How to use PHPUnit

https://phpunit.de/getting-started/phpunit-11.html

Requirements:

• PHP
  https://windows.php.net/download#php-8.3
  
  Download and unzip PHP.
• Composer
  https://getcomposer.org/doc/00-intro.md#installation-windows
  
  Install composer, this will add it to your windows PATH to use it in the terminal.
  
  Make sure that this is the path to your unzipped php.exe!

Setup project

• Run composer require --dev phpunit/phpunit
• Run composer require php
• Add a tests directory for your XYZ...Test.php unit tests.
• Add a src directory for your php application code.
• Add autoload to your composer.json so that PHPUnit will be able to access the source files in your src directory like this:

  "autoload": {
    "psr-4": {
      "App\\": "src/"
    }
  },

• Add a phpunit.xml so that PHPUnit will look for tests in the tests folder like this:

<?xml version="1.0" encoding="UTF-8"?>
<phpunit
    stopOnFailure="false">
    <testsuites>
        <testsuite name="Tests">
            <directory>./tests</directory>
        </testsuite>
    </testsuites>
</phpunit>

• Add a tests script to your composer.json to run your tests in the tests directory like this:

  "scripts": {
    "tests": "phpunit --color=always"
  }

• Your composer.json should look like this now:

{
  "autoload": {
    "psr-4": {
      "App\\": "src/"
    }
  },
  "require": {
    "php": "*"
  },
  "require-dev": {
    "phpunit/phpunit": "^11.0"
  },
  "scripts": {
    "tests": "phpunit --color=always"
  }
}

• You're now ready to write your php application, as well as your unit tests!

Example

• You add the counterInterface.php file into your src directory with the following code:

<?php

namespace App;

interface Counter
{
    public function increment(): void;
    public function getCount(): int;
}

• Now, you write a test for the Counter class you will implement after the test!
  Add the counterTest.php file to your tests directory, with the following code:

<?php

declare(strict_types=1);

use PHPUnit\Framework\TestCase;
use App\Counter;

class CounterTest extends TestCase
{
    public function testCounter(): void
    {
        $demo = new Counter();
        for ($i = 0; $i < 10; $i++) {
            $demo->increment();
        }

        $count = $demo->getCount();
        $this->assertEquals(
            10,
            $count,
            "After 10 increments,
            the counter should return a count of 10!
            But the count was $count!"
        );
    }
}

• run your test: composer tests
  And you get the following error:

There was 1 error:

1) CounterTest::testCounter
Error: Class "App\Counter" not found

This is to be expected as we have not implemented the Counter class in our src directory yet!

• Add the new file counter.php in the src directory, with the following code:

<?php

namespace App;

class Counter
{
    private $count = 0;
    public function increment(): void
    {
        $this->count++;
    }
    public function getCount(): int
    {
        return $this->count;
    }
}

• As we have now implemented the Counter class, it is time to check if it passes our testCounter test in the counterTest.php file.
  For that we run composer tests:

There was 1 error:

1) CounterTest::testCounter
Error: Class "App\Counter" not found

If you run in this error run composer update and run composer tests again, as composer is not aware of the Counter class yet!

As we implemented the Counter class correctly, we get the following result:

.                                                                   1 / 1 (100%)

Time: 00:00.006, Memory: 6.00 MB

OK (1 test, 1 assertion)

🎊 Congrats you just did test driven development 🎊
From here on, your good to go.

• But when we introduce a bug on purpose, we can see that our unit test will let us know immediately:
  Let's change private $count = 0; to private $count = 1; in counter.php and run composer tests again:

F                                                                   1 / 1 (100%)

Time: 00:00.013, Memory: 8.00 MB

There was 1 failure:

1) CounterTest::testCounter
After 10 increments,
            the counter should return a count of 10!
            But the count was 11!
Failed asserting that 11 matches expected 10.

C:\Users\roman\Desktop\Nachhilfe\PHPUnit\tests\counterTest.php:18

FAILURES!
Tests: 1, Assertions: 1, Failures: 1.
Script phpunit --color=always handling the tests event returned with error code 1

Now we get this result!

Let's fix the counter class again and change private $count = 1; to private $count = 0; again:

OK (1 test, 1 assertion)

You see thanks to unit tests you will immediately see if you fuck something up!
And that is great.
Now it is your turn to implement your php projects from now on using unit tests and test driven development or TDD in short 🚀.

Coverage

Install xdebug

Run php -i and copy the output to your clipboard!
You can do this directly by running php -i | clip.
Go to https://xdebug.org/wizard and paste your php info:

Then click on the analyze button:

Download the dll and put it in your ext directory in your php installation folder!
Also rename it to php_xdebug.dll.
Then open the php.ini and add these 3 lines at the bottom:

[xdebug]
zend_extension = xdebug
xdebug.mode = coverage

This finalizes your xdebug installation and also sets the usage of xdebug for code coverage analysis.

Create a coverage report

Go to your composer.json and add a coverage script:

"coverage": "phpunit --color=always --coverage-filter src --coverage-html=coverage"

Now your ready to run composer coverage to create a coverage report like this: