diff --git a/core/modules/outside_in/tests/src/FunctionalJavascript/OutsideInBlockFormTest.php b/core/modules/outside_in/tests/src/FunctionalJavascript/OutsideInBlockFormTest.php
index b48b8b767a..eb86487aa3 100644
--- a/core/modules/outside_in/tests/src/FunctionalJavascript/OutsideInBlockFormTest.php
+++ b/core/modules/outside_in/tests/src/FunctionalJavascript/OutsideInBlockFormTest.php
@@ -526,4 +526,59 @@ public function testValidationMessages() {
     }
   }
 
+  /**
+   * Clicks a contextual link.
+   *
+   * @todo Remove this function when related trait added in
+   *   https://www.drupal.org/node/2821724.
+   *
+   * @param string $selector
+   *   The selector for the element that contains the contextual link.
+   * @param string $link_locator
+   *   The link id, title, or text.
+   * @param bool $force_visible
+   *   If true then the button will be forced to visible so it can be clicked.
+   */
+  protected function clickContextualLink($selector, $link_locator, $force_visible = TRUE) {
+    if ($force_visible) {
+      $this->toggleContextualTriggerVisibility($selector);
+    }
+
+    $element = $this->getSession()->getPage()->find('css', $selector);
+    $element->find('css', '.contextual button')->press();
+    $element->findLink($link_locator)->click();
+
+    if ($force_visible) {
+      $this->toggleContextualTriggerVisibility($selector);
+    }
+  }
+
+  /**
+   * Toggles the visibility of a contextual trigger.
+   *
+   * @todo Remove this function when related trait added in
+   *   https://www.drupal.org/node/2821724.
+   *
+   * @param string $selector
+   *   The selector for the element that contains the contextual link.
+   */
+  protected function toggleContextualTriggerVisibility($selector) {
+    // Hovering over the element itself with should be enough, but does not
+    // work. Manually remove the visually-hidden class.
+    $this->getSession()->executeScript("jQuery('{$selector} .contextual .trigger').toggleClass('visually-hidden');");
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getTestThemes() {
+    $themes = parent::getTestThemes();
+    // Remove 'seven' theme. Setting Tray "Edit Mode" will not work with 'seven'
+    // because it removes all contextual links the off-canvas dialog should.
+    if (($key = array_search('seven', $themes)) !== FALSE) {
+      unset($themes[$key]);
+    }
+    return $themes;
+  }
+
 }
diff --git a/core/modules/system/tests/src/FunctionalJavascript/OffCanvasTest.php b/core/modules/system/tests/src/FunctionalJavascript/OffCanvasTest.php
index a307841317..240362ba21 100644
--- a/core/modules/system/tests/src/FunctionalJavascript/OffCanvasTest.php
+++ b/core/modules/system/tests/src/FunctionalJavascript/OffCanvasTest.php
@@ -107,13 +107,4 @@ public function testNarrowWidth() {
     }
   }
 
-  /**
-   * {@inheritdoc}
-   */
-  protected function getTestThemes() {
-    // Add 'seven' theme. Setting Tray "Edit Mode" will not work with 'seven'
-    // because it removes all contextual links the off-canvas dialog should.
-    return array_merge(parent::getTestThemes(), ['seven']);
-  }
-
 }
diff --git a/core/modules/system/tests/src/FunctionalJavascript/OffCanvasTestBase.php b/core/modules/system/tests/src/FunctionalJavascript/OffCanvasTestBase.php
index 6aa810568d..6ee6190d7b 100644
--- a/core/modules/system/tests/src/FunctionalJavascript/OffCanvasTestBase.php
+++ b/core/modules/system/tests/src/FunctionalJavascript/OffCanvasTestBase.php
@@ -73,6 +73,8 @@ protected function getTray() {
    *   CSS selector.
    * @param int $timeout
    *   (optional) Timeout in milliseconds, defaults to 10000.
+   *
+   * @todo Remove in https://www.drupal.org/node/2892440.
    */
   protected function waitForNoElement($selector, $timeout = 10000) {
     $condition = "(jQuery('$selector').length == 0)";
@@ -80,55 +82,13 @@ protected function waitForNoElement($selector, $timeout = 10000) {
   }
 
   /**
-   * Clicks a contextual link.
-   *
-   * @todo Remove this function when related trait added in
-   *   https://www.drupal.org/node/2821724.
-   *
-   * @param string $selector
-   *   The selector for the element that contains the contextual link.
-   * @param string $link_locator
-   *   The link id, title, or text.
-   * @param bool $force_visible
-   *   If true then the button will be forced to visible so it can be clicked.
-   */
-  protected function clickContextualLink($selector, $link_locator, $force_visible = TRUE) {
-    if ($force_visible) {
-      $this->toggleContextualTriggerVisibility($selector);
-    }
-
-    $element = $this->getSession()->getPage()->find('css', $selector);
-    $element->find('css', '.contextual button')->press();
-    $element->findLink($link_locator)->click();
-
-    if ($force_visible) {
-      $this->toggleContextualTriggerVisibility($selector);
-    }
-  }
-
-  /**
-   * Toggles the visibility of a contextual trigger.
-   *
-   * @todo Remove this function when related trait added in
-   *   https://www.drupal.org/node/2821724.
-   *
-   * @param string $selector
-   *   The selector for the element that contains the contextual link.
-   */
-  protected function toggleContextualTriggerVisibility($selector) {
-    // Hovering over the element itself with should be enough, but does not
-    // work. Manually remove the visually-hidden class.
-    $this->getSession()->executeScript("jQuery('{$selector} .contextual .trigger').toggleClass('visually-hidden');");
-  }
-
-  /**
    * Get themes to test.
    *
    * @return string[]
    *   Theme names to test.
    */
   protected function getTestThemes() {
-    return ['bartik', 'stark', 'classy', 'stable'];
+    return ['bartik', 'stark', 'classy', 'stable', 'seven'];
   }
 
   /**