Unit Testing with PHPUnit

Laravel ships with PHPUnit configured out of the box, making it straightforward to write focused, isolated tests for individual pieces of application logic.

Generating a Test

php artisan make:test PriceCalculatorTest --unit

The --unit flag places the test under tests/Unit, where classes are tested in isolation without booting the full Laravel application.

A Simple Example

public function test_discount_is_applied_correctly()
{
    $calculator = new PriceCalculator();
    $result = $calculator->applyDiscount(100, 10);

    $this->assertEquals(90, $result);
}

Running Tests

php artisan test
./vendor/bin/phpunit

Why Unit Tests Matter

• Catch regressions early, before code reaches production
• Document expected behaviour of individual classes and methods
• Run fast since they avoid hitting the database or HTTP layer

Unit tests are ideal for isolated logic, but most Laravel applications also need to verify that full HTTP requests behave correctly — which is where feature tests come in.