419 - Test coverage: GetAvailablePaymentMethodsTest for Customer

1. Add testGetPaymentMethodsIfPaymentsAreNotSet and appropriate fixtures

dev/tests/api-functional/testsuite/Magento/GraphQl/Quote/Customer/GetAvailablePaymentMethodsTest.php

@@ -85,6 +85,18 @@ public function testGetPaymentMethodsFromAnotherCustomerCart()
         $this->graphQlQuery($query, [], '', $this->getHeaderMap('customer3@search.example.com'));
     }
 
+    /**
+     * @magentoApiDataFixture Magento/Checkout/_files/quote_with_items_saved.php
+     * @magentoApiDataFixture Magento/Payment/_files/disable_all_active_payment_methods.php
+     */
+    public function testGetPaymentMethodsIfPaymentsAreNotSet()
+    {
+        $maskedQuoteId = $this->getMaskedQuoteIdByReservedOrderId('test_order_item_with_items');
+        $query         = $this->getCartAvailablePaymentMethodsQuery($maskedQuoteId);
+        $response      = $this->graphQlQuery($query, [], '', $this->getHeaderMap());
+
+        self::assertEquals(0, count($response['cart']['available_payment_methods']));
+    }
 
     /**
      * @magentoApiDataFixture Magento/Customer/_files/customer.php

dev/tests/integration/testsuite/Magento/Payment/_files/disable_all_active_payment_methods.php

@@ -0,0 +1,37 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+use Magento\Config\Model\Config;
+use Magento\Framework\App\Config\ScopeConfigInterface;
+use Magento\TestFramework\Helper\Bootstrap;
+
+$processConfigData = function (Config $config, array $data) {
+    foreach ($data as $key => $value) {
+        $config->setDataByPath($key, $value);
+        $config->save();
+    }
+};
+
+$objectManager          = Bootstrap::getObjectManager();
+$paymentMethodList      = $objectManager->get(\Magento\Payment\Api\PaymentMethodListInterface::class);
+$rollbackConfigKey      = 'test/payment/disabled_payment_methods';
+$configData             = [];
+$disabledPaymentMethods = [];
+
+// Get all active Payment Methods
+foreach ($paymentMethodList->getActiveList(\Magento\Store\Model\Store::DEFAULT_STORE_ID) as $paymentMethod) {
+    $configData['payment/' . $paymentMethod->getCode() . '/active'] = 0;
+    $disabledPaymentMethods[] = $paymentMethod->getCode();
+}
+// Remember all manually disabled Payment Methods for rollback
+$configData[$rollbackConfigKey] = implode(',', $disabledPaymentMethods);
+
+/** @var Config $defConfig */
+$defConfig = $objectManager->create(Config::class);
+$defConfig->setScope(ScopeConfigInterface::SCOPE_TYPE_DEFAULT);
+
+$processConfigData($defConfig, $configData);

dev/tests/integration/testsuite/Magento/Payment/_files/disable_all_active_payment_methods_rollback.php

@@ -0,0 +1,33 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+use Magento\Framework\App\Config\ScopeConfigInterface;
+use Magento\Framework\App\Config\Storage\WriterInterface;
+use Magento\TestFramework\Helper\Bootstrap;
+
+$objectManager     = Bootstrap::getObjectManager();
+$rollbackConfigKey = 'test/payment/disabled_payment_methods';
+
+$configWriter        = $objectManager->create(WriterInterface::class);
+$rollbackConfigValue = $objectManager->get(\Magento\Store\Model\StoreManagerInterface::class)
+    ->getStore(\Magento\Store\Model\Store::DEFAULT_STORE_ID)
+    ->getConfig($rollbackConfigKey);
+
+$disabledPaymentMethods = [];
+if (!empty($rollbackConfigValue)) {
+    $disabledPaymentMethods = explode(',', $rollbackConfigValue);
+}
+
+if (count($disabledPaymentMethods)) {
+    foreach ($disabledPaymentMethods as $keyToRemove) {
+        $configWriter->delete(sprintf('payment/%s/active', $keyToRemove));
+    }
+}
+$configWriter->delete($rollbackConfigKey);
+
+$scopeConfig = $objectManager->get(ScopeConfigInterface::class);
+$scopeConfig->clean();