Welcome back! In the previous lesson, you added a layer of security to your application by implementing user authentication with Bcrypt. Now, we will shift our focus toward ensuring the robustness of our ToDo application's core functionalities through unit testing. Testing is a critical step in the development process, as it helps you ensure that each piece of your application behaves as expected.

Unit testing is an indispensable practice in software development. By writing effective unit tests, you ensure the stability of individual components throughout the development lifecycle. This not only aids in identifying bugs early on but also prevents them from propagating into wider parts of the application.

In this lesson, you will learn how to implement unit tests using RSpec for the ToDo service in a Ruby on Rails application. We will start with understanding how unit tests can verify the behavior of your application's individual components. Specifically, you will write tests for the create and get_all methods of the TodoService class. Here's a brief look at what you'll be working on:

• Testing the create method to ensure it accurately creates a new ToDo item:

• Verifying that the get_all method correctly retrieves all ToDo items:

As you develop more complex features, robust testing practices give you the confidence that your application will behave as expected with every addition or change. Moreover, a well-tested application is easier to maintain and can adapt more readily to future enhancements. By mastering unit testing in Ruby on Rails, you fortify your development skill set and contribute to building more reliable software solutions.