test: implement tests using vitest framework

test/bedrock.test.js

@@ -0,0 +1,117 @@
+import dgram from "node:dgram";
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import { pingBedrock } from "../lib/bedrock.js";
+
+vi.mock("node:dgram");
+
+describe("bedrock.js", () => {
+	let mockSocket;
+
+	beforeEach(() => {
+		// A store for event handlers, closed over by the mockSocket.
+		const handlers = {};
+
+		// Create a stateful mock socket to simulate EventEmitter.
+		mockSocket = {
+			send: vi.fn(),
+			close: vi.fn(),
+			on: vi.fn((event, handler) => {
+				handlers[event] = handler;
+			}),
+			emit: vi.fn((event, ...args) => {
+				if (handlers[event]) {
+					handlers[event](...args);
+				}
+			}),
+		};
+
+		dgram.createSocket = vi.fn().mockReturnValue(mockSocket);
+		vi.useFakeTimers();
+	});
+
+	afterEach(() => {
+		vi.restoreAllMocks();
+		vi.useRealTimers();
+	});
+
+	it("should ping a server and parse MOTD", async () => {
+		const host = "play.example.com";
+		const options = { port: 25565, timeout: 10000 };
+		const pingPromise = pingBedrock(host, options);
+
+		const motd =
+			"MCPE;§l§bＯａｓｙｓ§fＰＥ;0;1337;1096;1999;-37530542056358113;oasys-pe.ru;Adventure;1";
+		const mockPongPacket = createMockPongPacket(motd);
+
+		mockSocket.emit("message", mockPongPacket);
+
+		const result = await pingPromise;
+
+		expect(dgram.createSocket).toHaveBeenCalledWith("udp4");
+		expect(mockSocket.send).toHaveBeenCalledWith(
+			expect.any(Buffer),
+			0,
+			33,
+			options.port,
+			host
+		);
+		expect(mockSocket.close).toHaveBeenCalled();
+		expect(result).toEqual({
+			edition: "MCPE",
+			name: "§l§bＯａｓｙｓ§fＰＥ",
+			version: { protocolVersion: 0, minecraftVersion: "1337" },
+			players: { online: 1096, max: 1999 },
+			serverId: "-37530542056358113",
+			mapName: "oasys-pe.ru",
+			gameMode: "Adventure",
+		});
+	});
+
+	describe("errors", () => {
+		it("should throw an error if host is not provided", () => {
+			expect(() => pingBedrock(null)).toThrow("Host argument is not provided");
+		});
+
+		it("should reject on socket timeout", async () => {
+			const pingPromise = pingBedrock("play.example.com", { timeout: 1000 });
+
+			vi.advanceTimersByTime(1000);
+
+			await expect(pingPromise).rejects.toThrow("Socket timeout");
+			expect(mockSocket.close).toHaveBeenCalled();
+		});
+
+		it("should reject on a generic socket error", async () => {
+			const pingPromise = pingBedrock("play.example.com");
+
+			// Simulate a DNS or network error by emitting it.
+			mockSocket.emit("error", new Error("EHOSTUNREACH"));
+
+			await expect(pingPromise).rejects.toThrow("EHOSTUNREACH");
+		});
+
+		it("should only reject once, even if multiple errors occur", async () => {
+			const pingPromise = pingBedrock("play.example.com");
+
+			// Fire a socket error first.
+			mockSocket.emit("error", new Error("First error"));
+
+			// Then, try to trigger another error by sending a bad message.
+			mockSocket.emit("message", Buffer.alloc(0));
+
+			await expect(pingPromise).rejects.toThrow("First error");
+			expect(mockSocket.close).toHaveBeenCalledTimes(1);
+		});
+	});
+});
+
+function createMockPongPacket(motd) {
+	const motdBuffer = Buffer.from(motd, "utf-8");
+	const packet = Buffer.alloc(35 + motdBuffer.length);
+	packet.writeUInt8(0x1c, 0);
+	packet.writeBigInt64LE(BigInt(Date.now()), 1);
+	Buffer.from("00ffff00fefefefefdfdfdfd12345678", "hex").copy(packet, 17);
+	packet.writeUInt16BE(motdBuffer.length, 33);
+	motdBuffer.copy(packet, 35);
+	return packet;
+}