test the web sockets

server/client.test.ts

@@ -0,0 +1,59 @@
+/// <reference lib="deno.ns" />
+import { assertEquals } from "jsr:@std/assert";
+
+const url = "ws://0.0.0.0:6969";
+
+function connect(): Promise<WebSocket> {
+	return new Promise((resolve, reject) => {
+		const socket = new WebSocket(url);
+		socket.onopen = () => resolve(socket);
+		socket.onerror = (e) => reject(e);
+	});
+}
+
+function nextMessage(socket: WebSocket): Promise<unknown> {
+	return new Promise((resolve, reject) => {
+		const onMessage = (e: MessageEvent) => {
+			socket.removeEventListener("message", onMessage);
+			try {
+				resolve(JSON.parse(e.data));
+			} catch {
+				resolve(e.data);
+			}
+		};
+		socket.addEventListener("message", onMessage);
+		socket.addEventListener("error", reject, { once: true });
+	});
+}
+
+function closeAndWait(socket: WebSocket): Promise<void> {
+	return new Promise((resolve) => {
+		if (socket.readyState === WebSocket.CLOSED) return resolve();
+		socket.onclose = () => resolve();
+		socket.close();
+	});
+}
+
+Deno.test("broadcasts a message from one client to another", async () => {
+	const a = await connect(); // 1
+	const b = await connect(); // 2
+
+	const received = await nextMessage(b);
+	assertEquals(received, "2 has joined!");
+
+	await closeAndWait(a);
+	await closeAndWait(b);
+});
+
+Deno.test("removes a client from broadcast after it disconnects", async () => {
+	// test are executed in a row so the ID will just increment
+	const a = await connect(); // 3
+	const b = await connect(); // 4
+
+	await closeAndWait(b);
+
+	const msg = await nextMessage(a);
+	assertEquals(msg, "4 has left!");
+
+	await closeAndWait(a);
+});