AssertableValueObject.php

<?php

// AssertableValueObject.php

final class AssertionsFailedException extends \RuntimeException
{
}

interface AssertableInterface
{
    /** 
     * @param callable(self):bool $assertion
     */
    public function assert(callable $assertion, string $reason = 'The assertion returned false'): void;
}

trait AssertableTrait
{
  public function assert(callable $assertion, string $reason = ''): void
    {
        if(! ($assertion)($this)){
            throw new AssertionsFailedException($reason);
        }
    }
}
final class ValueObject implements AssertableInterface
{
  use AssertableTrait;
  private string $name;
  public function __construct(string $name)
  {
      $this->name = $name;
      $this->assert(
          static fn(self $my): bool => $my->name !== '', 
          'name is an empty string.'
      );
  }
}

var_dump([
    new ValueObject('p'),
    new ValueObject('')
]);