diff --git a/core/modules/simpletest/src/BrowserTestBase.php b/core/modules/simpletest/src/BrowserTestBase.php
index f3c01f7..049db12 100644
--- a/core/modules/simpletest/src/BrowserTestBase.php
+++ b/core/modules/simpletest/src/BrowserTestBase.php
@@ -235,6 +235,9 @@
 
   /**
    * Initializes Mink sessions.
+   *
+   * @return \Behat\Mink\Session
+   *   The mink session.
    */
   protected function initMink() {
     $driver = $this->getDefaultDriverInstance();
diff --git a/core/modules/simpletest/tests/src/FunctionalJavascript/BrowserWithJavascriptTest.php b/core/modules/simpletest/tests/src/FunctionalJavascript/BrowserWithJavascriptTest.php
index 676e5b3..c277e79 100644
--- a/core/modules/simpletest/tests/src/FunctionalJavascript/BrowserWithJavascriptTest.php
+++ b/core/modules/simpletest/tests/src/FunctionalJavascript/BrowserWithJavascriptTest.php
@@ -32,7 +32,7 @@ public function testJavascript() {
         return x == 400 && y == 300;
     }());
 JS;
-    $result = $session->wait(1000, $javascript);
+    $result = $this->wait($javascript);
     $this->assertTrue($result);
   }
 
diff --git a/core/modules/toolbar/tests/src/FunctionalJavascript/ToolbarIntegrationTest.php b/core/modules/toolbar/tests/src/FunctionalJavascript/ToolbarIntegrationTest.php
index 6910d71..616cb27 100644
--- a/core/modules/toolbar/tests/src/FunctionalJavascript/ToolbarIntegrationTest.php
+++ b/core/modules/toolbar/tests/src/FunctionalJavascript/ToolbarIntegrationTest.php
@@ -46,11 +46,11 @@ public function testToolbarToggling() {
     $this->assertElementNotPresent('#toolbar-item-administration-tray.toolbar-tray-vertical', 'Toolbar tray is not vertically oriented by default.');
 
     $this->click('#toolbar-item-administration-tray button.toolbar-icon-toggle-vertical');
-    $this->assertTrue($this->wait(1000, 'jQuery("#toolbar-item-administration-tray").hasClass("toolbar-tray-vertical")'));
+    $this->assertTrue($this->wait('jQuery("#toolbar-item-administration-tray").hasClass("toolbar-tray-vertical")'));
     $this->assertElementVisible('#toolbar-item-administration-tray.toolbar-tray-vertical', 'After toggling the orientation the toolbar tray is now displayed vertically.');
 
     $this->click('#toolbar-item-administration-tray button.toolbar-icon-toggle-horizontal');
-    $this->assertTrue($this->wait(1000, 'jQuery("#toolbar-item-administration-tray").hasClass("toolbar-tray-horizontal")'));
+    $this->assertTrue($this->wait('jQuery("#toolbar-item-administration-tray").hasClass("toolbar-tray-horizontal")'));
     $this->assertElementVisible('#toolbar-item-administration-tray.toolbar-tray-horizontal', 'After toggling the orientation a second time the toolbar tray is displayed horizontally again.');
   }
 
diff --git a/core/tests/Drupal/FunctionalJavascriptTests/JavascriptTestBase.php b/core/tests/Drupal/FunctionalJavascriptTests/JavascriptTestBase.php
index 65927a0..906f23e 100644
--- a/core/tests/Drupal/FunctionalJavascriptTests/JavascriptTestBase.php
+++ b/core/tests/Drupal/FunctionalJavascriptTests/JavascriptTestBase.php
@@ -36,7 +36,7 @@ protected function initMink() {
     if (!file_exists($path)) {
       mkdir($path);
     }
-    parent::initMink();
+    return parent::initMink();
   }
 
   /**
@@ -66,15 +66,15 @@ protected function assertElementNotVisible($css_selector, $message = '') {
   /**
    * Waits for the given time or until the given JS condition becomes TRUE.
    *
+   * @param string $condition
+   *   JS condition to wait until it becomes TRUE.
    * @param int $timeout
-   *   Timeout in milliseconds.
-   * @param string|bool $condition
-   *   JS condition, or FALSE to wait for the full duration of the timeout.
+   *   (Optional) Timeout in milliseconds, defaults to 1000.
    *
    * @return bool
    *   The result of the JS condition.
    */
-  protected function wait($timeout, $condition = FALSE) {
+  protected function wait($condition, $timeout = 1000) {
     return $this->getSession()->getDriver()->wait($timeout, $condition);
   }