Writing a Test Without Tools

Explore how to write basic automated tests for a pure email validation function without any testing tools. Learn to verify both valid and invalid cases manually and understand the challenges of scaling tests as complexity grows.

We'll cover the following...

The function we want to test
Writing a happy path test
Writing an unhappy path test
The need for tooling

The function we want to test

Here is the function we want to test:

function isEmail(email) {
  const regex = new RegExp(/^[^@\s]+@[^@\s.]+\.[^@.\s]+$/);
  return regex.test(email);
}

The function validates whether an email address is formatted correctly. The function has no dependencies and doesn’t mutate the email parameter passed into it, which means it is a pure function. Pure ...

1.Introduction

2.Getting Started with Jest

3.Using Matchers

4.Getting Started with React Testing Library

5.React Testing Library Queries

6.Firing Events

7.Mocking

8.Testing Different Types of Components

9.Appendix

Writing a Test Without Tools

The function we want to test