Added descriptive step by step approach to configuring the development enviroment

tests/db.test.js

@@ -0,0 +1,87 @@
+const test = require('node:test');
+const assert = require('node:assert');
+const Database = require('better-sqlite3');
+
+// Helper function to initialize throwaway in-memory database
+function setupInMemoryDb() {
+    const db = new Database(':memory:');
+    db.exec(`
+        CREATE TABLE tasks (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            title TEXT NOT NULL,
+            description TEXT,
+            due_date TEXT NOT NULL,
+            topic TEXT NOT NULL,
+            status TEXT CHECK(status IN ('Todo','In-Progress','Complete')) NOT NULL DEFAULT 'Todo',
+            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+            is_archived BOOLEAN NOT NULL DEFAULT 0
+        );
+    `);
+    return db;
+}
+
+// Helper to compute overdue dynamically
+function computeIsOverdue(dueDateStr, status) {
+    if (status === 'Complete') return false;
+    const today = new Date().toISOString().split('T')[0];
+    return dueDateStr < today;
+}
+
+test('1. Task Creation and Retrieval on throwaway in-memory SQLite database', () => {
+    const db = setupInMemoryDb();
+    
+    const stmt = db.prepare(`
+        INSERT INTO tasks (title, description, due_date, topic, status)
+        VALUES (?, ?, ?, ?, ?)
+    `);
+    const info = stmt.run('Complete Lab Report', 'Detail dynamic overdue rules', '2026-12-31', 'University', 'Todo');
+    
+    assert.strictEqual(info.changes, 1);
+    
+    const task = db.prepare('SELECT * FROM tasks WHERE id = ?').get(info.lastInsertRowid);
+    assert.strictEqual(task.title, 'Complete Lab Report');
+    assert.strictEqual(task.topic, 'University');
+    assert.strictEqual(task.status, 'Todo');
+    assert.strictEqual(task.is_archived, 0);
+});
+
+test('2. Dynamic Overdue Calculation Rule (read-time comparison)', () => {
+    const pastDate = '2020-01-01';
+    const futureDate = '2099-12-31';
+
+    // Past due date with 'Todo' status must be overdue
+    assert.strictEqual(computeIsOverdue(pastDate, 'Todo'), true);
+    
+    // Past due date with 'In-Progress' status must be overdue
+    assert.strictEqual(computeIsOverdue(pastDate, 'In-Progress'), true);
+    
+    // Past due date with 'Complete' status must NOT be overdue
+    assert.strictEqual(computeIsOverdue(pastDate, 'Complete'), false);
+    
+    // Future due date must NOT be overdue
+    assert.strictEqual(computeIsOverdue(futureDate, 'Todo'), false);
+});
+
+test('3. Task Archiving (Soft-deletion) and Unarchiving Verification', () => {
+    const db = setupInMemoryDb();
+    
+    // Insert task
+    const info = db.prepare(`
+        INSERT INTO tasks (title, due_date, topic) VALUES ('Archive Test Task', '2026-08-01', 'Testing')
+    `).run();
+    const taskId = info.lastInsertRowid;
+
+    // Archive task (is_archived = 1)
+    db.prepare('UPDATE tasks SET is_archived = 1 WHERE id = ?').run(taskId);
+    let task = db.prepare('SELECT * FROM tasks WHERE id = ?').get(taskId);
+    assert.strictEqual(task.is_archived, 1);
+
+    // Active tasks query must not return archived task
+    const activeTasks = db.prepare('SELECT * FROM tasks WHERE is_archived = 0').all();
+    assert.strictEqual(activeTasks.length, 0);
+
+    // Unarchive task (is_archived = 0)
+    db.prepare('UPDATE tasks SET is_archived = 0 WHERE id = ?').run(taskId);
+    task = db.prepare('SELECT * FROM tasks WHERE id = ?').get(taskId);
+    assert.strictEqual(task.is_archived, 0);
+});