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

- Refactor: Fix wrong index and adapt tests accordingly

Author: loginesta

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

@@ -4,10 +4,10 @@
 //  */
 
 .nav {
-    background-color: green
+    background-color: green;
 }
 
 .nav-list {
-    background-color: red
-    color: white
+    background-color: red  ;
+    color: red
 }

Magento2/Tests/Less/SemicolonSpacingUnitTest.php

@@ -13,7 +13,8 @@ class SemicolonSpacingUnitTest extends AbstractLessSniffUnitTestCase
     public function getErrorList()
     {
         return [
-            11 => 1
+            11 => 1,
+            12 => 1
         ];
     }