diff --git a/lab1/main_test.js b/lab1/main_test.js
index 74a716b4..2bb19a34 100644
--- a/lab1/main_test.js
+++ b/lab1/main_test.js
@@ -3,21 +3,58 @@ const assert = require('assert');
 const { MyClass, Student } = require('./main');
 
 test("Test MyClass's addStudent", () => {
-    // TODO
-    throw new Error("Test not implemented");
+    // Test adding a valid student
+    const myClass = new MyClass();
+    const student1 = new Student();
+    assert.strictEqual(myClass.addStudent(student1), 0);
+    assert.strictEqual(myClass.students.length, 1);
+    assert.strictEqual(myClass.students[0], student1);
+
+    // Test adding another valid student
+    const student2 = new Student();
+    assert.strictEqual(myClass.addStudent(student2), 1);
+    assert.strictEqual(myClass.students.length, 2);
+    assert.strictEqual(myClass.students[1], student2);
+
+    // Test adding an invalid student
+    assert.strictEqual(myClass.addStudent({}), -1);
+    assert.strictEqual(myClass.students.length, 2); // Should not add invalid student
 });
 
 test("Test MyClass's getStudentById", () => {
-    // TODO
-    throw new Error("Test not implemented");
+    // Test getting student by valid id
+    const myClass = new MyClass();
+    const student1 = new Student();
+    const student2 = new Student();
+
+    myClass.addStudent(student1);
+    myClass.addStudent(student2);
+
+    assert.strictEqual(myClass.getStudentById(0), student1);
+    assert.strictEqual(myClass.getStudentById(1), student2);
+
+    // Test getting student by invalid id
+    assert.strictEqual(myClass.getStudentById(-1), null);
+    assert.strictEqual(myClass.getStudentById(2), null);
 });
 
 test("Test Student's setName", () => {
-    // TODO
-    throw new Error("Test not implemented");
+    // Test setting valid name
+    const student = new Student();
+    student.setName("CHINA");
+    assert.strictEqual(student.name, "CHINA");
+
+    // Test setting invalid name
+    student.setName(8081);
+    assert.strictEqual(student.name, "CHINA"); // Should not change name if invalid
 });
 
 test("Test Student's getName", () => {
-    // TODO
-    throw new Error("Test not implemented");
-});
\ No newline at end of file
+    // Test getting name when name is not set
+    const student = new Student();
+    assert.strictEqual(student.getName(), "");
+
+    // Test getting name when name is set
+    student.setName("CUBA");
+    assert.strictEqual(student.getName(), "CUBA");
+});
diff --git a/lab2/main_test.js b/lab2/main_test.js
index 5034468e..1d09ee75 100644
--- a/lab2/main_test.js
+++ b/lab2/main_test.js
@@ -2,5 +2,46 @@ const test = require('node:test');
 const assert = require('assert');
 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
+test("Test Application's selectNextPerson", () => {
+    const app = new Application();
+    const initialSelectedLength = app.selected.length;
+    const selectedPerson = app.selectNextPerson();
+    assert.strictEqual(app.selected.length, initialSelectedLength + 1, "One person should be selected");
+});
+
+test("Test Application's notifySelected", () => {
+    const app = new Application();
+    const consoleSpy = jest.spyOn(console, 'log');
+    app.notifySelected();
+    expect(consoleSpy).toHaveBeenCalled();
+});
+
+test("Test MailSystem's write method", () => {
+    const mailSystem = new MailSystem();
+    const name = "John";
+    const context = mailSystem.write(name);
+    assert.strictEqual(context, `Congrats, ${name}!`, "Context should match expected");
+});
+
+test("Test MailSystem's send method", () => {
+    const mailSystem = new MailSystem();
+    const name = "John";
+    const context = "Test context";
+    const result = mailSystem.send(name, context);
+    assert(result === true || result === false, "send method should return a boolean");
+});
+
+test("Test Application's getRandomPerson", () => {
+    const app = new Application();
+    const getRandomPersonSpy = jest.spyOn(app, 'getRandomPerson');
+    app.getRandomPerson();
+    expect(getRandomPersonSpy).toHaveBeenCalled();
+});
+
+test("Test Application's getRandomPerson with stubbed getNames method", () => {
+    const app = new Application();
+    const stubbedNames = ['John', 'Jane', 'Doe'];
+    app.getNames = jest.fn().mockResolvedValue([stubbedNames, []]);
+    const randomPerson = app.getRandomPerson();
+    expect(stubbedNames).toContain(randomPerson);
+});