diff --git a/lab2/README.md b/lab2/README.md
deleted file mode 100644
index 60a9c805..00000000
--- a/lab2/README.md
+++ /dev/null
@@ -1,22 +0,0 @@
-# Lab2
-
-## Introduction
-
-In this lab, you will write unit tests for functions implemented in `main.js`. You can learn how to use classes and functions in it by uncommenting the code in it. (But remember don't commit them on GitHub)
-
-## Requirement
-
-1. Write test cases in `main_test.js` and achieve 100% code coverage. Remember to use Mock, Spy, or Stub when necessary, you need to at least use one of them in your test cases. (100%)
-
-You can run `validate.sh` in your local to test if you satisfy the requirements.
-
-Please note that you must not alter files other than `main_test.js`. You will get 0 points if
-
-1. you modify other files to achieve requirements.
-2. you can't pass all CI on your PR.
-
-## Submission
-
-You need to open a pull request to your branch (e.g. 311XXXXXX, your student number) and contain the code that satisfies the abovementioned requirements.
-
-Moreover, please submit the URL of your PR to E3. Your submission will only be accepted when you present at both places.
diff --git a/lab2/main.js b/lab2/main.js
deleted file mode 100644
index 2e159e75..00000000
--- a/lab2/main.js
+++ /dev/null
@@ -1,81 +0,0 @@
-const fs = require('fs');
-const util = require('util');
-const readFile = util.promisify(fs.readFile);
-
-class MailSystem {
-    write(name) {
-        console.log('--write mail for ' + name + '--');
-        const context = 'Congrats, ' + name + '!';
-        return context;
-    }
-
-    send(name, context) {
-        console.log('--send mail to ' + name + '--');
-        // Interact with mail system and send mail
-        // random success or failure
-        const success = Math.random() > 0.5;
-        if (success) {
-            console.log('mail sent');
-        } else {
-            console.log('mail failed');
-        }
-        return success;
-    }
-}
-
-class Application {
-    constructor() {
-        this.people = [];
-        this.selected = [];
-        this.mailSystem = new MailSystem();
-        this.getNames().then(([people, selected]) => {
-            this.people = people;
-            this.selected = selected;
-        });
-    }
-
-    async getNames() {
-        const data = await readFile('name_list.txt', 'utf8');
-        const people = data.split('\n');
-        const selected = [];
-        return [people, selected];
-    }
-
-    getRandomPerson() {
-        const i = Math.floor(Math.random() * this.people.length);
-        return this.people[i];
-    }
-
-    selectNextPerson() {
-        console.log('--select next person--');
-        if (this.people.length === this.selected.length) {
-            console.log('all selected');
-            return null;
-        }
-        let person = this.getRandomPerson();
-        while (this.selected.includes(person)) {
-            person = this.getRandomPerson();
-        }
-        this.selected.push(person);
-        return person;
-    }
-
-    notifySelected() {
-        console.log('--notify selected--');
-        for (const x of this.selected) {
-            const context = this.mailSystem.write(x);
-            this.mailSystem.send(x, context);
-        }
-    }
-}
-
-// const app = new Application();
-// app.selectNextPerson();
-// app.selectNextPerson();
-// app.selectNextPerson();
-// app.notifySelected();
-
-module.exports = {
-    Application,
-    MailSystem,
-};
\ No newline at end of file
diff --git a/lab2/main_test.js b/lab2/main_test.js
deleted file mode 100644
index 5034468e..00000000
--- a/lab2/main_test.js
+++ /dev/null
@@ -1,6 +0,0 @@
-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
diff --git a/lab2/validate.sh b/lab2/validate.sh
deleted file mode 100755
index 13b53ed8..00000000
--- a/lab2/validate.sh
+++ /dev/null
@@ -1,38 +0,0 @@
-#!/bin/bash
-
-# Check for unwanted files
-for file in *; do
-  if [[ $file != "main.js" && $file != "main_test.js" && $file != "README.md" && $file != "validate.sh" ]]; then
-    echo "[!] Unwanted file detected: $file."
-    exit 1
-  fi
-done
-
-node=$(which node)
-test_path="${BASH_SOURCE[0]}"
-solution_path="$(realpath .)"
-tmp_dir=$(mktemp -d -t lab2-XXXXXXXXXX)
-
-cd $tmp_dir
-
-rm -rf *
-cp $solution_path/*.js .
-result=$($"node" --test --experimental-test-coverage) ; ret=$?
-if [ $ret -ne 0 ] ; then
-  echo "[!] testing fails"
-  exit 1
-else
-  coverage=$(echo "$result" | grep 'all files' | awk -F '|' '{print $2}' | sed 's/ //g')
-  if (( $(echo "$coverage < 100" | bc -l) )); then
-    echo "[!] Coverage is only $coverage%"
-    exit 1
-  else
-    echo "[V] Coverage is 100%"
-  fi
-fi
-
-rm -rf $tmp_dir
-
-exit 0
-
-# vim: set fenc=utf8 ff=unix et sw=2 ts=2 sts=2:
\ No newline at end of file
diff --git a/lab3/main_test.js b/lab3/main_test.js
index 096fd421..2ef844ec 100644
--- a/lab3/main_test.js
+++ b/lab3/main_test.js
@@ -3,3 +3,4 @@ const assert = require('assert');
 const { Calculator } = require('./main');
 
 // TODO: write your tests here
+});