BCTokens: polyfill the tokenName() method

PHPCSUtils/BackCompat/BCTokens.php

@@ -460,4 +460,30 @@ public static function magicConstants()
 
         return Collections::$magicConstants;
     }
+
+    /**
+     * Given a token, returns the name of the token.
+     *
+     * If passed an integer, the token name is sourced from PHP's token_name()
+     * function. If passed a string, it is assumed to be a PHPCS-supplied token
+     * that begins with PHPCS_T_, so the name is sourced from the token value itself.
+     *
+     * Changelog for the PHPCS native:
+     * - Introduced in PHPCS 3.0.0.
+     *
+     * @see \PHP_CodeSniffer\Util\Tokens::tokenName() Original function.
+     *
+     * @param int|string $token The token to get the name for.
+     *
+     * @return string
+     */
+    public static function tokenName($token)
+    {
+        if (\is_string($token) === false) {
+            // PHP-supplied token name.
+            return \token_name($token);
+        }
+
+        return \substr($token, 6);
+    }
 }

Tests/BackCompat/BCTokens/TokenNameTest.php

@@ -0,0 +1,71 @@
+<?php
+/**
+ * PHPCSUtils, utility functions and classes for PHP_CodeSniffer sniff developers.
+ *
+ * @package   PHPCSUtils
+ * @copyright 2019-2020 PHPCSUtils Contributors
+ * @license   https://opensource.org/licenses/LGPL-3.0 LGPL3
+ * @link      https://github.com/PHPCSStandards/PHPCSUtils
+ */
+
+namespace PHPCSUtils\Tests\BackCompat\BCTokens;
+
+use PHPCSUtils\BackCompat\BCTokens;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Test class.
+ *
+ * @covers \PHPCSUtils\BackCompat\BCTokens::tokenName
+ *
+ * @group tokens
+ *
+ * @since 1.0.0
+ */
+class TokenNameTest extends TestCase
+{
+
+    /**
+     * Test the method.
+     *
+     * @dataProvider dataTokenName
+     *
+     * @param int|string $tokenCode The PHP/PHPCS token code to get the name for.
+     * @param string     $expected  The expected token name.
+     *
+     * @return void
+     */
+    public function testTokenName($tokenCode, $expected)
+    {
+        $this->assertSame($expected, BCTokens::tokenName($tokenCode));
+    }
+
+    /**
+     * Data provider.
+     *
+     * @see testTokenName() For the array format.
+     *
+     * @return array
+     */
+    public function dataTokenName()
+    {
+        return [
+            'PHP native token: T_COMMA' => [
+                \T_COMMA,
+                'T_COMMA',
+            ],
+            'PHP native token: T_SELF' => [
+                \T_SELF,
+                'T_SELF',
+            ],
+            'PHPCS native token: T_CLOSURE' => [
+                \T_CLOSURE,
+                'T_CLOSURE',
+            ],
+            'PHPCS native token: T_STRING_CONCAT' => [
+                \T_STRING_CONCAT,
+                'T_STRING_CONCAT',
+            ],
+        ];
+    }
+}