Add Backed Enum test case when implementing an interface

Zend/tests/enum/backed-implements-multiple.phpt

@@ -0,0 +1,58 @@
+--TEST--
+Backed Enum with multiple implementing interfaces
+--FILE--
+<?php
+
+interface Colorful {
+    public function color(): string;
+}
+
+interface Shaped {
+    public function shape(): string;
+}
+
+interface ExtendedShaped extends Shaped {
+}
+
+enum Suit: string implements Colorful, ExtendedShaped {
+    case Hearts = 'H';
+    case Diamonds = 'D';
+    case Clubs = 'C';
+    case Spades = 'S';
+
+    public function color(): string {
+        return match ($this) {
+            self::Hearts, self::Diamonds => 'Red',
+            self::Clubs, self::Spades => 'Black',
+        };
+    }
+
+    public function shape(): string {
+        return match ($this) {
+            self::Hearts => 'heart',
+            self::Diamonds => 'diamond',
+            self::Clubs => 'club',
+            self::Spades => 'spade',
+        };
+    }
+}
+
+echo Suit::Hearts->color() . "\n";
+echo Suit::Hearts->shape() . "\n";
+echo Suit::Diamonds->color() . "\n";
+echo Suit::Diamonds->shape() . "\n";
+echo Suit::Clubs->color() . "\n";
+echo Suit::Clubs->shape() . "\n";
+echo Suit::Spades->color() . "\n";
+echo Suit::Spades->shape() . "\n";
+
+?>
+--EXPECT--
+Red
+heart
+Red
+diamond
+Black
+club
+Black
+spade

Zend/tests/enum/backed-implements.phpt

@@ -0,0 +1,34 @@
+--TEST--
+Backed Enum implements
+--FILE--
+<?php
+
+interface Colorful {
+    public function color(): string;
+}
+
+enum Suit: string implements Colorful {
+    case Hearts = 'H';
+    case Diamonds = 'D';
+    case Clubs = 'C';
+    case Spades = 'S';
+
+    public function color(): string {
+        return match ($this) {
+            self::Hearts, self::Diamonds => 'Red',
+            self::Clubs, self::Spades => 'Black',
+        };
+    }
+}
+
+echo Suit::Hearts->color() . "\n";
+echo Suit::Diamonds->color() . "\n";
+echo Suit::Clubs->color() . "\n";
+echo Suit::Spades->color() . "\n";
+
+?>
+--EXPECT--
+Red
+Red
+Black
+Black