatch(
			/https:\/\/hmb-hello-world\.hf\.space\/queue\/data\?session_hash/
		);

		expect(app.stream).toHaveBeenCalledWith(eventsource_mock_call);

		if (!app.stream_instance?.onmessage || !app.stream_instance?.onerror) {
			throw new Error("stream instance is not defined");
		}

		const onMessageCallback = app.stream_instance.onmessage.bind(app);
		const onErrorCallback = app.stream_instance.onerror.bind(app);

		const message = { msg: "hello jerry" };

		onMessageCallback({ data: JSON.stringify(message) });
		expect(app.stream_status.open).toBe(true);

		expect(app.event_callbacks).toEqual({});
		expect(app.pending_stream_messages).toEqual({});

		const close_stream_message = { msg: "close_stream" };
		onMessageCallback({ data: JSON.stringify(close_stream_message) });
		expect(app.stream_status.open).toBe(false);

		onErrorCallback({ data: JSON.stringify("404") });
		expect(app.stream_status.open).toBe(false);
	});
});