Introduction

The package helps mock internal php functions as simple as possible. Use this package when you need mock such functions as: time(), str_contains(), rand, etc.

Installation

composer require xepozz/internal-mocker --dev

Usage

The main idea is pretty simple: register a Listener for PHPUnit and call the Mocker extension first.

Register a hook

Create new file tests/MockerExtension.php

Paste the following code into the created file:

<?php
declare(strict_types=1);

namespace App\Tests;

use PHPUnit\Runner\BeforeTestHook;
use PHPUnit\Runner\BeforeFirstTestHook;
use Xepozz\InternalMocker\Mocker;
use Xepozz\InternalMocker\MockerState;

final class MockerExtension implements BeforeTestHook, BeforeFirstTestHook
{
    public function executeBeforeFirstTest(): void
    {
        $mocks = [];

        $mocker = new Mocker();
        $mocker->load($mocks);
        MockerState::saveState();
    }

    public function executeBeforeTest(string $test): void
    {
        MockerState::resetState();
    }
}

<extensions>
    <extension class="App\Tests\MockerExtension"/>
</extensions>

Here you have registered extension that will be called every time when you run ./vendor/bin/phpunit.

Register mocks

The package supports a few ways to mock functions:

Runtime mocks
Pre-defined mocks
Mix of two previous ways

Runtime mocks

If you want to make your test case to be used with mocked function you should register it before.

Back to the created MockerExtension::executeBeforeFirstTest and edit the $mocks variable.

$mocks = [
    [
        'namespace' => 'App\Service',
        'name' => 'time',
    ],
];

This mock will proxy every call of time() under the namespace App\Service through a generated wrapper.

When you want to mock result in tests you should write the following code into needed test case:

MockerState::addCondition(
   'App\Service', // namespace
   'time', // function name
   [], // arguments
   100 // result
);

So your test case will look like the following:

<?php
namespace App\Tests;

use App\Service;
use PHPUnit\Framework\TestCase;

class ServiceTest extends TestCase
{
    public function testRun2(): void
    {
        $service = new Service();

        MockerState::addCondition(
            'App\Service',
            'time',
            [],
            100
        );

        $this->assertEquals(100, $service->doSomething());
   }
}

See full example in \Xepozz\InternalMocker\Tests\Integration\DateTimeTest::testRun2

Pre-defined mock

Pre-defined mocks allow you to mock behaviour globally.

It means that you don't need to write MockerState::addCondition(...) into each test case if you want to mock it for whole project.

Keep in mind that the same functions from different namespaces are not the same for Mocker.

So back to the created MockerExtension::executeBeforeFirstTest and edit the $mocks variable.

$mocks = [
    [
        'namespace' => 'App\Service',
        'name' => 'time',
        'result' => 150,
        'arguments' => [],
    ],
];

After this variant each App\Service\time() will return 150.

You can add a lot of mocks. Mocker compares the arguments values with arguments of calling function and returns needed result.

Mix of two previous ways

Mix means that you can use Pre-defined mock at first and Runtime mock after.

State

If you use Runtime mock you may face the problem that after mocking function you still have it mocked in another test cases.

MockerState::saveState() and MockerState::resetState() solves this problem.

These methods save "current" state and unload each Runtime mock mock that was applied.

Using MockerState::saveState() after Mocker->load($mocks) saves only Pre-defined mocks.

Global namespaced functions

Internal functions

Without any additional configuration you can mock only functions that are defined under any not global namespaces: App\, App\Service\, etc. But you cannot mock functions that are defined under global namespace or defined in a use statement, e.g. use time; or \time();.

Workaround

The way you can mock global functions is to disable them in php.ini: https://www.php.net/manual/en/ini.core.php#ini.disable-functions

The best way is to disable them only for tests by running a command with the additional flags:

php -ddisable_functions=${functions} ./vendor/bin/phpunit

Replace ${functions} with the list of functions that you want to mock, separated by commas, e.g.: time,rand.

So now you can mock global functions as well.

Internal function implementation

When you disable a function in php.ini you cannot call it anymore. That means you must implement it by yourself.

Obviously, almost all functions are implemented in PHP looks the same as the Bash ones.

The shortest way to implement a function is to use `bash command` syntax:

$mocks[] = [
   'namespace' => '',
   'name' => 'time',
   'function' => fn () => `date +%s`,
];

Restrictions

Data Providers

Sometimes you may face unpleasant situation when mocked function is not mocking without forced using namespace

function. It may mean that you are trying make PHP interpreter file in @dataProvider. Be careful of it and as a workaround I may suggest you to call the mocker in test's constructor. So first move all code from your extension method executeBeforeFirstTest to new static method and call it in both executeBeforeFirstTest and __construct methods.

final class MyTest extends \PHPUnit\Framework\TestCase
{
    public function __construct(?string $name = null, array $data = [], $dataName = '')
    {
        \App\Tests\MockerExtension::load();
        parent::__construct($name, $data, $dataName);
    }
    
    /// ...
}

final class MockerExtension implements BeforeTestHook, BeforeFirstTestHook
{
    public function executeBeforeFirstTest(): void
    {
        self::load();
    }

    public static function load(): void
    {
        $mocks = [];

        $mocker = new Mocker();
        $mocker->load($mocks);
        MockerState::saveState();
    }

    public function executeBeforeTest(string $test): void
    {
        MockerState::resetState();
    }
}

That all because of PHPUnit 9.5 and lower event management system. Data Provider functionality starts to work before any events, so it's impossible to mock the function at the beginning of the runtime.

roxblnfk / internal-mocker