diff --git a/core/modules/views/lib/Drupal/views/Tests/Plugin/StyleGridTest.php b/core/modules/views/lib/Drupal/views/Tests/Plugin/StyleGridTest.php
index 284d35e..da2b95c 100644
--- a/core/modules/views/lib/Drupal/views/Tests/Plugin/StyleGridTest.php
+++ b/core/modules/views/lib/Drupal/views/Tests/Plugin/StyleGridTest.php
@@ -15,7 +15,7 @@
  *
  * @see \Drupal\views\Plugin\views\style\Grid
  */
-class StyleGridTest extends PluginUnitTestBase {
+class StyleGridTest extends PluginTestBase {

   /**
    * Views used by this test.
@@ -29,6 +29,9 @@ class StyleGridTest extends PluginUnitTestBase {
    */
   protected $alignmentsTested = array();

+  /**
+   * {@inheritdoc}
+   */
   public static function getInfo() {
     return array(
       'name' => 'Style: Grid',
@@ -38,6 +41,14 @@ public static function getInfo() {
   }

   /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+    $this->enableViewsTestModule();
+  }
+
+  /**
    * Tests the grid style.
    */
   public function testGrid() {
@@ -71,8 +82,10 @@ protected function assertGrid(ViewExecutable $view, $alignment, $columns) {
     $this->executeView($view);
     $output = $view->preview();
     $output = drupal_render($output);
+    $this->drupalSetContent($output, 'internal://test-grid');
     if (!in_array($alignment, $this->alignmentsTested)) {
-      $this->assertTrue(strpos($output, "<div class=\"views-view-grid $alignment cols-$columns clearfix\">") !== FALSE, ucfirst($alignment) . " grid markup displays correctly.");
+      $result = $this->xpath('//div[contains(@class, "views-view-grid") and contains(@class, :alignment) and contains(@class, :columns)]', array(':alignment' => $alignment, ':columns' => 'cols-' . $columns));
+      $this->assertTrue(count($result), ucfirst($alignment) . " grid markup detected.");
       $this->alignmentsTested[] = $alignment;
     }
     $width = '0';
@@ -83,14 +96,12 @@ protected function assertGrid(ViewExecutable $view, $alignment, $columns) {
       case 2: $width = '50'; break;
       case 1: $width = '100'; break;
     }
-    $clearfix = '';
-    if ($alignment == 'vertical') {
-      $clearfix = ' clearfix';
-    }
-    $this->assertTrue(strpos($output, "views-col col-$columns$clearfix\" style=\"width: $width") !== FALSE, ucfirst($alignment) . " $columns column grid: automatic width calculated correctly.");
-    // Test to make sure column count does not exceed style option.
-    $extraColumn = $columns + 1;
-    $this->assertFalse(strpos($output, "col-$extraColumn") !== FALSE, ucfirst($alignment) . " $columns column grid: no extraneous columns exist.");
+    // Ensure last column exists.
+    $result = $this->xpath('//div[contains(@class, "views-col") and contains(@class, :columns) and starts-with(@style, :width)]', array(':columns' => 'col-' . $columns, ':width' => 'width: ' . $width));
+    $this->assertTrue(count($result), ucfirst($alignment) . " $columns column grid: last column exists and automatic width calculated correctly.");
+    // Ensure no extra columns were generated.
+    $result = $this->xpath('//div[contains(@class, "views-col") and contains(@class, :columns)]', array(':columns' => 'col-' . ($columns + 1)));
+    $this->assertFalse(count($result), ucfirst($alignment) . " $columns column grid: no extraneous columns exist.");
   }

 }