AC-952: Create unit test for Magento2\Less\SemicolonSpacingSniff check

Magento2/Sniffs/Less/SemicolonSpacingSniff.php

@@ -83,7 +83,7 @@ private function validateSemicolon(File $phpcsFile, $stackPtr, array $tokens, $s
     {
         if ((false === $semicolonPtr || $tokens[$semicolonPtr]['line'] !== $tokens[$stackPtr]['line'])
             && (isset($tokens[$stackPtr - 1]) && !in_array($tokens[$stackPtr - 1]['code'], $this->styleCodesToSkip))
-            && (T_COLON !== $tokens[$stackPtr + 1]['code'])
+            && (T_COLON !== $tokens[$stackPtr]['code'])
         ) {
             $error = 'Style definitions must end with a semicolon';
             $phpcsFile->addError($error, $stackPtr, 'NotAtEnd');

Magento2/Tests/Less/SemicolonSpacingUnitTest.less

@@ -0,0 +1,13 @@
+// /**
+//  * Copyright © Magento, Inc. All rights reserved.
+//  * See COPYING.txt for license details.
+//  */
+
+.nav {
+    background-color: green;
+}
+
+.nav-list {
+    background-color: red  ;
+    color: red
+}

Magento2/Tests/Less/SemicolonSpacingUnitTest.php

@@ -0,0 +1,28 @@
+<?php
+/**
+ * Copyright © Magento. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+namespace Magento2\Tests\Less;
+
+class SemicolonSpacingUnitTest extends AbstractLessSniffUnitTestCase
+{
+    /**
+     * @inheritdoc
+     */
+    public function getErrorList()
+    {
+        return [
+            11 => 1,
+            12 => 1
+        ];
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function getWarningList()
+    {
+        return [];
+    }
+}