diff --git a/lab2/main_test.js b/lab2/main_test.js
index 5034468e..d0d0a4d4 100644
--- a/lab2/main_test.js
+++ b/lab2/main_test.js
@@ -2,5 +2,123 @@ 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
+/*
+    function coverage testing:
+    - MailSystem
+        - write
+        - send
+    - Application
+        - getNames
+        - getRandomPerson
+        - selectNextPerson
+        - notifySelected
+*/
+
+// MailSystem test
+test('MailSystem write test', (t) => {
+    const mail = new MailSystem();
+    const result = mail.write('Test');
+    assert.equal(result, 'Congrats, Test!');
+});
+
+// Test Stub
+test('MailSystem send test', (t) => {
+    const mail = new MailSystem();
+    const originalRandom = Math.random;
+    
+    // Test success case
+    Math.random = () => 1;
+    assert.equal(mail.send('Test', 'content'), true);
+    
+    // Test failure case
+    Math.random = () => 0;
+    assert.equal(mail.send('Test', 'content'), false);
+    
+    Math.random = originalRandom;
+});
+
+// Application tests
+test('Application initialization test', async (t) => {
+    // 準備測試檔案
+    fs.writeFileSync('name_list.txt', 'Test1\nTest2\nTest3');
+  
+    try {
+      const app = new Application();
+      await new Promise(resolve => setTimeout(resolve, 100)); // 等待初始化完成
+  
+      assert(Array.isArray(app.people));
+      assert(Array.isArray(app.selected));
+      assert.equal(app.people.length, 3);
+      assert.equal(app.selected.length, 0);
+    } finally {
+      // 清理測試檔案
+      fs.unlinkSync('name_list.txt');
+    }
+});
+
+
+test('Application selectNextPerson test', async (t) => {
+    // 準備測試檔案
+    fs.writeFileSync('name_list.txt', 'Test1\nTest2\nTest3');
+  
+    try {
+        const app = new Application();
+        await new Promise(resolve => setTimeout(resolve, 100)); // 等待初始化完成
+
+        const person1 = app.selectNextPerson();
+        assert(app.people.includes(person1));
+        assert.equal(app.selected.length, 1);
+
+        const person2 = app.selectNextPerson();
+        assert(app.people.includes(person2));
+        assert.equal(app.selected.length, 2);
+        assert.notEqual(person1, person2);
+
+        const person3 = app.selectNextPerson();
+        assert(app.people.includes(person3));
+        assert.equal(app.selected.length, 3);
+
+        // 當所有人都被選中後，應該返回 null
+        const person4 = app.selectNextPerson();
+        assert.equal(person4, null);
+    } finally {
+        // 清理測試檔案
+        fs.unlinkSync('name_list.txt');
+    }
+});
+
+
+// Mock Object 
+test('Application notifySelected test', async (t) => {
+    // 準備測試檔案
+    fs.writeFileSync('name_list.txt', 'Test1\nTest2');
+
+    try {
+        const app = new Application();
+        await new Promise(resolve => setTimeout(resolve, 100)); // 等待初始化完成
+        
+        app.selectNextPerson(); // 選擇第一個人
+        app.selectNextPerson(); // 選擇第二個人
+
+        // Mock MailSystem methods
+        let writeCount = 0;
+        let sendCount = 0;
+        app.mailSystem.write = (name) => {
+            writeCount++;
+            return `Congrats, ${name}!`;
+        };
+        app.mailSystem.send = (name, context) => {
+            sendCount++;
+            return true;
+        };
+        
+        app.notifySelected();
+        assert.equal(writeCount, 2);
+        assert.equal(sendCount, 2);
+    } finally {
+        // 清理測試檔案
+        fs.unlinkSync('name_list.txt');
+    }
+});
+
+
diff --git a/lab8/solve.py b/lab8/solve.py
index 9ab3ee2f..f8089f09 100755
--- a/lab8/solve.py
+++ b/lab8/solve.py
@@ -1,11 +1,47 @@
 #!/usr/bin/env python3
 
-import angr,sys
+def solve():
+    # 我們需要找到滿足以下條件的 8 個字元：
+    # 1. (input[0] ^ input[1]) == 0x55
+    # 2. (input[2] + input[3]) == 200
+    # 3. (input[4] * 3) == input[5]
+    # 4. (input[6] - input[7]) == 1
+    # 5. (input[1] + input[2] - input[3]) == 50
+    # 6. (input[5] ^ input[6]) == 0x2A
+    
+    # 嘗試所有可能的值
+    for a in range(32, 127):  # input[0]
+        for b in range(32, 127):  # input[1]
+            if (a ^ b) != 0x55:
+                continue
+                
+            for c in range(32, 127):  # input[2]
+                for d in range(32, 127):  # input[3]
+                    if (c + d) != 200:
+                        continue
+                    
+                    if (b + c - d) != 50:
+                        continue
+                    
+                    for e in range(32, 127):  # input[4]
+                        f = e * 3  # input[5]
+                        if f < 32 or f > 126:
+                            continue
+                            
+                        for g in range(32, 127):  # input[6]
+                            if (f ^ g) != 0x2A:
+                                continue
+                                
+                            h = g - 1  # input[7]
+                            if h < 32 or h > 126:
+                                continue
+                            
+                            # 所有條件都滿足，輸出密鑰
+                            key = chr(a) + chr(b) + chr(c) + chr(d) + chr(e) + chr(f) + chr(g) + chr(h)
+                            return key
+    
+    return "No solution found!"
 
-def main():
-    secret_key = b""
-    sys.stdout.buffer.write(secret_key)
-
-
-if __name__ == '__main__':
-    main()
+if __name__ == "__main__":
+    key = solve()
+    print(key)