diff --git a/core/tests/Drupal/Tests/Component/Diff/Engine/DiffEngineTest.php b/core/tests/Drupal/Tests/Component/Diff/Engine/DiffEngineTest.php
index a1c001b..80f2093 100644
--- a/core/tests/Drupal/Tests/Component/Diff/Engine/DiffEngineTest.php
+++ b/core/tests/Drupal/Tests/Component/Diff/Engine/DiffEngineTest.php
@@ -8,6 +8,10 @@
 namespace Drupal\Tests\Component\Diff\Engine;
 
 use Drupal\Component\Diff\Engine\DiffEngine;
+use Drupal\Component\Diff\Engine\DiffOpAdd;
+use Drupal\Component\Diff\Engine\DiffOpCopy;
+use Drupal\Component\Diff\Engine\DiffOpChange;
+use Drupal\Component\Diff\Engine\DiffOpDelete;
 
 /**
  * Test DiffEngine class.
@@ -28,40 +32,40 @@ class DiffEngineTest extends \PHPUnit_Framework_TestCase {
   public function provideTestDiff() {
     return [
       [[], [], []],
-      [['Drupal\Component\Diff\Engine\DiffOpAdd'], [], ['a']],
-      [['Drupal\Component\Diff\Engine\DiffOpCopy'], ['a'], ['a']],
-      [['Drupal\Component\Diff\Engine\DiffOpChange'], ['a'], ['b']],
+      [[DiffOpAdd::class], [], ['a']],
+      [[DiffOpCopy::class], ['a'], ['a']],
+      [[DiffOpChange::class], ['a'], ['b']],
       [
         [
-          'Drupal\Component\Diff\Engine\DiffOpCopy',
-          'Drupal\Component\Diff\Engine\DiffOpChange',
+          DiffOpCopy::class,
+          DiffOpChange::class,
         ],
         ['a', 'b'],
         ['a', 'c'],
       ],
       [
         [
-          'Drupal\Component\Diff\Engine\DiffOpCopy',
-          'Drupal\Component\Diff\Engine\DiffOpChange',
-          'Drupal\Component\Diff\Engine\DiffOpCopy',
+          DiffOpCopy::class,
+          DiffOpChange::class,
+          DiffOpCopy::class,
         ],
         ['a', 'b', 'd'],
         ['a', 'c', 'd'],
       ],
       [
         [
-          'Drupal\Component\Diff\Engine\DiffOpCopy',
-          'Drupal\Component\Diff\Engine\DiffOpChange',
-          'Drupal\Component\Diff\Engine\DiffOpCopy',
-          'Drupal\Component\Diff\Engine\DiffOpAdd'
+          DiffOpCopy::class,
+          DiffOpChange::class,
+          DiffOpCopy::class,
+          DiffOpAdd::class,
         ],
         ['a', 'b', 'd'],
         ['a', 'c', 'd', 'e'],
       ],
       [
         [
-          'Drupal\Component\Diff\Engine\DiffOpCopy',
-          'Drupal\Component\Diff\Engine\DiffOpDelete',
+          DiffOpCopy::class,
+          DiffOpDelete::class,
         ],
         ['a', 'b', 'd'],
         ['a'],
diff --git a/core/tests/Drupal/Tests/Component/Diff/Engine/DiffOpTest.php b/core/tests/Drupal/Tests/Component/Diff/Engine/DiffOpTest.php
index cde9a30..4752ea3 100644
--- a/core/tests/Drupal/Tests/Component/Diff/Engine/DiffOpTest.php
+++ b/core/tests/Drupal/Tests/Component/Diff/Engine/DiffOpTest.php
@@ -26,9 +26,9 @@ class DiffOpTest extends \PHPUnit_Framework_TestCase {
    * DiffOp::reverse() always throws an error.
    *
    * @covers ::reverse
-   * @expectedException \PHPUnit_Framework_Error
    */
   public function testReverse() {
+    $this->setExpectedException(\PHPUnit_Framework_Error::class);
     $op = new DiffOp();
     $result = $op->reverse();
   }