From 5d4e03eb2a444d36d2a28fd054e8618a3778d282 Mon Sep 17 00:00:00 2001
From: Clement <clement.gutel@gmail.com>
Date: Mon, 28 Nov 2022 10:12:47 +1100
Subject: [PATCH] Ensure that LineItem.TipPaymentGateway is always deserialized
 so that the TipPaymentGatewaySpecified property gets set.

---
 ShopifySharp.Tests/Order_Tests.cs | 18 ++++++++++++++++++
 ShopifySharp/Entities/LineItem.cs |  2 +-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/ShopifySharp.Tests/Order_Tests.cs b/ShopifySharp.Tests/Order_Tests.cs
index 5451cb2a..f0d56a21 100644
--- a/ShopifySharp.Tests/Order_Tests.cs
+++ b/ShopifySharp.Tests/Order_Tests.cs
@@ -205,6 +205,24 @@ public async Task Can_Be_Partially_Updated()
             // In previous versions of ShopifySharp, the updated JSON would have sent 'email=null', clearing out the email address.
             Assert.Equal(created.Email, updated.Email);
         }
+
+        [Fact]
+        public void TipPaymentGatewaySpecified_GetDeserialized()
+        {
+            string orderJson = @"{
+  ""id"": 123,
+  ""line_items"": [
+    {
+      ""id"": 123,
+      ""tip_payment_gateway"": null
+    }
+  ]
+}
+";
+            var order = Infrastructure.Serializer.Deserialize<Order>(orderJson);
+            Assert.Null(order.LineItems.First().TipPaymentGateway);
+            Assert.True(order.LineItems.First().TipPaymentGatewaySpecified);
+        }
     }
 
     public class Order_Tests_Fixture : IAsyncLifetime
diff --git a/ShopifySharp/Entities/LineItem.cs b/ShopifySharp/Entities/LineItem.cs
index 0f876053..7fcc6aaa 100644
--- a/ShopifySharp/Entities/LineItem.cs
+++ b/ShopifySharp/Entities/LineItem.cs
@@ -118,7 +118,7 @@ public class LineItem : ShopifyObject
         /// <summary>
         /// The payment gateway used to tender the tip, such as shopify_payments. Present only on tips.
         /// </summary>
-        [JsonProperty("tip_payment_gateway")]
+        [JsonProperty("tip_payment_gateway", NullValueHandling = NullValueHandling.Include)]
         public string TipPaymentGateway { get; set; }
 
         /// <summary>