testing php applications

Test Organisation And Naming

A test suite is production code for developers. Clear file structure and names make failures faster to diagnose and make missing scenarios easier to notice during review.

Name The Behaviour

A useful test name describes the situation and expected outcome: testCheckoutRejectsExpiredDiscountCode() communicates more than testDiscountCode(). Keep one main reason to fail in each test.

Organise By The Codebase

Mirror the repository where that helps navigation: unit tests for domain rules, integration tests for repositories or adapters, and feature or HTTP tests for application workflows. Keep shared test helpers small; a deep inheritance tree can hide important setup.

PHP example

<?php

declare(strict_types=1);

use PHPUnit\Framework\TestCase;

final class CheckoutTest extends TestCase
{
    public function testCheckoutRejectsExpiredDiscountCode(): void
    {
        // Arrange the expired code, submit checkout, and assert the rejection.
    }
}

The method name makes the failed behaviour visible in CI output. The body should arrange only the state needed for that scenario.

Common Mistakes

Names such as testItWorks() that reveal nothing when CI fails.
One giant test that checks several unrelated rules.
Copy-pasted setup that obscures the meaningful state.
Helpers so abstract that readers cannot see the scenario.

What To Practise

Name tests after behaviour.
Group tests at useful boundaries.
Keep setup readable and local when possible.

Practice

Practice: Rename A Weak Test List

Improve a set of vague test names for a product publishing feature.

Requirements

Cover successful publishing.
Cover a missing title.
Cover an ordinary user attempting an admin action.
Keep each name focused on one outcome.

Show solution

The names should explain CI failures before the file is opened.

PHP example

<?php

declare(strict_types=1);

$testNames = [
    'testAdminCanPublishValidProduct',
    'testPublishingRejectsProductWithoutTitle',
    'testOrdinaryUserCannotPublishProduct',
];

foreach ($testNames as $name) {
    echo $name . PHP_EOL;
}

// Prints:
// testAdminCanPublishValidProduct
// testPublishingRejectsProductWithoutTitle
// testOrdinaryUserCannotPublishProduct

Each test name identifies the actor or input condition and one expected result.