index.test.ts

__test__/index.test.ts

@@ -0,0 +1,49 @@
+/* eslint-disable @typescript-eslint/no-var-requires */
+import mongoose from "mongoose";
+import app from "../src/app";
+import "../src/workers";
+
+// Mock console.error and console.log
+console.error = jest.fn();
+console.log = jest.fn();
+
+// Mock mongoose.connect and app.listen
+jest.mock("mongoose", () => ({
+  set: jest.fn(),
+  connect: jest.fn()
+}));
+jest.mock("../src/app", () => ({
+  listen: jest.fn(),
+}));
+jest.mock("../src/config", () => ({
+  env: {
+    MONGODB_URL: "mocked-mongodb-url",
+    PORT: 3000,
+  },
+}));
+jest.mock("../src/workers");
+
+describe("main", () => {
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it("should connect to MongoDB and start the server", async () => {
+    await expect(require("../src/index").main()).resolves.not.toThrow()
+
+    expect(mongoose.set).toHaveBeenCalledWith("strictQuery", true);
+    expect(mongoose.connect).toHaveBeenCalledWith("mocked-mongodb-url");
+    expect(app.listen).toHaveBeenCalledWith(3000, expect.any(Function));
+    expect(console.error).not.toHaveBeenCalled();
+  });
+
+  it("should handle errors and log them", async () => {
+    const error = new Error("Connection failed")
+    mongoose.connect = jest.fn().mockRejectedValueOnce(error)
+    await expect(require("../src/index").main()).rejects.toThrow(error);
+
+    expect(mongoose.connect).toHaveBeenCalledWith("mocked-mongodb-url");
+    expect(app.listen).not.toHaveBeenCalled();
+    expect(console.log).not.toHaveBeenCalled();
+  });
+});

src/index.ts

@@ -10,7 +10,7 @@ main().catch((err) => {
   console.error(err);
 });
 
-async function main(): Promise<void> {
+export async function main(): Promise<void> {
   await mongoose.connect(env.MONGODB_URL);
   app.listen(env.PORT, () => {
     console.log(