mark_as_published_test.php

<?php
// Article.php
final class Article
{
  // properties, getters
  public function markAsPublished(): self
  {
    if ($this->status === Article::DELETED)) {
        throw new LogicException(sprintf("Cannot mark as published as the article is deleted"));
      }
  }
  
  $this->status = Article::PUBLISHED;
  
  return $this;
 }
}

// ArticleTest.php
use PHPUnit\Framework\TestCase;

final class ArticleTest extends TestCase
{
    public function testItMarksAsPublished(): void
    {
      $article = (new Article)->markAsPublished();
      // ✨ If the constant value change this test will fail 
      self::assertEquals('published', $article->getStatus());
    }
}