Testing Abstract Classes using Anonymous Classes

TL;DR

Write the entire anonymous (opens in a new tab) class definition on the spot

$anonymousClass = new class () extends AbstractClass {
    public function __construct() {}
};

What is it?

They can pass arguments through to their constructors, extend other classes, implement interfaces, and use traits just like a normal class can

Example

Abstract base class that contains an unimplemented abstract method.

abstract class AbstractClass
{
    public abstract function abstractMethod();
}

Wrap the abstract method into an anonymous class for execution and testing.

$anonymousClass = new class extends AbstractClass {
    protected function abstractMethod()
    {
        return 'ok';
    }
};
 
$anonymousClass->abstractMethod();