$this->drupalLogin($admin_user);
// Add a content block with custom CSS class.
$this->drupalGet('admin/structure/block/add/system_main_block/classy', ['query' => ['region' => 'content']]);
$this->drupalLogin($admin_user);
// Add a content block with custom CSS class.
$this->drupalGet('admin/structure/block/add/system_main_block/classy', ['query' => ['region' => 'content']]);