Fix tests failing on PHP 7.1

includes/class-syndication-encryption.php

@@ -26,8 +26,9 @@ public static function get_encryptor() {
 			return self::$encryptor;
 		}
 
-		// If mcrypt is available ( PHP < 7.1 ), use it instead.
-		if ( defined( 'MCRYPT_RIJNDAEL_256' ) ) {
+		// On PHP 7.1 mcrypt is available, but will throw a deprecated error if its used. Therefore, checking for the
+		// PHP version, instead of checking for mcrypt is a better approach.
+		if ( version_compare( PHP_VERSION, '7.1', '<' ) ) {
 			self::$encryptor = new Syndication_Encryptor_MCrypt();
 			return self::$encryptor;
 		}

tests/test-encryption.php

@@ -121,9 +121,12 @@ public function test_encryptor_openssl() {
 	 * @requires extension mcrypt
 	 */
 	public function test_encryptor_mcrypt() {
-		$encryptor = new \Syndication_Encryptor_MCrypt();
-
+		// Disable deprecation warning for this test, as it will run on PHP 7.1. This test will only ensure functionality of the
+		// Syndication_Encryptor_MCrypt class.
+		// phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.runtime_configuration_error_reporting
+		$error_reporting = error_reporting( error_reporting() & ~E_DEPRECATED );
 
+		$encryptor = new \Syndication_Encryptor_MCrypt();
 
 		// Test the cipher.
 		$expected_cipher = MCRYPT_RIJNDAEL_256; // phpcs:ignore PHPCompatibility.Constants.RemovedConstants.mcrypt_rijndael_256DeprecatedRemoved
@@ -136,6 +139,9 @@ public function test_encryptor_mcrypt() {
 
 		$decrypted = $encryptor->decrypt( $encrypted );
 		self::assertEquals( $this->simple_string, $decrypted );
+
+		// Restore original error reporting.
+		error_reporting( $error_reporting ); // phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.runtime_configuration_error_reporting
 	}