AC-1156: Move custom eslint tests to magento-coding-standard repo

- Add strict types and phpdocs

Author: loginesta

Magento2/Tests/Eslint/AbstractEslintTestCase.php

@@ -3,12 +3,23 @@
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
+declare(strict_types=1);
+
 namespace Magento2\Tests\Eslint;
 
 use PHPUnit\Framework\TestCase;
 
+/**
+ * Abstract class AbstractEslintTestCase
+ *
+ * Test Eslint Rules (magento-coding-standard/eslint/rules)
+ */
 abstract class AbstractEslintTestCase extends TestCase
 {
+    /**
+     * @param string $testFile
+     * @param array $expectedMessages
+     */
     protected function assertFileContainsError(string $testFile, array $expectedMessages)
     {
         exec(