Getting Started with PHPUnit 9

This tutorial assumes that you use PHP 7.3 or PHP 7.4. You will learn how to write simple unit tests as well as how to download and run PHPUnit.

The documentation for PHPUnit 9 can be found here.

Download

PHP Archive (PHAR)

We distribute a PHP Archive (PHAR) that contains everything you need in order to use PHPUnit 9. Simply download it from here and make it executable:

Composer

You can add PHPUnit as a local, per-project, development-time dependency to your project using Composer:

➜ wget -O phpunit https://phar.phpunit.de/phpunit-9.phar

➜ chmod +x phpunit

➜ ./phpunit --version
PHPUnit 9.0.0 by Sebastian Bergmann and contributors.

➜ composer require --dev phpunit/phpunit ^9

➜ ./vendor/bin/phpunit --version
PHPUnit 9.0.0 by Sebastian Bergmann and contributors.

Please refer to the documentation for details on how to verify PHAR releases of PHPUnit.

The example shown above assumes that composer is on your $PATH.

Your composer.json should look similar to this:

{
    "autoload": {
        "classmap": [
            "src/"
        ]
    },
    "require-dev": {
        "phpunit/phpunit": "^9"
    }
}

Code

src/Email.php

<?php declare(strict_types=1);
final class Email
{
    private $email;

    private function __construct(string $email)
    {
        $this->ensureIsValidEmail($email);

        $this->email = $email;
    }

    public static function fromString(string $email): self
    {
        return new self($email);
    }

    public function __toString(): string
    {
        return $this->email;
    }

    private function ensureIsValidEmail(string $email): void
    {
        if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
            throw new InvalidArgumentException(
                sprintf(
                    '"%s" is not a valid email address',
                    $email
                )
            );
        }
    }
}

Test Code

tests/EmailTest.php

<?php declare(strict_types=1);
use PHPUnit\Framework\TestCase;

final class EmailTest extends TestCase
{
    public function testCanBeCreatedFromValidEmailAddress(): void
    {
        $this->assertInstanceOf(
            Email::class,
            Email::fromString('user@example.com')
        );
    }

    public function testCannotBeCreatedFromInvalidEmailAddress(): void
    {
        $this->expectException(InvalidArgumentException::class);

        Email::fromString('invalid');
    }

    public function testCanBeUsedAsString(): void
    {
        $this->assertEquals(
            'user@example.com',
            Email::fromString('user@example.com')
        );
    }
}

Test Execution

PHP Archive (PHAR)

➜ ./phpunit --bootstrap src/autoload.php tests
PHPUnit 9.0.0 by Sebastian Bergmann and contributors.

...                                                                 3 / 3 (100%)

Time: 70 ms, Memory: 10.00MB

OK (3 tests, 3 assertions)

The above assumes that you have downloaded phpunit.phar and put it into your $PATH as phpunit and that src/autoload.php is a script that sets up autoloading for the classes that are to be tested. Such a script is commonly generated using a tool such as phpab.

Composer

➜ ./vendor/bin/phpunit tests
PHPUnit 9.0.0 by Sebastian Bergmann and contributors.

...                                                                 3 / 3 (100%)

Time: 70 ms, Memory: 10.00MB

OK (3 tests, 3 assertions)

The above assumes that vendor/autoload.php, the autoloader script managed by Composer, exists and is able to load the code for the Email class. Depending on how you set up autoloading, you may need to run composer dump-autoload now.

--bootstrap src/autoload.php instructs the PHPUnit command-line test runner to include src/autoload.php before the tests are run.

tests instructs the PHPUnit command-line test runner to execute all tests found declared in *Test.php sourcecode files in the tests directory.

tests instructs the PHPUnit command-line test runner to execute all tests found declared in *Test.php sourcecode files in the tests directory.

TestDox

Below you see an alternative output which is based on the idea that the name of a test can be used to document the behavior that is verified by the test:

➜ ./phpunit --bootstrap src/autoload.php --testdox tests
PHPUnit 9.0.0 by Sebastian Bergmann and contributors.

Email
 ✔ Can be created from valid email address
 ✔ Cannot be created from invalid email address
 ✔ Can be used as string

➜ ./vendor/bin/phpunit --testdox tests
PHPUnit 9.0.0 by Sebastian Bergmann and contributors.

Email
 ✔ Can be created from valid email address
 ✔ Cannot be created from invalid email address
 ✔ Can be used as string