Using PHPUnit: A Comprehensive Guide with Code Examples (+ Symfony integration)

Introduction

PHPUnit is a widely-used PHP unit testing framework in software development. It provides a comprehensive set of tools and features to write and execute automated tests for your PHP applications. In this article, we will explore the usage of PHPUnit and provide code examples to help you get started.

Section 1: Installing PHPUnit

The first step to using PHPUnit is installing it in your development environment. Here’s how to do it:

1.1. Using Composer

PHPUnit can be installed via Composer, the PHP dependency manager. Make sure you have Composer installed on your machine, then run the following command in your terminal:

composer require --dev phpunit/phpunit

This command will download and install PHPUnit in your project as a development dependency.

1.2. Global Installation

You can also install PHPUnit globally on your system using the following Composer command:

composer global require phpunit/phpunit

This will make PHPUnit available as an executable command in any project.

Section 2: Writing Tests with PHPUnit

PHPUnit offers a simple and expressive syntax for writing unit tests. In this section, we will look at the different features of PHPUnit for writing effective tests.

2.1. Test Structure

In PHPUnit, each unit test is a method within a test class. These test classes are typically named following the convention ClassNameTest. You can use the @test annotation or the test prefix to indicate the test methods.

use PHPUnit\Framework\TestCase;

class MathTest extends TestCase
{
    public function testAddition()
    {
        // Test code
    }

    public function testSubtraction()
    {
        // Test code
    }
}

2.2. Assertions

PHPUnit provides a set of assertions to check the expected results of tests. For example, you can use assertEquals to verify if two values are equal, assertTrue to check if a condition is true, and so on.

public function testAddition()
{
    $result = Math::add(2, 3);
    $this->assertEquals(5, $result);
}

2.3. Test Lifecycle Methods

PHPUnit provides test lifecycle methods that allow you to set up and clean up resources before and after each test. For example, setUp is executed before each test, and tearDown is executed after each test.

use PHPUnit\Framework\TestCase;

class DatabaseTest extends TestCase
{
    public function setUp(): void
    {
        // Database initialization code
    }

    public function tearDown(): void
    {
        // Database cleanup code
    }

    public function testInsertData()
    {
        // Data insertion test code
    }

    public function testDeleteData()
    {
        // Data deletion test code
    }
}

Section 4: Using PHPUnit with Symfony

If you’re developing a Symfony application, you can easily integrate PHPUnit to write and execute unit tests. Here’s how:

4.1. Install PHPUnit with Symfony Flex

If you’re using Symfony Flex, you can install PHPUnit as a development dependency by running the following command in your terminal:

composer require --dev symfony/phpunit-bridge

This will install PHPUnit and the PHPUnit Bridge, which makes integrating PHPUnit with Symfony easier.

4.2. Writing Tests with Symfony

In Symfony, unit tests are typically placed in the tests/ directory at the root of your project. You can create a test class for each class you want to test.

Here’s an example of a test class for a Symfony controller:

use Symfony\Bundle\FrameworkBundle\Test\WebTestCase;

class ProductControllerTest extends WebTestCase
{
    public function testShowAction()
    {
        $client = static::createClient();
        $client->request('GET', '/product/1');

        $this->assertEquals(200, $client->getResponse()->getStatusCode());
    }
}

4.3. Running Tests with Symfony Console

To execute your PHPUnit tests in a Symfony project, you can use the Symfony console. Use the following command in your terminal:

php bin/console phpunit

This will run all the unit tests present in the tests/ directory of your project.

Conclusion

PHPUnit is a powerful tool for writing unit tests in PHP, and its integration with Symfony makes testing in Symfony projects more convenient. By following the steps outlined in this article, you’ll be able to use PHPUnit to test your PHP applications, including Symfony applications, and ensure their proper functioning.