From ea6f7f86c02c1acd00a8ef365ff99c063e8d5b4f Mon Sep 17 00:00:00 2001
From: Kennedy Kangethe <kemunga@microsoft.com>
Date: Wed, 22 Sep 2021 17:20:01 +0300
Subject: [PATCH] Add test

---
 .../ODataNestedResourceInfo.cs                |  4 ++--
 ...nstanceAnnotationWriterIntegrationTests.cs | 20 +++++++++++++++++++
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/src/Microsoft.OData.Core/ODataNestedResourceInfo.cs b/src/Microsoft.OData.Core/ODataNestedResourceInfo.cs
index dd8b1c7e66..bee3eb6e1f 100644
--- a/src/Microsoft.OData.Core/ODataNestedResourceInfo.cs
+++ b/src/Microsoft.OData.Core/ODataNestedResourceInfo.cs
@@ -36,7 +36,7 @@ public sealed class ODataNestedResourceInfo : ODataItem
         private bool hasAssociationUrl;
 
         /// <summary>The number of items in the resource set.</summary>
-        private long count;
+        private long? count;
 
         /// <summary>Gets or sets a value that indicates whether the nested resource info represents a collection or a resource.</summary>
         /// <returns>true if the nested resource info represents a collection; false if the navigation represents a resource.</returns>
@@ -113,7 +113,7 @@ public long? Count
                     throw new ODataException(Strings.ODataWriterCore_QueryCountInODataNestedResourceInfo);
                 }
 
-                this.count = (long)value;
+                this.count = value;
             }
         }
 
diff --git a/test/FunctionalTests/Microsoft.OData.Core.Tests/IntegrationTests/Writer/InstanceAnnotationWriterIntegrationTests.cs b/test/FunctionalTests/Microsoft.OData.Core.Tests/IntegrationTests/Writer/InstanceAnnotationWriterIntegrationTests.cs
index 43466e370d..968dd6d878 100644
--- a/test/FunctionalTests/Microsoft.OData.Core.Tests/IntegrationTests/Writer/InstanceAnnotationWriterIntegrationTests.cs
+++ b/test/FunctionalTests/Microsoft.OData.Core.Tests/IntegrationTests/Writer/InstanceAnnotationWriterIntegrationTests.cs
@@ -583,6 +583,26 @@ public void WriteAnnotationAndCountAtStartExpandedFeedShouldPassInJsonLight()
 
             this.WriteAnnotationsAndValidatePayload(action, EntitySet, ODataFormat.Json, expectedPayload, request: false, createFeedWriter: false);
         }
+
+        [Fact]
+        public void WriteCountOnExpandedEntryShouldFail()
+        {
+            Action<ODataWriter> action = (odataWriter) =>
+            {
+                var entryToWrite = new ODataResource { Properties = new[] { new ODataProperty { Name = "ID", Value = 1 } } };
+                odataWriter.WriteStart(entryToWrite);
+
+                ODataNestedResourceInfo navLink = new ODataNestedResourceInfo { Name = "ResourceNavigationProperty", IsCollection = false };
+                navLink.Count = 10;
+
+                odataWriter.WriteStart(navLink);
+                odataWriter.WriteEnd();
+                odataWriter.WriteEnd();
+            };
+
+            Action testResponse = () => this.WriteAnnotationsAndValidatePayload(action, EntitySet, ODataFormat.Json, null, request: false, createFeedWriter: false);
+            testResponse.Throws<ODataException>(Strings.ODataWriterCore_QueryCountInODataNestedResourceInfo);
+        }
         #endregion Writing instance annotations on expanded feeds
 
         #region Write Delta Feed