diff --git a/lab1/main_test.js b/lab1/main_test.js
index 74a716b4..6f310129 100644
--- a/lab1/main_test.js
+++ b/lab1/main_test.js
@@ -2,22 +2,69 @@ const test = require('node:test');
 const assert = require('assert');
 const { MyClass, Student } = require('./main');
 
-test("Test MyClass's addStudent", () => {
-    // TODO
-    throw new Error("Test not implemented");
+// Test MyClass addStudent functionality
+test('Test MyClass addStudent', () => {
+  const myClass = new MyClass();
+  const student = new Student();
+
+ //check if student is instance of Student
+ const notAStudent = 123
+ const notAStudentInstance = myClass.addStudent(notAStudent);
+ assert.strictEqual(notAStudentInstance, -1, "If it's not a Student instance, it should return -1.");
+
+ // push student to Student list
+ student.setName("Joy");
+ const addStudentResult = myClass.addStudent(student);
+ assert.strictEqual(myClass.students[0], student, "The student has not been added to the student list. Add success");
+
+ // return id
+ assert.strictEqual(addStudentResult, 0, "Id should be 0 or positive number.")
 });
 
-test("Test MyClass's getStudentById", () => {
-    // TODO
-    throw new Error("Test not implemented");
+// Test MyClass getStudentById functionality
+test('Test MyClass getStudentById', () => {
+  const myClass = new MyClass();
+  const student = new Student();
+  student.setName('Tiffany');
+  myClass.addStudent(student);
+  
+  // Id is negative number
+  assert.strictEqual(myClass.getStudentById(-1), null, "Id should not be negative number, otherwise it will return null");
+
+  // Id is not exist
+  assert.strictEqual(myClass.getStudentById(myClass.students.length+1), null,  "Id is not exist");
+
+  // student exist
+  assert.strictEqual(myClass.getStudentById(0), student, "return student object");
+
 });
 
-test("Test Student's setName", () => {
-    // TODO
-    throw new Error("Test not implemented");
+// Test Student setName functionality
+test('Test Student setName', () => {
+  const student1 = new Student();
+  const student2 = new Student();
+
+  // pass a value to setName that is a string type
+  student1.setName('Alice');
+  assert.strictEqual(student1.getName(), 'Alice', 'Student name set correctly');
+
+  // pass a value to setName that is not a string type
+  student2.setName(123);
+    assert.strictEqual(student2.getName(), '', "userName should be in type of a string value");
+
+  
 });
 
-test("Test Student's getName", () => {
-    // TODO
-    throw new Error("Test not implemented");
-});
\ No newline at end of file
+// Test Student getName functionality
+test('Test Student getName', () => {
+  const student = new Student();
+
+  // Test getting the name of a student without setting a name
+  assert.strictEqual(student.getName(), '', 'Student name should be an empty string if not set');
+
+  // Test after set a name to student can return name
+  student.setName('Bob');
+  assert.strictEqual(student.getName(), 'Bob', 'Student name retrieved correctly');
+
+  
+});
diff --git a/lab2/main_test.js b/lab2/main_test.js
index 5034468e..702d9523 100644
--- a/lab2/main_test.js
+++ b/lab2/main_test.js
@@ -1,6 +1,146 @@
 const test = require('node:test');
 const assert = require('assert');
+const fs = require('fs');
+const os = require('os');
+const path = require('path');
+
 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('should return a message context', () => {
+    const mailSystem = new MailSystem();
+    const name = 'John';
+
+    const context = mailSystem.write(name);
+    assert.strictEqual(context, 'Congrats, John!');
+
+  });
+
+test('should return true if mail is sent successfully', (t) => {
+    const mailSystem = new MailSystem();
+    const name = 'John';
+
+    // test send mail success return true
+	t.mock.method(Math,'random', () => 1);
+    is_send = mailSystem.send('Joy', "test mail");
+    assert.strictEqual(is_send, true);
+ 
+
+    // test send mail fail return false
+	t.mock.method(Math,'random', () => 0.4);
+    is_send = mailSystem.send('Joy', "test mail");
+    assert.strictEqual(is_send, false);
+
+  });
+ 
+
+
+
+
+test('should return name_list ', async()=>{
+
+    // Write mock name list to a temporary file
+    const nameListContent = 'Alice\nBob\nCharlie';
+    const tempFilePath = path.join('name_list.txt');
+    fs.writeFileSync(tempFilePath, nameListContent);
+
+    // Attach cleanup handler to the process exit event
+    process.on('exit', () => {
+        if (tempFilePath) {
+        // Clean up: Delete the temporary directory
+        fs.unlinkSync(tempFilePath);
+        }
+    });
+
+    // Instantiate Application class and call getNames with the temporary file path
+    const app = new Application();
+    const [people, selected] = await app.getNames(tempFilePath);
+
+    // Assert the results
+    assert.deepStrictEqual(people, ['Alice', 'Bob', 'Charlie']);
+    assert.deepStrictEqual(selected, []);
+
+});
+
+    
+test('should return null if all people are selected', async (t) => {
+    const app = new Application();
+    app.people = ['Alice', 'Bob', 'Charlie'];
+    app.selected = ['Alice', 'Bob', 'Charlie'];
+    
+    const result = app.selectNextPerson();
+    assert.strictEqual(result, null);
+  });
+
+  //Test case for getRandomPerson() method
+test('should return a random person', () => {
+    // Stub Math.random() to return a fixed value
+    Math.random = () => 0.5; // Set Math.random() to always return 0.5
+    const randomNumber = Math.random();
+
+    // Create an instance of the Application class
+    const app = new Application();
+    app.people = ['Alice', 'Bob', 'Charlie'];
+    // Call the getRandomPerson() method
+    const randomPerson = app.getRandomPerson();
+
+    // Ensure that the random person is one of the people in the list
+    assert(app.people.includes(randomPerson));
+
+});
+
+test('should select and return a person who has not been selected yet', () => {
+    const app = new Application();
+    app.people = ['Alice', 'Bob', 'Charlie'];
+
+    let getRandomPersonCallCount = 0;
+    app.getRandomPerson = () => {
+        switch (getRandomPersonCallCount++) {
+            case 0:
+                return 'Alice';
+            case 1:
+                return 'Bob';
+            case 2:
+                return 'Charlie';
+        }
+    };
+
+    app.selected = ['Alice', 'Bob'];
+
+    const result = app.selectNextPerson();
+
+    assert.strictEqual(result, 'Charlie'); 
+    assert.strictEqual(getRandomPersonCallCount, 3); 
+});
+
+class MockMailSystem {
+    constructor() {
+        this.writeCallCount = 0;
+        this.sendCallCount = 0;
+    }
+
+    write() {
+        this.writeCallCount++;
+        return 'Message context';
+    }
+
+    send() {
+        this.sendCallCount++;
+        return true;
+    }
+}
+
+test('should call write and send methods of MailSystem for each selected person', () => {
+    const mailSystem = new MockMailSystem();
+
+    const app = new Application();
+    app.mailSystem = mailSystem;
+    app.selected = ['Alice', 'Bob', 'Charlie'];
+
+    app.notifySelected();
+
+    assert.strictEqual(mailSystem.writeCallCount, 3);
+    assert.strictEqual(mailSystem.sendCallCount, 3);
+
+
+});
+