diff --git a/lab2/main_test.js b/lab2/main_test.js
index 5034468e..73a967a3 100644
--- a/lab2/main_test.js
+++ b/lab2/main_test.js
@@ -1,6 +1,181 @@
 const test = require('node:test');
 const assert = require('assert');
 const { Application, MailSystem } = require('./main');
+const fs = require('fs');
+const path = require('path');
+const util = require('util');
 
-// TODO: write your tests here
-// Remember to use Stub, Mock, and Spy when necessary
\ No newline at end of file
+const writeFile = util.promisify(fs.writeFile);
+const unlink = util.promisify(fs.unlink);
+
+test("Test Mail System's write", () => {
+
+    const mailSystem = new MailSystem();
+    const context = mailSystem.write('Hong');
+    assert.strictEqual(context, 'Congrats, Hong!');
+});
+
+test("Test Mail System's send", () => {
+
+    const mailSystem = new MailSystem();
+    const orgRandom = Math.random;
+    Math.random = () => 0.6;
+    const success = mailSystem.send('Hong', 'Congrats, Hong!');
+    assert.strictEqual(success, true);
+    Math.random = () => 0.4;
+    const fail = mailSystem.send('Hong', 'Congrats, Hong!');
+    assert.strictEqual(fail, false);
+    Math.random = orgRandom;
+});
+
+//因為需要等待getNames(異步函數async)所以需要用await等待結果，因此這裡需要用async
+test("Test Application's getNames", async() => {
+    const mockData = 'Hong\nAlbert\nIan';
+    const filePath = path.join(__dirname, 'name_list.txt');
+
+    // Write the mock data to a file
+    await writeFile(filePath, mockData);
+
+    try {
+        const app = new Application();
+        const [names, selected] = await app.getNames();
+
+        assert.deepStrictEqual(names, ['Hong', 'Albert', 'Ian']);
+        assert.deepStrictEqual(selected, []);
+    } finally {
+        // Delete the file
+        await unlink(filePath);
+    }
+});
+
+test("Test Application's getRandomPerson", async() => {
+    const mockData = 'Hong\nAlbert\nIan';
+    const filePath = path.join(__dirname, 'name_list.txt');
+    const orgRandom = Math.random;
+    // Write the mock data to a file
+    await writeFile(filePath, mockData);
+
+    try {
+        const app = new Application();
+        const [names, selected] = await app.getNames();
+
+        assert.deepStrictEqual(names, ['Hong', 'Albert', 'Ian']);
+        assert.deepStrictEqual(selected, []);
+
+        Math.random = () => 0.1;
+        var person = app.getRandomPerson();
+        assert.strictEqual(person, 'Hong');
+
+        Math.random = () => 0.5;
+        var person = app.getRandomPerson();
+        assert.strictEqual(person, 'Albert');
+
+        Math.random = () => 0.9;
+        var person = app.getRandomPerson();
+        assert.strictEqual(person, 'Ian');
+        
+    } finally {
+        // Delete the file
+        Math.random = orgRandom;
+        await unlink(filePath);
+    }
+});
+test("Test Application's selectNextPerson", async() => {
+    const mockData = 'Hong\nAlbert\nIan';
+    const filePath = path.join(__dirname, 'name_list.txt');
+    await writeFile(filePath, mockData);
+
+    try {
+        let app = new Application();
+        let [names, selected] = await app.getNames();
+
+        assert.deepStrictEqual(names, ['Hong', 'Albert', 'Ian']);
+        assert.deepStrictEqual(selected, []);
+        const orgGetRandomPerson = app.getRandomPerson;
+        app.getRandomPerson = () => 'Hong';
+        var person = app.selectNextPerson();
+        assert.strictEqual(person, 'Hong');
+        assert.deepStrictEqual(app.selected, ['Hong']);
+
+        app.getRandomPerson = () => 'Albert';
+        person = app.selectNextPerson();
+        assert.strictEqual(person, 'Albert');
+        assert.deepStrictEqual(app.selected, ['Hong', 'Albert']);
+
+        app.getRandomPerson = () => 'Ian';
+        person = app.selectNextPerson();
+        assert.strictEqual(person, 'Ian');
+        assert.deepStrictEqual(app.selected, ['Hong', 'Albert', 'Ian']);
+
+        //確認name的lenth == selected的lenth
+        app.getRandomPerson = orgGetRandomPerson;
+        assert.strictEqual(app.people.length, app.selected.length);
+        assert.strictEqual(app.selectNextPerson(), null);
+        
+        
+        //測試while情況
+        let cnt = 0;
+        app.getRandomPerson = () => {
+            
+            if (cnt % 3 === 0) {
+                cnt++;
+                return 'Hong';
+            } else if (cnt % 3 === 1){
+                cnt++;
+                return 'Albert';
+            } else {
+                return 'Ian';
+            }
+            
+        };
+        app.selected = ['Hong', 'Albert'];
+        assert.strictEqual(app.selectNextPerson(), 'Ian');
+        assert.deepStrictEqual(app.selected, ['Hong', 'Albert', 'Ian']); 
+        
+    } finally {
+        // Delete the file
+        await unlink(filePath);
+    }
+});
+
+test("Test Application's notifySelected", async () => {
+    const mockData = 'Hong\nAlbert';
+    const filePath = path.join(__dirname, 'name_list.txt');
+    await writeFile(filePath, mockData);
+    try {
+        let app = new Application();
+        let [names, selected] = await app.getNames();
+
+        assert.deepStrictEqual(names, ['Hong', 'Albert']);
+        assert.deepStrictEqual(selected, []);
+        const orgGetRandomPerson = app.getRandomPerson;
+        app.getRandomPerson = () => 'Hong';
+        var person = app.selectNextPerson();
+        assert.strictEqual(person, 'Hong');
+        assert.deepStrictEqual(app.selected, ['Hong']);
+
+        app.getRandomPerson = () => 'Albert';
+        person = app.selectNextPerson();
+        assert.strictEqual(person, 'Albert');
+        assert.deepStrictEqual(app.selected, ['Hong', 'Albert']);
+
+        test.mock.method(app.mailSystem, 'write', (name) => "Congrats, " + name + "!");
+        test.mock.method(app.mailSystem, 'send', () => true);
+        app.notifySelected();
+        assert.strictEqual(app.mailSystem.write.mock.calls.length, 2);
+        assert.strictEqual(app.mailSystem.send.mock.calls.length, 2);
+
+        let call = app.mailSystem.write.mock.calls[0];
+        assert.deepStrictEqual(call.arguments, ["Hong"]);
+        assert.deepStrictEqual(call.result, "Congrats, Hong!");
+        assert.deepStrictEqual(call.error, undefined);
+
+        call = app.mailSystem.write.mock.calls[1];
+        assert.deepStrictEqual(call.arguments, ["Albert"]);
+        assert.deepStrictEqual(call.result, "Congrats, Albert!");
+        assert.deepStrictEqual(call.error, undefined);
+        app.getRandomPerson = orgGetRandomPerson;
+    } finally {
+        await unlink(filePath);
+    }
+});
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