diff --git a/core/lib/Drupal/Core/Datetime/Date.php b/core/lib/Drupal/Core/Datetime/Date.php
index 72845d5..0510fa4 100644
--- a/core/lib/Drupal/Core/Datetime/Date.php
+++ b/core/lib/Drupal/Core/Datetime/Date.php
@@ -156,15 +156,16 @@ public function format($timestamp, $type = 'medium', $format = '', $timezone = N
    * @param int $interval
    *   The length of the interval in seconds.
    * @param int $granularity
-   *   How many different units to display in the string.
+   *   (optional) How many different units to display in the string (2 by
+   *   default).
    * @param string $langcode
-   *   (Optional) language code to translate to a language other than
-   *   what is used to display the page.
+   *   (optional) Language code to translate to a language other than what is
+   *   used to display the page. Defaults to NULL.
    *
    * @return string
    *   A translated string representation of the interval.
    */
-  public function formatInterval($interval, $granularity, $langcode) {
+  public function formatInterval($interval, $granularity = 2, $langcode = NULL) {
     $output = '';
     foreach ($this->units as $key => $value) {
       $key = explode('|', $key);
diff --git a/core/tests/Drupal/Tests/Core/Datetime/DateTest.php b/core/tests/Drupal/Tests/Core/Datetime/DateTest.php
index 9be0fc9..32d2103 100644
--- a/core/tests/Drupal/Tests/Core/Datetime/DateTest.php
+++ b/core/tests/Drupal/Tests/Core/Datetime/DateTest.php
@@ -59,16 +59,12 @@ public static function getInfo() {
   }
 
   protected function setUp() {
-    $this->entityManager = $this->getMockBuilder('Drupal\Core\Entity\EntityManager')
-      ->disableOriginalConstructor()
-      ->getMock();
+    $this->entityManager = $this->getMock('Drupal\Core\Entity\EntityManagerInterface');
     $this->languageManager = $this->getMockBuilder('Drupal\Core\Language\LanguageManager')
       ->disableOriginalConstructor()
       ->getMock();
     $this->stringTranslation = $this->getMock('Drupal\Core\StringTranslation\TranslationInterface');
 
-
-
     $this->date = new Date($this->entityManager, $this->languageManager, $this->stringTranslation);
   }
 
@@ -79,7 +75,7 @@ protected function setUp() {
    *
    * @see \Drupal\Core\Datetime\Date::formatInterval()
    */
-  public function testFormatInterval($interval, $granularity, $expected, $langcode = 'en') {
+  public function testFormatInterval($interval, $granularity, $expected, $langcode = NULL) {
     // Mocks a simple formatPlural implementation.
     $this->stringTranslation->expects($this->any())
       ->method('formatPlural')
@@ -88,7 +84,13 @@ public function testFormatInterval($interval, $granularity, $expected, $langcode
         return $count == 1 ? $one : str_replace('@count', $count, $multiple);
       }));
 
-    $result = $this->date->formatInterval($interval, $granularity, $langcode);
+    // Check if the granularity is specified.
+    if ($granularity) {
+      $result = $this->date->formatInterval($interval, $granularity, $langcode);
+    }
+    else {
+      $result = $this->date->formatInterval($interval);
+    }
 
     $this->assertEquals($expected, $result);
   }
@@ -121,6 +123,8 @@ public function providerTestFormatInterval() {
       array(2592000 * 2 + 604800 * 3 + 86400 * 4, 3, '2 months 3 weeks 4 days'),
       // Check for the langcode.
       array(61, 1, '1 min', 'xxx-lolspeak'),
+      // Check with an unspecified granularity.
+      array(61, NULL, '1 min 1 sec'),
     );
 
     return $data;