diff --git a/lab2/main_test.js b/lab2/main_test.js
index 5034468e..32ea43a8 100644
--- a/lab2/main_test.js
+++ b/lab2/main_test.js
@@ -1,6 +1,93 @@
-const test = require('node:test');
+const {mock, test} = require('node:test');
 const assert = require('assert');
+const fs = require('fs');
+
+mock.method(fs, 'readFile', (path, encoding, callback) => {
+    callback(null, 'John\nDoe');
+});
+
 const { Application, MailSystem } = require('./main');
 
 // TODO: write your tests here
-// Remember to use Stub, Mock, and Spy when necessary
\ No newline at end of file
+// Remember to use Stub, Mock, and Spy when necessary
+
+test('Test Application\'s getNames', async (t) => {
+    let myApp = new Application();
+    assert.deepEqual(await myApp.getNames(), [['John', 'Doe'], []]);
+});
+
+test('Test Application\'s getRandomPerson', async (t) => {
+    let myApp = new Application();
+    await new Promise((resolve) => { setTimeout(resolve, 1); });
+
+    const floor = t.mock.method(Math, 'floor');
+    const random = t.mock.method(Math, 'random');
+    let length = myApp.people.length;
+
+    for (let i = 0; i < length; i++) {
+        Math.random.mock.mockImplementation(() => i / length);
+        result = myApp.getRandomPerson();
+        assert.strictEqual(myApp.people.includes(result), true);
+        assert.strictEqual(result, myApp.people[i]);
+    }
+});
+
+test('Test Application\'s selectNextPerson', async (t) => {
+    myApp = new Application();
+    await new Promise((resolve) => { setTimeout(resolve, 1); });
+
+    for (let i = 0; i < myApp.people.length + 1; i++) {
+        count = myApp.selected.length;
+        result = myApp.selectNextPerson();
+
+        if (count < myApp.people.length) {
+            assert.strictEqual(myApp.selected.length, count + 1);
+            assert.strictEqual(myApp.selected.includes(result), true);
+        }
+        else
+        {
+            assert.strictEqual(myApp.selected.length, count);
+        }
+    }
+});
+
+test('Test Application\'s notifySelected', async (t) => {
+    myApp = new Application();
+    await new Promise((resolve) => { setTimeout(resolve, 1); });
+    myApp.selected = myApp.people;
+    myApp.mailSystem = new MailSystem();
+
+    const notifySelected = t.mock.method(myApp, 'notifySelected');
+    const send = t.mock.method(myApp.mailSystem, 'send');
+    const write = t.mock.method(myApp.mailSystem, 'write');
+
+    assert.strictEqual(notifySelected.mock.calls.length, 0);
+    assert.strictEqual(send.mock.calls.length, 0);
+    assert.strictEqual(write.mock.calls.length, 0);
+
+    myApp.notifySelected();
+    assert.strictEqual(notifySelected.mock.callCount(), 1);
+    assert.strictEqual(send.mock.calls.length, myApp.selected.length);
+    assert.strictEqual(write.mock.calls.length, myApp.selected.length);
+});
+
+test('Test MailSystem\'s write', (t) => {
+    myMailSystem = new MailSystem();
+    assert.strictEqual(myMailSystem.write('John'), 'Congrats, John!');
+});
+
+test('Test MailSystem\'s send', (t) => {
+    myMailSystem = new MailSystem();
+    const random = t.mock.method(Math, 'random');
+    assert.strictEqual(random.mock.callCount(), 0);
+
+    Math.random.mock.mockImplementation(() => 0.6);
+    result = myMailSystem.send(null, null);
+    assert.strictEqual(random.mock.callCount(), 1);
+    assert.strictEqual(result, true);
+
+    Math.random.mock.mockImplementation(() => 0.4);
+    result = myMailSystem.send(null, null);
+    assert.strictEqual(random.mock.callCount(), 2);
+    assert.strictEqual(result, false);
+});
\ No newline at end of file