Deleted Serialize_ClientInfo_WithNull Unit Test in JasonHelperTests (#5527)

Author: Robbie-Microsoft

tests/Microsoft.Identity.Test.Unit/UtilTests/JsonHelperTests.cs

@@ -70,20 +70,6 @@ public void Serialize_ClientInfo()
             JsonTestUtils.AssertJsonDeepEquals(expectedJson, actualJson);
         }
 
-        [TestMethod]
-        public void Serialize_ClientInfo_WithNull()
-        {
-            ClientInfo clientInfo = new ClientInfo() { UniqueObjectIdentifier = "some_uid" };
-
-            string actualJson = JsonHelper.SerializeToJson(clientInfo);
-            string expectedJson = @"{
-                                       ""uid"": ""some_uid"",
-                                       ""utid"": null
-                                    }";
-
-            JsonTestUtils.AssertJsonDeepEquals(expectedJson, actualJson);
-        }
-
         [TestMethod]
         public void Serialize_OldDictionaryTokenCache()
         {