如何在 php-unit 中模拟 Mage::getSingleton('checkout/cart') ？

Question

我有这个 foo() 方法，我需要在 Magento 中为此方法 testFoo() 添加单元测试用例。但无法模拟 Mage::getSingleton('checkout/cart')。

来源方法

public function foo()
{
    return Mage::getSingleton('checkout/cart')->getQuote()->getFunctionName();
}

测试功能

public function testFoo(): void
{
    //$this->className :: Project_Catalog_Helper_Test
    $expected = 'string';
    $this->className->method('getSingleton')->willReturn($this->cart);
    $this->cart->method('getQuote')->willReturn($this->cart);
    $this->cart->method('getFunctionName')->willReturn('string');
    $this->assertEquals(
        $this->className->foo(),
        $expected
    );
}

当我运行时，php-unit 收到此错误日志。

MacBook-Pro % ./vendor/bin/phpunit tests/src/app/code/local/project/Catalog/Helper/OrderTest.php
PHPUnit 6.5.14 by Sebastian Bergmann and contributors.

Runtime:       PHP 7.3.11
Configuration: /project_path/phpunit.xml.dist

E                                                                   1 / 1 (100%)

Time: 150 ms, Memory: 8.00MB

There was 1 error:

1) Project_Catalog_Helper_Test::testFoo
Error: Call to a member function getCode() on bool

/project_path/app/code/core/Mage/Customer/Model/Session.php:103
/project_path/app/code/core/Mage/Core/Model/Config.php:1394
/project_path/app/Mage.php:517
/project_path/app/Mage.php:531
/project_path/app/code/community/Checkout/Model/Cart.php:20
/project_path/app/code/local/project/Catalog/Helper/Order.php:21
/project_path/tests/src/app/code/local/project/Catalog/Helper/OrderTest.php:100
/project_path/vendor/phpunit/phpunit/phpunit:53

需要一些解决方案，如何模拟 Mage::getSingleton('checkout/cart')。

注意：我无法更改 main 方法，因为它是遗留代码。只需添加单元测试用例。

Answer 1

您不能模拟 Mage::getSingleton('checkout/cart')，因为它是全局命名空间中的静态函数。

但是，您可以使用元编程注入结账卡模拟来注入模拟。然后在该位置恢复原来的单例。

与继承自 EComDev Testsuite 的现有问答进行比较，该问答应该具有更多指针如何使用 PHP Reflection 处理内部结构。