How to test private methods and set private properties with phpunit

testPrivateMethodsAndPropertiesWithPhpUnit.php

<?php 

// Test private methid

$reflectionClass = new \ReflectionClass(TestClass::class);
$testMethod = $reflectionClass->getMethod('testMethod');
$testMethod->setAccessible(true);

$testingClass = new TestClass();

$result = $testMethod->invokeArgs($testingClass, ['argument 1', 'argument 2']);

// Set private property

$reflectionProperty = $reflectionClass->getProperty('testProperty');
$reflectionProperty->setAccessible(true);
$reflectionProperty->setValue($testingClass, 'Value');