diff --git a/core/tests/Drupal/Tests/Component/Datetime/DateTimePlusTest.php b/core/tests/Drupal/Tests/Component/Datetime/DateTimePlusTest.php
index ba62ae0..7ae0c79 100644
--- a/core/tests/Drupal/Tests/Component/Datetime/DateTimePlusTest.php
+++ b/core/tests/Drupal/Tests/Component/Datetime/DateTimePlusTest.php
@@ -202,7 +202,7 @@ public function testDateFormat($input, $timezone, $format, $format_date, $expect
    * @expectedException \Exception
    */
   public function testInvalidDates($input, $timezone, $format, $message) {
-    $date = DateTimePlus::createFromFormat($format, $input, $timezone);
+    DateTimePlus::createFromFormat($format, $input, $timezone);
   }
 
   /**
diff --git a/core/tests/Drupal/Tests/Core/Asset/CssCollectionRendererUnitTest.php b/core/tests/Drupal/Tests/Core/Asset/CssCollectionRendererUnitTest.php
index fecb135..29262bc 100644
--- a/core/tests/Drupal/Tests/Core/Asset/CssCollectionRendererUnitTest.php
+++ b/core/tests/Drupal/Tests/Core/Asset/CssCollectionRendererUnitTest.php
@@ -154,18 +154,7 @@ function setUp() {
    * @see testRender
    */
   function providerTestRender() {
-    // Default for 'browsers' key in CSS asset.
-    $browsers_default = array('IE' => TRUE, '!IE' => TRUE);
-
-    // Defaults for LINK and STYLE elements.
-    $link_element_defaults = array(
-
-    );
-    $style_element_defaults = array(
-      '#type' => 'html_tag',
-      '#tag' => 'style',
-    );
-
+    
     $create_link_element = function($href, $media = 'all', $browsers = array()) {
       return array(
         '#type' => 'html_tag',
diff --git a/core/tests/Drupal/Tests/Core/Plugin/Discovery/DerivativeDiscoveryDecoratorTest.php b/core/tests/Drupal/Tests/Core/Plugin/Discovery/DerivativeDiscoveryDecoratorTest.php
index a46f42c..d3ab927 100644
--- a/core/tests/Drupal/Tests/Core/Plugin/Discovery/DerivativeDiscoveryDecoratorTest.php
+++ b/core/tests/Drupal/Tests/Core/Plugin/Discovery/DerivativeDiscoveryDecoratorTest.php
@@ -72,7 +72,7 @@ public function testGetDerivativeFetcherWithAnnotationObjects() {
       ->will($this->returnValue($definitions));
 
     $discovery = new DerivativeDiscoveryDecorator($discovery_main);
-    $definitions = $discovery->getDefinitions();
+    $discovery->getDefinitions();
 
     // Ensure that both test derivatives got added.
     $this->assertEquals(2, count($definitions));
diff --git a/core/tests/Drupal/Tests/Core/Routing/MimeTypeMatcherTest.php b/core/tests/Drupal/Tests/Core/Routing/MimeTypeMatcherTest.php
index b407fe8..49593a8 100644
--- a/core/tests/Drupal/Tests/Core/Routing/MimeTypeMatcherTest.php
+++ b/core/tests/Drupal/Tests/Core/Routing/MimeTypeMatcherTest.php
@@ -106,7 +106,7 @@ public function testNoRouteFound() {
     // This should throw NotAcceptableHttpException.
     $request = Request::create('path/two', 'GET');
     $request->headers->set('Accept', 'application/json, text/xml;q=0.9');
-    $routes = $matcher->filter($routes, $request);
+    $matcher->filter($routes, $request);
   }
 
 }