refactor: added readonly lazy loading test

Author: NickSdot

Zend/tests/property_hooks/readonly_lazy.phpt

@@ -0,0 +1,60 @@
+--TEST--
+Hooks work on backed readonly properties
+--FILE--
+<?php
+
+interface DbConnection {
+   public function loadCategory(string $id): Category;
+}
+
+class Category {
+   public function __construct(public string $name) {}
+}
+
+class MockDbConnection implements DbConnection {
+   public function loadCategory(string $id): Category {
+       echo "hit database\n";
+       return new Category("Category {$id}");
+   }
+}
+
+readonly class LazyProduct
+{
+   private DbConnection $dbApi;
+   private string $categoryId;
+
+   public Category $category {
+       get {
+           return $this->category ??= $this->dbApi->loadCategory($this->categoryId);
+       }
+   }
+}
+
+$product = new LazyProduct();
+$reflect = new ReflectionClass($product);
+
+$db = $reflect->getProperty('dbApi');
+$db->setAccessible(true);
+$db->setValue($product, new MockDbConnection());
+
+$categoryId = $reflect->getProperty('categoryId');
+$categoryId->setAccessible(true);
+$categoryId->setValue($product, '42');
+
+// lazy loading, hit db
+$category1 = $product->category;
+echo $category1->name . "\n";
+
+// cached value
+$category2 = $product->category;
+echo $category2->name . "\n";
+
+// Verify same instance is returned (backing field caching works)
+var_dump($category1 === $category2);
+
+?>
+--EXPECT--
+hit database
+Category 42
+Category 42
+bool(true)