Video Notes

Introduction

In this guide, we’ll walk through how to create a unit test in a Laravel project using Pest, a modern testing framework built on top of PHPUnit.

If you’re familiar with PHPUnit, Pest provides a cleaner and more expressive syntax while still leveraging the same underlying functionality.

What Is Unit Testing?

Before jumping into the steps, it’s helpful to understand what unit testing actually is.

A unit test is a small piece of code that checks whether another piece of your code behaves as expected. Think of it like this:

“If I give this function a certain input, does it return the correct output?”

For example, if you have a function that combines a user’s first and last name, a unit test would verify that given the arguments "John" and "Smith", the value "John Smith" would be returned.

Each test focuses on a single unit of functionality — usually one method or function — and confirms it works correctly.

Why Unit Testing Matters

Unit tests help you:

• Catch bugs early
• Avoid breaking existing functionality when making changes
• Document how your code is supposed to behave
• Build confidence as your application grows

Instead of manually checking your app every time you make a change, you can run your tests and instantly know if something broke.

Step 1: Install and Setup Pest

With our introduction to unit testing aside, let’s dig into Pest.

To install Pest, go to: https://pestphp.com/docs/installation

The first set of commands they give us in the instructions will install Pest in our Laravel project:

composer remove phpunit/phpunit
composer require pestphp/pest --dev --with-all-dependencies

During installation, you may see a prompt asking whether to remove PHPUnit. Since Pest uses PHPUnit under the hood, it’s safe to proceed.

Next, we’re told to initialize Pest using the following Artisan command:

php artisan pest:install

This command will create a Pest configuration file at tests/Pest.php. Open this file and chain on the command ->in('Unit') so that in addition to looking for tests in tests/Feature, the test runner will also locate nd run tests in testts/Unit:

pest()->extend(TestCase::class)
 // ->use(Illuminate\Foundation\Testing\RefreshDatabase::class)
    ->in('Feature')
    ->in('Unit'); #  ⭐ Add this line

Step 2: Create a Method to Test

For this example, we have a Customer Model with a simple method called getFullName that concatenates the customer’s first and last name. This is the test we will write our Unit test for.

<?php

# App\Models\Customer.php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Customer extends Model
{
    protected $fillable = [
        'first_name',
        'last_name',
        'email'
    ];

    public function getFullName(): string {
        return $this->first_name . ' ' . $this->last_name;
    }
}

Step 3: Generate a Unit Test

To generate test for our Customer model, run the following command:

php artisan make:test CustomerTest --unit

This command creates a test file at tests/Unit/CustomerTest.php and sets it up specifically for unit testing.

Step 4: Write the Test

Open tests/Unit/CustomerTest.php and replace the default example with a test for our customer model.

<?php

use App\Models\Customer;

test('customer getFullName returns properly formatted full name', function () {

    # Setup
    $customer = new Customer([
        'first_name' => 'John',
        'last_name' => 'Smith'
    ]);

    $fullName = $customer->getFullName();

    # Assertion (every test must include at least one assertion)
    expect($fullName)->toEqual('Smith, John');
});

Observe that Pest uses expect() instead of traditional assertions; see https://pestphp.com/docs/expectations for a list of available expectation methods.

Step 5: Run Your Tests

To run all tests:

php artisan test

You should see your test, in addition to some default/existing tests, all pass successfully. Example:

/Users/Susan/Herd/demo  $ php artisan test

   PASS  Tests\Unit\CustomerTest
  ✓ customer getFullName returns properly formatted full name                                              0.06s  

   PASS  Tests\Unit\ExampleTest
  ✓ that true is true                                                                                      0.01s  

   PASS  Tests\Feature\ExampleTest
  ✓ the application returns a successful response                                                          0.03s  

  Tests:    3 passed (3 assertions)
  Duration: 0.16s

Tip: Run a Specific Test

If your project has many tests, you can run just one:

php artisan test --filter=CustomerTest

This is useful for faster iteration while developing.

Summary

Pest provides a clean, readable way to write tests in Laravel while still leveraging PHPUnit behind the scenes. By focusing on clear test names and simple assertions, you can quickly build confidence in your application’s behavior.