drupalGet() returns 200 on gibberish URL on test

Hi to all,
I provided a patch for the webform module here (version 7.x-4.22, I am working with Drupal 7.69), and am trying to provide a test with it.

My issue is the following : the patch I provided fixes a 500 error I was getting when getting a certain page (namely, /node/mynid/webform-results/table?sort=asc&order=myfieldid). The test I  am trying to provide to go along with it should fail when the patch is not applied (ie. detect the page returns a 500).

In order to prove that, I am creating some a webform node, some submissions to it, and using drupalGet() on the said URL. However, not only does the page not return a 500 erorr, but more importantly when I tried passing a gibberish URL in the testing code (for example, /node/mynid/webform-eqzrvsijekvnzejkvdsvkw) the test passes. Did I miss something setting up my test ? Is this a known issue ? What should I do to circumvent that behavior ?

Thanks for reading me.

My testing code is below :

  public function testWebformSubmissionSort () {
    $path = drupal_get_path('module', 'webform');
    module_load_include('inc', 'webform', 'includes/webform.submissions');
    $this->webformReset();    

    // Create a new Webform test node
    $this->drupalLogin($this->webform_users['admin']);
    $node = $this->webformForm();

    // Submit some sample values
    $this->webformSubmissionExecute('sample');
    $this->webformSubmissionExecute('sample');

    // Get the cid of the interger component.
    foreach ($node->webform['components'] as &$component) {
      if ($component['form_key'] === 'integer') {
        $integer_cid = $component['cid'];
        break;
      }
    }

  // Navigate to the result table, and sort results by the integer field 
  $integer_field_name = $node->webform['components'][$integer_cid]['name']; 
  $this->drupalGet('node/'. $node->nid . '/webform-results/table', array('query' => array('order' => $integer_field_name))); // this line returns 200 even with a gibberish URL, ex /webform-xdvsfjvfsdf


   // Assert the page is loaded correctly 
   $this->assertResponse(200, t('The HTTP response was 200 for the result table sort page.'));
   $this->drupalLogout(); 
  }