Update to Drupal 8.1.9. For more information, see https://www.drupal.org/project/drupal/releases/8.1.9

core/tests/Drupal/Tests/BrowserTestBase.php

@@ -1575,7 +1575,7 @@ abstract class BrowserTestBase extends \PHPUnit_Framework_TestCase {
    * Retrieves the plain-text content from the current page.
    */
   protected function getTextContent() {
-    return $this->getSession()->getPage()->getContent();
+    return $this->getSession()->getPage()->getText();
   }
 
   /**

core/tests/Drupal/Tests/Core/Datetime/DateTest.php

@@ -2,6 +2,7 @@
 
 namespace Drupal\Tests\Core\Datetime;
 
+use Drupal\Core\Cache\CacheableMetadata;
 use Drupal\Core\Datetime\DateFormatter;
 use Drupal\Core\Datetime\FormattedDateDiff;
 use Drupal\Core\DependencyInjection\ContainerBuilder;
@@ -392,6 +393,38 @@ class DateTest extends UnitTestCase {
     return $data;
   }
 
+  /**
+   * Tests FormattedDateDiff.
+   *
+   * @covers \Drupal\Core\Datetime\FormattedDateDiff::toRenderable
+   * @covers \Drupal\Core\Datetime\FormattedDateDiff::getString
+   * @covers \Drupal\Core\Datetime\FormattedDateDiff::getCacheMaxAge
+   */
+  public function testFormattedDateDiff() {
+    $string = '10 minutes';
+    $max_age = 60;
+    $object = new FormattedDateDiff($string, $max_age);
+
+    // Test conversion to a render array.
+    $expected = [
+      '#markup' => $string,
+      '#cache' => [
+        'max-age' => $max_age,
+      ],
+    ];
+    $this->assertArrayEquals($expected, $object->toRenderable());
+
+    // Test retrieving the formatted time difference string.
+    $this->assertEquals($string, $object->getString());
+
+    // Test applying cacheability data to an existing build.
+    $build = [];
+    CacheableMetadata::createFromObject($object)->applyTo($build);
+    $this->assertEquals($max_age, $build['#cache']['max-age']);
+    // Test the BC layer.
+    $this->assertSame($object->getCacheMaxAge(), $object->getMaxAge());
+  }
+
   /**
    * Creates a UNIX timestamp given a date and time string in the format
    * year-month-day hour:minute:seconds (e.g. 2013-12-11 10:09:08).

core/tests/Drupal/Tests/UnitTestCase.php

@@ -198,8 +198,8 @@ abstract class UnitTestCase extends \PHPUnit_Framework_TestCase {
   /**
    * Returns a stub translation manager that just returns the passed string.
    *
-   * @return \PHPUnit_Framework_MockObject_MockBuilder
-   *   A MockBuilder of \Drupal\Core\StringTranslation\TranslationInterface
+   * @return \PHPUnit_Framework_MockObject_MockObject|\Drupal\Core\StringTranslation\TranslationInterface
+   *   A mock translation object.
    */
   public function getStringTranslationStub() {
     $translation = $this->getMock('Drupal\Core\StringTranslation\TranslationInterface');