Build/Test Tools: Check if PHPUnit classes exist before calling class_alias().

This resolves `Class not found` warnings when running the tests in PHPUnit 10 or later.

Follow-up to [40536], [51570].

Props danielmorell, devasheeshkaul, SergeyBiryukov.
Fixes #63833.

git-svn-id: https://develop.svn.wordpress.org/trunk@60693 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

tests/phpunit/includes/phpunit6/compat.php

@@ -2,20 +2,26 @@
 
 if ( class_exists( 'PHPUnit\Runner\Version' ) && version_compare( PHPUnit\Runner\Version::id(), '6.0', '>=' ) ) {
 
-	class_alias( 'PHPUnit\Framework\TestCase', 'PHPUnit_Framework_TestCase' );
-	class_alias( 'PHPUnit\Framework\Exception', 'PHPUnit_Framework_Exception' );
-	class_alias( 'PHPUnit\Framework\ExpectationFailedException', 'PHPUnit_Framework_ExpectationFailedException' );
-	class_alias( 'PHPUnit\Framework\Error\Deprecated', 'PHPUnit_Framework_Error_Deprecated' );
-	class_alias( 'PHPUnit\Framework\Error\Notice', 'PHPUnit_Framework_Error_Notice' );
-	class_alias( 'PHPUnit\Framework\Error\Warning', 'PHPUnit_Framework_Error_Warning' );
-	class_alias( 'PHPUnit\Framework\Test', 'PHPUnit_Framework_Test' );
-	class_alias( 'PHPUnit\Framework\Warning', 'PHPUnit_Framework_Warning' );
-	class_alias( 'PHPUnit\Framework\AssertionFailedError', 'PHPUnit_Framework_AssertionFailedError' );
-	class_alias( 'PHPUnit\Framework\TestSuite', 'PHPUnit_Framework_TestSuite' );
-	class_alias( 'PHPUnit\Framework\TestListener', 'PHPUnit_Framework_TestListener' );
-	class_alias( 'PHPUnit\Util\GlobalState', 'PHPUnit_Util_GlobalState' );
-	if ( class_exists( 'PHPUnit\Util\Getopt' ) ) {
-		class_alias( 'PHPUnit\Util\Getopt', 'PHPUnit_Util_Getopt' );
+	$aliases = array(
+		'PHPUnit\Framework\TestCase'                   => 'PHPUnit_Framework_TestCase',
+		'PHPUnit\Framework\Exception'                  => 'PHPUnit_Framework_Exception',
+		'PHPUnit\Framework\ExpectationFailedException' => 'PHPUnit_Framework_ExpectationFailedException',
+		'PHPUnit\Framework\Error\Deprecated'           => 'PHPUnit_Framework_Error_Deprecated',
+		'PHPUnit\Framework\Error\Notice'               => 'PHPUnit_Framework_Error_Notice',
+		'PHPUnit\Framework\Error\Warning'              => 'PHPUnit_Framework_Error_Warning',
+		'PHPUnit\Framework\Test'                       => 'PHPUnit_Framework_Test',
+		'PHPUnit\Framework\Warning'                    => 'PHPUnit_Framework_Warning',
+		'PHPUnit\Framework\AssertionFailedError'       => 'PHPUnit_Framework_AssertionFailedError',
+		'PHPUnit\Framework\TestSuite'                  => 'PHPUnit_Framework_TestSuite',
+		'PHPUnit\Framework\TestListener'               => 'PHPUnit_Framework_TestListener',
+		'PHPUnit\Util\GlobalState'                     => 'PHPUnit_Util_GlobalState',
+		'PHPUnit\Util\Getopt'                          => 'PHPUnit_Util_Getopt',
+	);
+
+	foreach ( $aliases as $original => $alias ) {
+		if ( class_exists( $original ) ) {
+			class_alias( $original, $alias );
+		}
 	}
 
 	class PHPUnit_Util_Test {