From 604225c3c8fa816219f1420733cb270648c2bddd Mon Sep 17 00:00:00 2001
From: Nabeel Molham <72820458+nmolham-godaddy@users.noreply.github.com>
Date: Fri, 23 Aug 2024 20:37:49 +1000
Subject: [PATCH] Add IsSingletonTrait (#700)

* Define IsSingletonTrait

* Add IsSingletonTrait methods

* Unit test IsSingletonTrait

* Add changelog entry

* Check if trait exists rather than class

---------

Co-authored-by: Ashley Gibson <99189195+agibson-godaddy@users.noreply.github.com>
---
 tests/bootstrap.php                        |  1 +
 tests/unit/Traits/IsSingletonTraitTest.php | 78 ++++++++++++++++++++++
 woocommerce/Traits/IsSingletonTrait.php    | 67 +++++++++++++++++++
 woocommerce/changelog.txt                  |  1 +
 4 files changed, 147 insertions(+)
 create mode 100644 tests/unit/Traits/IsSingletonTraitTest.php
 create mode 100644 woocommerce/Traits/IsSingletonTrait.php

diff --git a/tests/bootstrap.php b/tests/bootstrap.php
index b846bcfaf..6cd225bdb 100644
--- a/tests/bootstrap.php
+++ b/tests/bootstrap.php
@@ -9,6 +9,7 @@
 require_once PLUGIN_ROOT_DIR.'/woocommerce/class-sv-wc-plugin-exception.php';
 require_once PLUGIN_ROOT_DIR.'/woocommerce/Enums/Traits/EnumTrait.php';
 require_once PLUGIN_ROOT_DIR.'/woocommerce/Enums/PaymentFormContext.php';
+require_once PLUGIN_ROOT_DIR.'/woocommerce/Traits/IsSingletonTrait.php';
 
 WP_Mock::setUsePatchwork(true);
 WP_Mock::bootstrap();
diff --git a/tests/unit/Traits/IsSingletonTraitTest.php b/tests/unit/Traits/IsSingletonTraitTest.php
new file mode 100644
index 000000000..82f0781c2
--- /dev/null
+++ b/tests/unit/Traits/IsSingletonTraitTest.php
@@ -0,0 +1,78 @@
+<?php
+
+namespace SkyVerge\WooCommerce\PluginFramework\v5_13_1\Tests\Unit\Traits;
+
+use Exception;
+use ReflectionClass;
+use SkyVerge\WooCommerce\PluginFramework\v5_13_1\Tests\TestCase;
+use SkyVerge\WooCommerce\PluginFramework\v5_13_1\Traits\IsSingletonTrait;
+
+class IsSingletonTraitTest extends TestCase
+{
+	protected TestSingleton $singleton;
+
+	/**
+	 * Runs a script for every test in this set.
+	 *
+	 * @throws Exception
+	 */
+	public function setUp() : void
+	{
+		parent::setUp();
+
+		$this->singleton = new TestSingleton();
+
+		$this->setInaccessiblePropertyValue($this->singleton, 'instance', $this->singleton);
+	}
+
+	/**
+	 * Tests that it can determine whether an instance is loaded or not.
+	 *
+	 * @covers \SkyVerge\WooCommerce\PluginFramework\v5_13_1\Traits\IsSingletonTrait::isLoaded()
+	 */
+	public function testCanCheckIfIsLoaded() : void
+	{
+		self::assertTrue($this->singleton::isLoaded());
+
+		$this->singleton::reset();
+
+		self::assertFalse($this->singleton::isLoaded());
+	}
+
+	/**
+	 * Tests that it can initialize and return an instance of self.
+	 *
+	 * @covers \SkyVerge\WooCommerce\PluginFramework\v5_13_1\Traits\IsSingletonTrait::getInstance()
+	 */
+	public function testCanGetInstance() : void
+	{
+		TestSingleton::reset();
+
+		$instance = TestSingleton::getInstance();
+
+		$this->assertInstanceOf(TestSingleton::class, $instance);
+		$this->assertSame($instance, TestSingleton::getInstance());
+	}
+
+	/**
+	 * Tests that an instance can be reset.
+	 *
+	 * @covers \SkyVerge\WooCommerce\PluginFramework\v5_13_1\Traits\IsSingletonTrait::reset()
+	 */
+	public function testCanBeReset() : void
+	{
+		$this->singleton::reset();
+
+		$singleton = new ReflectionClass($this->singleton);
+		$instance = $singleton->getProperty('instance');
+		$instance->setAccessible(true);
+
+		self::assertNull($instance->getValue());
+	}
+}
+
+/** Dummy class for testing {@see IsSingletonTrait} */
+final class TestSingleton
+{
+	use IsSingletonTrait;
+}
diff --git a/woocommerce/Traits/IsSingletonTrait.php b/woocommerce/Traits/IsSingletonTrait.php
new file mode 100644
index 000000000..4d4e93ed6
--- /dev/null
+++ b/woocommerce/Traits/IsSingletonTrait.php
@@ -0,0 +1,67 @@
+<?php
+/**
+ * WooCommerce Plugin Framework
+ *
+ * This source file is subject to the GNU General Public License v3.0
+ * that is bundled with this package in the file license.txt.
+ * It is also available through the world-wide-web at this URL:
+ * http://www.gnu.org/licenses/gpl-3.0.html
+ * If you did not receive a copy of the license and are unable to
+ * obtain it through the world-wide-web, please send an email
+ * to license@skyverge.com so we can send you a copy immediately.
+ *
+ * DISCLAIMER
+ *
+ * Do not edit or add to this file if you wish to upgrade the plugin to newer
+ * versions in the future. If you wish to customize the plugin for your
+ * needs please refer to http://www.skyverge.com
+ *
+ * @package   SkyVerge/WooCommerce/Plugin/Classes
+ * @author    SkyVerge
+ * @copyright Copyright (c) 2013-2024, SkyVerge, Inc.
+ * @license   http://www.gnu.org/licenses/gpl-3.0.html GNU General Public License v3.0
+ */
+
+namespace SkyVerge\WooCommerce\PluginFramework\v5_13_1\Traits;
+
+defined('ABSPATH') or exit;
+
+if (trait_exists('\\SkyVerge\\WooCommerce\\PluginFramework\\v5_13_1\\Traits\\IsSingletonTrait')) {
+	return;
+}
+
+trait IsSingletonTrait
+{
+	/** @var ?static holds the current singleton instance */
+	protected static $instance;
+
+	/**
+	 * Determines if the current instance is loaded.
+	 *
+	 * @return bool
+	 */
+	public static function isLoaded() : bool
+	{
+		return (bool) static::$instance;
+	}
+
+	/**
+	 * Gets the singleton instance.
+	 *
+	 * @return static
+	 */
+	public static function getInstance()
+	{
+		return static::$instance ??= new static(...func_get_args());
+	}
+
+	/**
+	 * Resets the singleton instance.
+	 *
+	 * @return void
+	 */
+	public static function reset() : void
+	{
+		static::$instance = null;
+	}
+}
diff --git a/woocommerce/changelog.txt b/woocommerce/changelog.txt
index 430b7f9b3..6488962e6 100644
--- a/woocommerce/changelog.txt
+++ b/woocommerce/changelog.txt
@@ -1,6 +1,7 @@
 *** SkyVerge WooCommerce Plugin Framework Changelog ***
 
 2024.nn.nn - version 5.13.1-dev.1
+* Feature - Add a trait to get a singular instance of a class IsSingletonTrait
 
 2024.08.21 - version 5.13.0
  * Feature - Add a trait for enum-like classes