diff --git a/core/tests/Drupal/Tests/Component/Diff/Engine/DiffEngineTest.php b/core/tests/Drupal/Tests/Component/Diff/Engine/DiffEngineTest.php
index 80f2093..79a28ef 100644
--- a/core/tests/Drupal/Tests/Component/Diff/Engine/DiffEngineTest.php
+++ b/core/tests/Drupal/Tests/Component/Diff/Engine/DiffEngineTest.php
@@ -31,11 +31,11 @@ class DiffEngineTest extends \PHPUnit_Framework_TestCase {
    */
   public function provideTestDiff() {
     return [
-      [[], [], []],
-      [[DiffOpAdd::class], [], ['a']],
-      [[DiffOpCopy::class], ['a'], ['a']],
-      [[DiffOpChange::class], ['a'], ['b']],
-      [
+      'empty' => [[], [], []],
+      'add' => [[DiffOpAdd::class], [], ['a']],
+      'copy' => [[DiffOpCopy::class], ['a'], ['a']],
+      'change' => [[DiffOpChange::class], ['a'], ['b']],
+      'copy-and-change' => [
         [
           DiffOpCopy::class,
           DiffOpChange::class,
@@ -43,7 +43,7 @@ public function provideTestDiff() {
         ['a', 'b'],
         ['a', 'c'],
       ],
-      [
+      'copy-change-copy' => [
         [
           DiffOpCopy::class,
           DiffOpChange::class,
@@ -52,7 +52,7 @@ public function provideTestDiff() {
         ['a', 'b', 'd'],
         ['a', 'c', 'd'],
       ],
-      [
+      'copy-change-copy-add' => [
         [
           DiffOpCopy::class,
           DiffOpChange::class,
@@ -62,7 +62,7 @@ public function provideTestDiff() {
         ['a', 'b', 'd'],
         ['a', 'c', 'd', 'e'],
       ],
-      [
+      'copy-delete' => [
         [
           DiffOpCopy::class,
           DiffOpDelete::class,