diff --git a/lab1/main_test.js b/lab1/main_test.js
index 74a716b4..4b5e9b54 100644
--- a/lab1/main_test.js
+++ b/lab1/main_test.js
@@ -1,23 +1,41 @@
-const test = require('node:test');
-const assert = require('assert');
-const { MyClass, Student } = require('./main');
+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");
+    const myClass = new MyClass();
+    assert.strictEqual(myClass.addStudent('Not a student'), -1);
+    const student = new Student();
+    for (let i = 0; i < 3; i++) {
+        const student = new Student();
+        assert.strictEqual(myClass.addStudent(student), i);
+    }
 });
 
 test("Test MyClass's getStudentById", () => {
-    // TODO
-    throw new Error("Test not implemented");
+    const myClass = new MyClass();
+    assert.strictEqual(myClass.getStudentById(-1), null);
+    for (let i = 0; i < 3; i++) {
+        const student = new Student();
+        myClass.addStudent(student);
+        assert.strictEqual(myClass.getStudentById(i), student);
+    }
+    assert.strictEqual(myClass.getStudentById(3), null);
 });
 
 test("Test Student's setName", () => {
-    // TODO
-    throw new Error("Test not implemented");
+    const student = new Student();
+    student.setName(123);
+    assert.strictEqual(student.getName(), '');
+    const name = "Pudding0803";
+    student.setName(name);
+    assert.strictEqual(student.getName(), name);
 });
 
 test("Test Student's getName", () => {
-    // TODO
-    throw new Error("Test not implemented");
-});
\ No newline at end of file
+    const student = new Student();
+    assert.strictEqual(student.getName(), '');
+    const name = "Pudding0803";
+    student.setName(name);
+    assert.strictEqual(student.getName(), name);
+});
diff --git a/lab2/main.js b/lab2/main.js
index 2e159e75..17efcce7 100644
--- a/lab2/main.js
+++ b/lab2/main.js
@@ -53,6 +53,7 @@ class Application {
             return null;
         }
         let person = this.getRandomPerson();
+        console.log(person);
         while (this.selected.includes(person)) {
             person = this.getRandomPerson();
         }
diff --git a/lab2/main_test.js b/lab2/main_test.js
index 5034468e..43255616 100644
--- a/lab2/main_test.js
+++ b/lab2/main_test.js
@@ -1,6 +1,79 @@
-const test = require('node:test');
-const assert = require('assert');
-const { Application, MailSystem } = require('./main');
+const { test, mock } = require("node:test");
+const assert = require("assert");
+const { Application, MailSystem } = require("./main");
+const fs = require('fs');
+const util = require('util');
+const writeFile = util.promisify(fs.writeFile);
+const unlinkFile = util.promisify(fs.unlink);
 
-// TODO: write your tests here
-// Remember to use Stub, Mock, and Spy when necessary
\ No newline at end of file
+const MATH_RANDOM = Math.random;
+const FILE_NAME = "name_list.txt";
+const CONTENT = "name 0\nname 1\nname 2"
+
+test("Test Mail's write", () => {
+    const mailSystem = new MailSystem();
+    assert.strictEqual(
+        mailSystem.write("Pudding0803"),
+        "Congrats, Pudding0803!"
+    );
+});
+
+test("Test Mail's send", () => {
+    const mailSystem = new MailSystem();
+    Math.random = mock.fn(() => 0.6);
+    assert.strictEqual(mailSystem.send("Pudding0803", "Hello, world!"), true);
+    Math.random = mock.fn(() => 0.5);
+    assert.strictEqual(mailSystem.send("Pudding0803", "Hello, world!"), false);
+    Math.random = MATH_RANDOM;
+});
+
+test("Test Application's getNames", async () => {
+    fs.writeFile(FILE_NAME, CONTENT, () => {});
+    const app = new Application();
+    assert.deepStrictEqual(
+        await app.getNames(),
+        [["name 0", "name 1", "name 2"], []]
+    );
+    fs.unlink(FILE_NAME, () => {});
+});
+
+test("Test Application's getRandomPerson", async () => {
+    fs.writeFile(FILE_NAME, CONTENT, () => {});
+    const app = new Application();
+    await app.getNames();
+    Math.random = mock.fn(() => 0);
+    assert.strictEqual(app.getRandomPerson(), "name 0");
+    Math.random = mock.fn(() => 0.99);
+    assert.strictEqual(app.getRandomPerson(), "name 2");
+    Math.random = MATH_RANDOM;
+    fs.unlink(FILE_NAME, () => {});
+});
+
+test("Test Application's selectNextPerson", async () => {
+    fs.writeFile(FILE_NAME, CONTENT, () => {});
+    const app = new Application();
+    await app.getNames();
+    Math.random = mock.fn(() => 0);
+    assert.strictEqual(app.selectNextPerson(), "name 0");
+    Math.random = mock.fn(() => 0.4);
+    assert.strictEqual(app.selectNextPerson(), "name 1");
+    Math.random = MATH_RANDOM;
+    assert.strictEqual(app.selectNextPerson(), "name 2");
+    assert.strictEqual(app.selectNextPerson(), null);
+    fs.unlink(FILE_NAME, () => {});
+});
+
+test("Test Application's notifySelected", async () => {
+    fs.writeFile(FILE_NAME, CONTENT, () => {});
+    const app = new Application();
+    await app.getNames();
+    app.mailSystem.write = mock.fn((name) => name);
+    app.mailSystem.send = mock.fn((name, context) => true);
+    app.selectNextPerson();
+    app.selectNextPerson();
+    app.notifySelected();
+    assert.strictEqual(app.mailSystem.write.mock.calls.length, 2);
+    assert.strictEqual(app.mailSystem.send.mock.calls.length, 2);
+    Math.random = MATH_RANDOM;
+    fs.unlink(FILE_NAME, () => {});
+});