I am trying to setup a simple test that tests some breadcrumb altering code I have introduced only for a specific content type.

Here is the test, still just barebones:


    namespace Drupal\mymodule_breadcrumbs\Tests;
    
    use Drupal\simpletest\WebTestBase;
    
    /**
     * Class ArticleBreadcrumbTest
     * @group mymodule_breadcrumbs
     */
    class ArticleBreadcrumbTest extends WebTestBase {
      protected $node;
      private $account;
    
      /**
       * Modules to install.
       * @var array
       */
      public static $modules = ['node', 'mymodule_breadcrumbs', 'menu_breadcrumb'];
    
      /**
       * Set up our test.
       */
      public function setUp() {
        parent::setUp();
    
        // create admin user
        $this->account = $this->drupalCreateUser(['administer site configuration', 'administer content']);
    
        // create article node
        $this->node = $this->drupalCreateNode(array(
          'title' => t('Test Article'),
          'type' => 'article',
          'status' => 1,
        ));
      }
    
      public function testNodeTitleIsInBreadcrumb() {
        $this->drupalGet('node/' . $this->node->id());
        $this->assertResponse(200);
        #$this->assertText('Home > ' . $this->node->getTitle(), 'Breadcrumb contains the node title.');
        // get page
        // test that breadcrumb is correct per node title
        // change node title
        // save node
        // visit node, check that breadcrumb is updated
      }
    }

However, I am getting this error and not sure what to make of it:

    The website encountered an unexpected error. Please try again later.
    
    InvalidArgumentException: Invalid database prefix: in Drupal\Core\Test\TestDatabase->__construct() (line 81 of core/lib/Drupal/Core/Test/TestDatabase.php).
    simpletest_log_read(NULL, , ) (Line: 476)
    _simpletest_batch_finished(, Array, Array, '1 sec')
    call_user_func_array('_simpletest_batch_finished', Array) (Line: 414)
    _batch_finished() (Line: 81)
    _batch_page(Object) (Line: 55)
    Drupal\system\Controller\BatchController->batchPage(Object)
    call_user_func_array(Array, Array) (Line: 123)
    Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 574)
    Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 124)
    Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) (Line: 97)
    Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}()
    call_user_func_array(Object, Array) (Line: 144)
    Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 64)
    Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 57)
    Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 47)
    Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 99)
    Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 78)
    Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 47)
    Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 50)
    Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
    Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 652)
    Drupal\Core\DrupalKernel->handle(Object) (Line: 19)

It's a very basic test, why would it cause an error like that?