graphQl-533: fixed set purchase order

Author: Vitaliy Boyko

app/code/Magento/QuoteGraphQl/Model/Resolver/SetPaymentMethodOnCart.php

@@ -69,10 +69,7 @@ public function resolve(Field $field, $context, ResolveInfo $info, array $value
         }
         $paymentMethodCode = $args['input']['payment_method']['code'];
 
-        $poNumber = isset($args['input']['payment_method']['purchase_order_number'])
-            && empty($args['input']['payment_method']['purchase_order_number'])
-            ? $args['input']['payment_method']['purchase_order_number']
-            : null;
+        $poNumber = $args['input']['payment_method']['purchase_order_number'] ?? null;
 
         $cart = $this->getCartForUser->execute($maskedCartId, $context->getUserId());
         $payment = $this->paymentFactory->create([

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

@@ -60,6 +60,44 @@ public function testSetPaymentOnCartWithSimpleProduct()
         self::assertEquals($methodCode, $response['setPaymentMethodOnCart']['cart']['selected_payment_method']['code']);
     }
 
+    /**
+     * @magentoApiDataFixture Magento/Customer/_files/customer.php
+     * @magentoApiDataFixture Magento/GraphQl/Catalog/_files/simple_product.php
+     * @magentoApiDataFixture Magento/GraphQl/Quote/_files/customer/create_empty_cart.php
+     * @magentoApiDataFixture Magento/GraphQl/Quote/_files/add_simple_product.php
+     * @magentoApiDataFixture Magento/GraphQl/Quote/_files/set_new_shipping_address.php
+     * @magentoApiDataFixture Magento/GraphQl/Quote/_files/enable_offline_payment_methods.php
+     */
+    public function testSetPurchaseOrderPaymentMethodOnCartWithSimpleProduct()
+    {
+        $methodCode = Checkmo::PAYMENT_METHOD_CHECKMO_CODE;
+        $maskedQuoteId = $this->getMaskedQuoteIdByReservedOrderId->execute('test_quote');
+
+        $query = <<<QUERY
+mutation {
+  setPaymentMethodOnCart(input: {
+      cart_id: "$maskedQuoteId"
+      payment_method: {
+          code: "$methodCode",
+          purchase_order_number: "123456"
+      }
+  }) {    
+    cart {
+      selected_payment_method {
+        code
+      }
+    }
+  }
+}
+QUERY;
+        $response = $this->graphQlQuery($query, [], '', $this->getHeaderMap());
+
+        self::assertArrayHasKey('setPaymentMethodOnCart', $response);
+        self::assertArrayHasKey('cart', $response['setPaymentMethodOnCart']);
+        self::assertArrayHasKey('selected_payment_method', $response['setPaymentMethodOnCart']['cart']);
+        self::assertEquals($methodCode, $response['setPaymentMethodOnCart']['cart']['selected_payment_method']['code']);
+    }
+
     /**
      * @magentoApiDataFixture Magento/Customer/_files/customer.php
      * @magentoApiDataFixture Magento/GraphQl/Catalog/_files/simple_product.php

dev/tests/api-functional/testsuite/Magento/GraphQl/Quote/Guest/SetPaymentMethodOnCartTest.php

@@ -10,6 +10,7 @@
 use Magento\GraphQl\Quote\GetMaskedQuoteIdByReservedOrderId;
 use Magento\OfflinePayments\Model\Cashondelivery;
 use Magento\OfflinePayments\Model\Checkmo;
+use Magento\OfflinePayments\Model\Purchaseorder;
 use Magento\TestFramework\Helper\Bootstrap;
 use Magento\TestFramework\TestCase\GraphQlAbstract;
 
@@ -52,6 +53,43 @@ public function testSetPaymentOnCartWithSimpleProduct()
         self::assertEquals($methodCode, $response['setPaymentMethodOnCart']['cart']['selected_payment_method']['code']);
     }
 
+    /**
+     * @magentoApiDataFixture Magento/GraphQl/Catalog/_files/simple_product.php
+     * @magentoApiDataFixture Magento/GraphQl/Quote/_files/guest/create_empty_cart.php
+     * @magentoApiDataFixture Magento/GraphQl/Quote/_files/add_simple_product.php
+     * @magentoApiDataFixture Magento/GraphQl/Quote/_files/set_new_shipping_address.php
+     * @magentoApiDataFixture Magento/GraphQl/Quote/_files/enable_offline_payment_methods.php
+     */
+    public function testSetPurchaseOrderPaymentMethodOnCartWithSimpleProduct()
+    {
+        $methodCode = Purchaseorder::PAYMENT_METHOD_PURCHASEORDER_CODE;
+        $maskedQuoteId = $this->getMaskedQuoteIdByReservedOrderId->execute('test_quote');
+
+        $query = <<<QUERY
+mutation {
+  setPaymentMethodOnCart(input: {
+    cart_id: "{$maskedQuoteId}", 
+    payment_method: {
+      code: "{$methodCode}",
+      purchase_order_number: "123456"
+    }
+  }) {
+    cart {
+      selected_payment_method {
+        code
+      }
+    }
+  }
+}
+QUERY;
+        $response = $this->graphQlQuery($query);
+
+        self::assertArrayHasKey('setPaymentMethodOnCart', $response);
+        self::assertArrayHasKey('cart', $response['setPaymentMethodOnCart']);
+        self::assertArrayHasKey('selected_payment_method', $response['setPaymentMethodOnCart']['cart']);
+        self::assertEquals($methodCode, $response['setPaymentMethodOnCart']['cart']['selected_payment_method']['code']);
+    }
+
     /**
      * @magentoApiDataFixture Magento/GraphQl/Catalog/_files/simple_product.php
      * @magentoApiDataFixture Magento/GraphQl/Quote/_files/guest/create_empty_cart.php