Tests: fix testStdIn() methods to work with PHPCS 4.x

PHPCS 4.x removed special test-specific code from the Ruleset class that handled `Config::$sniffs` restrictions differently when `PHP_CODESNIFFER_IN_TESTS` was defined (see PHPCSStandards/PHP_CodeSniffer/ 996).

This caused `testStdIn()` tests that used `$config->standards = array('WordPress')` to attempt loading the entire WordPress standard with all dependencies, resulting in errors about missing standards.

The fix uses minimal ruleset XML files that only include the specific sniff being tested making the test pass with both PHPCS 3.x and 4.x.

Author: rodrigoprimo

WordPress/Tests/Files/FileNameStdInTest.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0"?>
+<ruleset xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="FileNameStdInTest" xsi:noNamespaceSchemaLocation="https://schema.phpcodesniffer.com/phpcs.xsd">
+	<description>Ruleset for testing FileName with STDIN.</description>
+
+	<rule ref="WordPress.Files.FileName"/>
+
+</ruleset>

WordPress/Tests/Files/FileNameUnitTest.php

@@ -185,8 +185,7 @@ public function getWarningList() {
 	public function testStdIn() {
 		$config = new ConfigDouble();
 		Helper::setConfigData( 'installed_paths', dirname( dirname( __DIR__ ) ), true, $config );
-		$config->standards = array( 'WordPress' );
-		$config->sniffs    = array( 'WordPress.Files.FileName' );
+		$config->standards = array( __DIR__ . '/FileNameStdInTest.xml' );
 
 		$ruleset = new Ruleset( $config );
 

WordPress/Tests/Utils/I18nTextDomainFixerStdInTest.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0"?>
+<ruleset xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="I18nTextDomainFixerStdInTest" xsi:noNamespaceSchemaLocation="https://schema.phpcodesniffer.com/phpcs.xsd">
+	<description>Ruleset for testing I18nTextDomainFixer with STDIN.</description>
+
+	<rule ref="WordPress.Utils.I18nTextDomainFixer"/>
+
+</ruleset>

WordPress/Tests/Utils/I18nTextDomainFixerUnitTest.php

@@ -214,8 +214,7 @@ public function getWarningList( $testFile = '' ) {
 	public function testStdIn() {
 		$config = new ConfigDouble();
 		Helper::setConfigData( 'installed_paths', dirname( dirname( __DIR__ ) ), true, $config );
-		$config->standards = array( 'WordPress' );
-		$config->sniffs    = array( 'WordPress.Utils.I18nTextDomainFixer' );
+		$config->standards = array( __DIR__ . '/I18nTextDomainFixerStdInTest.xml' );
 
 		$ruleset = new Ruleset( $config );