Test database setup and teardown in Express - Mini Project: Build & Apply

Test database setup and teardown

📖 Scenario: You are building an Express.js application that uses a test database. To keep tests reliable, you need to set up the test database before tests run and clean it up after tests finish.This project guides you to write code that connects to a test database, configures setup and teardown functions, and integrates them with your test framework.

🎯 Goal: Create an Express.js test setup that connects to a test database before tests and disconnects after tests, ensuring a clean environment for each test run.

📋 What You'll Learn

Create a connection to a test database using a variable named testDb

Add a configuration variable testDbUrl with the test database URL string

Write an async function setupTestDb that connects to testDbUrl

Write an async function teardownTestDb that disconnects testDb

💡 Why This Matters

🌍 Real World

In real projects, tests need a clean database environment. Setting up and tearing down a test database ensures tests do not interfere with each other and results are reliable.

💼 Career

Knowing how to manage test databases is important for backend developers and QA engineers to write maintainable and trustworthy automated tests.

1

Create the test database connection variable

Create a variable called testDb and assign it the result of calling require('some-db-library').createConnection().

Express

// Create the testDb connection variable
// Your code here

Need a hint?

Use require('some-db-library').createConnection() to create the connection.

2

Add the test database URL configuration

Add a constant called testDbUrl and set it to the string 'mongodb://localhost:27017/testdb'.

Express

const testDb = require('some-db-library').createConnection();

// Add the testDbUrl constant with the test database URL string
// Your code here

Need a hint?

Use a string with the exact URL 'mongodb://localhost:27017/testdb'.

3

Write the setup function to connect to the test database

Write an async function called setupTestDb that calls await testDb.connect(testDbUrl) inside its body.

Express

const testDb = require('some-db-library').createConnection();
const testDbUrl = 'mongodb://localhost:27017/testdb';

// Write async function setupTestDb to connect testDb to testDbUrl
// Your code here

Need a hint?

Define an async function and use await testDb.connect(testDbUrl) inside.

4

Write the teardown function to disconnect the test database

Write an async function called teardownTestDb that calls await testDb.disconnect() inside its body.

Express

const testDb = require('some-db-library').createConnection();
const testDbUrl = 'mongodb://localhost:27017/testdb';

async function setupTestDb() {
    await testDb.connect(testDbUrl);
}

// Write async function teardownTestDb to disconnect testDb
// Your code here

Need a hint?

Define an async function and use await testDb.disconnect() inside.