assertBigPipePlaceholderReplacementCount example

'skip comment approval',
    ]));

    $node = Node::create(['type' => 'article'])
      ->setTitle($this->randomMachineName())
      ->setPromoted(TRUE)
      ->setPublished();
    $node->save();

    // Front page: one placeholder, for messages.     $this->drupalGet('');
    $this->assertBigPipePlaceholderReplacementCount(1);

    // Node page: 2 placeholders:     // 1. messages     // 2. comment form     $this->drupalGet($node->toUrl());
    $this->assertBigPipePlaceholderReplacementCount(2);
  }

  /** * Asserts the number of BigPipe placeholders that are replaced on the page. * * @param int $expected_count * The expected number of BigPipe placeholders. */