Add postcode validation for Slovenia (woocommerce#25174)

Add postcode validation for Slovenia

Author: R33D3M33R

includes/class-wc-validation.php

@@ -96,7 +96,9 @@ public static function is_postcode( $postcode, $country ) {
 			case 'NL':
 				$valid = (bool) preg_match( '/^([1-9][0-9]{3})(\s?)(?!SA|SD|SS)[A-Z]{2}$/i', $postcode );
 				break;
-
+			case 'SI':
+				$valid = (bool) preg_match( '/^([1-9][0-9]{3})$/', $postcode );
+				break;
 			default:
 				$valid = true;
 				break;

tests/unit-tests/util/validation.php

@@ -107,7 +107,15 @@ public function data_provider_test_is_postcode() {
 			array( false, WC_Validation::is_postcode( '3852 sa', 'NL' ) ),
 		);
 
-		return array_merge( $it, $gb, $us, $ch, $br, $ca, $nl );
+		$si = array(
+			array( true, WC_Validation::is_postcode( '1234', 'SI' ) ),
+			array( true, WC_Validation::is_postcode( '1000', 'SI' ) ),
+			array( true, WC_Validation::is_postcode( '9876', 'SI' ) ),
+			array( false, WC_Validation::is_postcode( '12345', 'SI' ) ),
+			array( false, WC_Validation::is_postcode( '0123', 'SI' ) ),
+		);
+
+		return array_merge( $it, $gb, $us, $ch, $br, $ca, $nl, $si );
 	}
 
 	/**