diff --git a/src/Framework/Constraint/Operator/LogicalNot.php b/src/Framework/Constraint/Operator/LogicalNot.php
index 86635a1ea51..aca799c3d79 100644
--- a/src/Framework/Constraint/Operator/LogicalNot.php
+++ b/src/Framework/Constraint/Operator/LogicalNot.php
@@ -49,6 +49,7 @@ public static function negate(string $string): string
         ];
 
         preg_match('/(\'[\w\W]*\')([\w\W]*)("[\w\W]*")/i', $string, $matches);
+
         if (count($matches) === 0) {
             preg_match('/(\'[\w\W]*\')([\w\W]*)(\'[\w\W]*\')/i', $string, $matches);
         }
diff --git a/tests/unit/Framework/Assert/AssertNotEqualsTest.php b/tests/unit/Framework/Assert/AssertNotEqualsTest.php
index 499d3f7b344..45466e0aff2 100644
--- a/tests/unit/Framework/Assert/AssertNotEqualsTest.php
+++ b/tests/unit/Framework/Assert/AssertNotEqualsTest.php
@@ -1,21 +1,30 @@
-<?php
-
+<?php declare(strict_types=1);
+/*
+ * This file is part of PHPUnit.
+ *
+ * (c) Sebastian Bergmann <sebastian@phpunit.de>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
 namespace PHPUnit\Framework;
 
+use Exception;
 use PHPUnit\Framework\Constraint\IsEqual;
 use PHPUnit\Framework\Constraint\LogicalNot;
 
 class AssertNotEqualsTest extends TestCase
 {
-    public function testConfusingMessagesForLogicalNot()
+    public function testConfusingMessagesForLogicalNot(): void
     {
         $expectedMessage = "Failed asserting that 'test contains something' is not equal to 'test contains something'.";
-        $a = 'test contains something';
-        $b = 'test contains something';
-        $constraint = new LogicalNot(new IsEqual($a));
+        $a               = 'test contains something';
+        $b               = 'test contains something';
+        $constraint      = new LogicalNot(new IsEqual($a));
+
         try {
             Assert::assertThat($b, $constraint);
-        } catch (\Exception $e) {
+        } catch (Exception $e) {
             $actualMessage = $e->getMessage();
             $this->assertSame($expectedMessage, $actualMessage);
         }