diff --git a/Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.EmulatorTests/FeedToken/ChangeFeedIteratorCoreTests.cs b/Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.EmulatorTests/FeedToken/ChangeFeedIteratorCoreTests.cs
index 37892a4481..ebaa41dffb 100644
--- a/Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.EmulatorTests/FeedToken/ChangeFeedIteratorCoreTests.cs
+++ b/Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.EmulatorTests/FeedToken/ChangeFeedIteratorCoreTests.cs
@@ -148,7 +148,7 @@ await feedIterator.ReadNextAsync(this.cancellationToken))
         /// </summary>
         /// <returns></returns>
         [TestMethod]
-        //[Timeout(30000)]
+        [Timeout(30000)]
         public async Task ChangeFeedIteratorCore_PartitionKey_ReadAll()
         {
             int totalCount = 0;
diff --git a/Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.Tests/ChangeFeed/ChangeFeedStateCosmosElementSerializerTests.cs b/Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.Tests/ChangeFeed/ChangeFeedStateCosmosElementSerializerTests.cs
new file mode 100644
index 0000000000..6a36424169
--- /dev/null
+++ b/Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.Tests/ChangeFeed/ChangeFeedStateCosmosElementSerializerTests.cs
@@ -0,0 +1,70 @@
+//------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//------------------------------------------------------------
+
+namespace Microsoft.Azure.Cosmos.Tests.ChangeFeed
+{
+    using System;
+    using Microsoft.Azure.Cosmos.ChangeFeed.Pagination;
+    using Microsoft.Azure.Cosmos.CosmosElements;
+    using Microsoft.Azure.Cosmos.Query.Core.Monads;
+    using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+    [TestClass]
+    public sealed class ChangeFeedStateCosmosElementSerializerTests
+    {
+        [TestMethod]
+        public void Now()
+        {
+            ChangeFeedState now = ChangeFeedState.Now();
+            CosmosElement cosmosElement = ChangeFeedStateCosmosElementSerializer.ToCosmosElement(now);
+            TryCatch<ChangeFeedState> monadicState = ChangeFeedStateCosmosElementSerializer.MonadicFromCosmosElement(cosmosElement);
+            Assert.IsTrue(monadicState.Succeeded);
+            Assert.IsTrue(monadicState.Result is ChangeFeedStateNow);
+        }
+
+        [TestMethod]
+        public void Beginning()
+        {
+            ChangeFeedState beginning = ChangeFeedState.Beginning();
+            CosmosElement cosmosElement = ChangeFeedStateCosmosElementSerializer.ToCosmosElement(beginning);
+            TryCatch<ChangeFeedState> monadicState = ChangeFeedStateCosmosElementSerializer.MonadicFromCosmosElement(cosmosElement);
+            Assert.IsTrue(monadicState.Succeeded);
+            Assert.IsTrue(monadicState.Result is ChangeFeedStateBeginning);
+        }
+
+        [TestMethod]
+        public void Time()
+        {
+            DateTime startTime = DateTime.MinValue.ToUniversalTime();
+            ChangeFeedState time = ChangeFeedState.Time(startTime);
+            CosmosElement cosmosElement = ChangeFeedStateCosmosElementSerializer.ToCosmosElement(time);
+            TryCatch<ChangeFeedState> monadicState = ChangeFeedStateCosmosElementSerializer.MonadicFromCosmosElement(cosmosElement);
+            Assert.IsTrue(monadicState.Succeeded);
+            if (!(monadicState.Result is ChangeFeedStateTime stateTime))
+            {
+                Assert.Fail();
+                return;
+            }
+
+            Assert.AreEqual(stateTime.StartTime, startTime);
+        }
+
+        [TestMethod]
+        public void Continuation()
+        {
+            CosmosString continuation = CosmosString.Create("asdf");
+            ChangeFeedState time = ChangeFeedState.Continuation(continuation);
+            CosmosElement cosmosElement = ChangeFeedStateCosmosElementSerializer.ToCosmosElement(time);
+            TryCatch<ChangeFeedState> monadicState = ChangeFeedStateCosmosElementSerializer.MonadicFromCosmosElement(cosmosElement);
+            Assert.IsTrue(monadicState.Succeeded);
+            if (!(monadicState.Result is ChangeFeedStateContinuation changeFeedContinuation))
+            {
+                Assert.Fail();
+                return;
+            }
+
+            Assert.AreEqual(changeFeedContinuation.ContinuationToken, continuation);
+        }
+    }
+}
diff --git a/Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.Tests/FeedRange/FeedRangeCosmosElementSerializerTests.cs b/Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.Tests/FeedRange/FeedRangeCosmosElementSerializerTests.cs
new file mode 100644
index 0000000000..bfcfed19d7
--- /dev/null
+++ b/Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.Tests/FeedRange/FeedRangeCosmosElementSerializerTests.cs
@@ -0,0 +1,51 @@
+//------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//------------------------------------------------------------
+ 
+namespace Microsoft.Azure.Cosmos.Tests.FeedRange
+{
+    using Microsoft.Azure.Cosmos.CosmosElements;
+    using Microsoft.Azure.Cosmos.Query.Core.Monads;
+    using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+    [TestClass]
+    public sealed class FeedRangeCosmosElementSerializerTests
+    {
+        [TestMethod]
+        public void LogicalPartitionKey()
+        {
+            Cosmos.PartitionKey somePartitionKey = new Cosmos.PartitionKey(42);
+            FeedRangeInternal feedRange = new FeedRangePartitionKey(somePartitionKey);
+            AssertRoundTrip(feedRange);
+        }
+
+        [TestMethod]
+        public void PhysicalPartitionKeyRangeId()
+        {
+            int physicalPkRangeId = 0;
+            FeedRangeInternal feedRange = new FeedRangePartitionKeyRange(physicalPkRangeId.ToString());
+            AssertRoundTrip(feedRange);
+        }
+
+        [TestMethod]
+        public void EffectivePartitionKeyRange()
+        {
+            Microsoft.Azure.Documents.Routing.Range<string> range = new Microsoft.Azure.Documents.Routing.Range<string>(
+                min: "A", 
+                max: "B", 
+                isMinInclusive: true, 
+                isMaxInclusive: false);
+
+            FeedRangeInternal feedRange = new FeedRangeEpk(range);
+            AssertRoundTrip(feedRange);
+        }
+
+        private static void AssertRoundTrip(FeedRangeInternal feedRange)
+        {
+            CosmosElement cosmosElement = FeedRangeCosmosElementSerializer.ToCosmosElement(feedRange);
+            TryCatch<FeedRangeInternal> monad = FeedRangeCosmosElementSerializer.MonadicCreateFromCosmosElement(cosmosElement);
+            Assert.IsTrue(monad.Succeeded);
+            Assert.AreEqual(feedRange.ToJsonString(), monad.Result.ToJsonString());
+        }
+    }
+}