diff -u b/core/modules/views/src/Plugin/views/style/StylePluginBase.php b/core/modules/views/src/Plugin/views/style/StylePluginBase.php
--- b/core/modules/views/src/Plugin/views/style/StylePluginBase.php
+++ b/core/modules/views/src/Plugin/views/style/StylePluginBase.php
@@ -215,7 +215,7 @@
       if ($this->usesFields() && $this->view->field) {
         // Split the class on spaces and twig tokens.
         $classes = preg_split('/(\s|{{[^}]*}})/', $class, -1, PREG_SPLIT_DELIM_CAPTURE);
-        foreach($classes as &$token_class) {
+        foreach ($classes as &$token_class) {
           $token_class = strip_tags($this->tokenizeValue($token_class, $row_index));
           // Convert any non-space elements to a nice clean class name.
           if (!empty($token_class) && $token_class != ' ') {
diff -u b/core/modules/views/tests/src/Unit/Plugin/views/style/StylePluginBaseTest.php b/core/modules/views/tests/src/Unit/Plugin/views/style/StylePluginBaseTest.php
--- b/core/modules/views/tests/src/Unit/Plugin/views/style/StylePluginBaseTest.php
+++ b/core/modules/views/tests/src/Unit/Plugin/views/style/StylePluginBaseTest.php
@@ -16,13 +16,6 @@
   use HandlerTestTrait;
 
   /**
-   * The mocked path renderer.
-   *
-   * @var \Drupal\Core\Render\RendererInterface|\PHPUnit_Framework_MockObject_MockObject
-   */
-  protected $renderer;
-
-  /**
    * @covers ::getRowClass
    * @dataProvider providerTestGetRowClass
    */
@@ -32,7 +25,7 @@
 
     $row_plugin = $this->prophesize(RowPluginBase::class);
     $row_plugin->usesFields()->willReturn(TRUE);
-    
+
     $field = $this->prophesize(FieldPluginBase::class);
     $this->executable->field['test'] = $field->reveal();
 
@@ -48,6 +41,11 @@
     $this->assertEquals($expected_classes, $style_plugin->getRowClass(0));
   }
 
+  /**
+   * Data provider for testGetRowClass().
+   *
+   * @return array
+   */
   public function providerTestGetRowClass() {
     $data = [];