diff --git a/src/Microsoft.Health.Dicom.Core.UnitTests/Features/Diagnostic/LogForwarderExtensionsTests.cs b/src/Microsoft.Health.Dicom.Core.UnitTests/Features/Diagnostic/LogForwarderExtensionsTests.cs
new file mode 100644
index 0000000000..b3a8c8bb29
--- /dev/null
+++ b/src/Microsoft.Health.Dicom.Core.UnitTests/Features/Diagnostic/LogForwarderExtensionsTests.cs
@@ -0,0 +1,119 @@
+// -------------------------------------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License (MIT). See LICENSE in the repo root for license information.
+// -------------------------------------------------------------------------------------------------
+
+using System;
+using Microsoft.ApplicationInsights;
+using Microsoft.ApplicationInsights.Extensibility;
+using Microsoft.Health.Dicom.Core.Features.Diagnostic;
+using Microsoft.Health.Dicom.Core.Features.Model;
+using Microsoft.Health.Dicom.Core.Features.Partitioning;
+using Microsoft.Health.Dicom.Tests.Common;
+using Xunit;
+
+namespace Microsoft.Health.Dicom.Core.UnitTests.Features.Diagnostic;
+
+public class LogForwarderExtensionsTests
+{
+    [Fact]
+    public void GivenClientUsingForwardTelemetry_ExpectForwardLogFlagIsSetWithNoAdditionalProperties()
+    {
+        (TelemetryClient telemetryClient, var channel) = CreateTelemetryClientWithChannel();
+        telemetryClient.ForwardLogTrace("A message");
+
+        Assert.Single(channel.Items);
+#pragma warning disable CS0618 // Type or member is obsolete
+        Assert.Single(channel.Items[0].Context.Properties);
+        Assert.Equal(Boolean.TrueString, channel.Items[0].Context.Properties["forwardLog"]);
+#pragma warning restore CS0618 // Type or member is obsolete
+    }
+
+    [Fact]
+    public void GivenClientUsingForwardTelemetryWithIdentifier_ExpectForwardLogFlagIsSetWithAdditionalProperties()
+    {
+        (TelemetryClient telemetryClient, var channel) = CreateTelemetryClientWithChannel();
+
+        var expectedIdentifier = new InstanceIdentifier(TestUidGenerator.Generate(), TestUidGenerator.Generate(),
+            TestUidGenerator.Generate(), Partition.Default);
+        telemetryClient.ForwardLogTrace("A message", expectedIdentifier);
+
+        Assert.Single(channel.Items);
+#pragma warning disable CS0618 // Type or member is obsolete
+        Assert.Equal(5, channel.Items[0].Context.Properties.Count);
+        Assert.Equal(expectedIdentifier.SopInstanceUid,
+            channel.Items[0].Context.Properties["dicomAdditionalInformation_sopInstanceUID"]);
+        Assert.Equal(expectedIdentifier.SeriesInstanceUid,
+            channel.Items[0].Context.Properties["dicomAdditionalInformation_seriesInstanceUID"]);
+        Assert.Equal(expectedIdentifier.StudyInstanceUid,
+            channel.Items[0].Context.Properties["dicomAdditionalInformation_studyInstanceUID"]);
+        Assert.Equal(expectedIdentifier.Partition.Name,
+            channel.Items[0].Context.Properties["dicomAdditionalInformation_partitionName"]);
+        Assert.Equal(Boolean.TrueString, channel.Items[0].Context.Properties["forwardLog"]);
+#pragma warning restore CS0618 // Type or member is obsolete
+    }
+
+    [Fact]
+    public void GivenClientUsingForwardTelemetry_whenForwardOperationLogTraceWithSizeLimit_ExpectForwardLogFlagIsSet()
+    {
+        (TelemetryClient telemetryClient, var channel) = CreateTelemetryClientWithChannel();
+
+        var operationId = Guid.NewGuid().ToString();
+        var input = "input";
+        var message = "a message";
+        telemetryClient.ForwardOperationLogTrace(message, operationId, input);
+
+        Assert.Single(channel.Items);
+#pragma warning disable CS0618 // Type or member is obsolete
+        Assert.Equal(3, channel.Items[0].Context.Properties.Count);
+        Assert.Equal(Boolean.TrueString, channel.Items[0].Context.Properties["forwardLog"]);
+        Assert.Equal(operationId, channel.Items[0].Context.Properties["dicomAdditionalInformation_operationId"]);
+        Assert.Equal(input, channel.Items[0].Context.Properties["dicomAdditionalInformation_input"]);
+#pragma warning restore CS0618 // Type or member is obsolete
+    }
+
+    [Fact]
+    public void GivenClientUsingForwardTelemetry_whenForwardOperationLogTraceWithSizeLimitExceeded_ExpectForwardLogFlagIsSetAndMultipleTelemetriesEmitted()
+    {
+        (TelemetryClient telemetryClient, var channel) = CreateTelemetryClientWithChannel();
+
+        var operationId = Guid.NewGuid().ToString();
+        var expectedFirstItemInput = "a".PadRight(32 * 1024); // split occurs at 32 kb
+        var expectedSecondItemInput = "b".PadRight(32 * 1024); // split occurs at 32 kb
+        var fullInput = expectedFirstItemInput + expectedSecondItemInput;
+        var message = "a message";
+        telemetryClient.ForwardOperationLogTrace(message, operationId, fullInput);
+
+        Assert.Equal(2, channel.Items.Count);
+
+#pragma warning disable CS0618 // Type or member is obsolete
+        var firstItem = channel.Items[0];
+        Assert.Equal(3, firstItem.Context.Properties.Count);
+        Assert.Equal(Boolean.TrueString, firstItem.Context.Properties["forwardLog"]);
+        Assert.Equal(operationId, firstItem.Context.Properties["dicomAdditionalInformation_operationId"]);
+        Assert.Equal(expectedFirstItemInput, firstItem.Context.Properties["dicomAdditionalInformation_input"]);
+
+        var secondItem = channel.Items[1];
+        Assert.Equal(3, secondItem.Context.Properties.Count);
+        Assert.Equal(Boolean.TrueString, secondItem.Context.Properties["forwardLog"]);
+        Assert.Equal(operationId, secondItem.Context.Properties["dicomAdditionalInformation_operationId"]);
+        Assert.Equal(expectedSecondItemInput, secondItem.Context.Properties["dicomAdditionalInformation_input"]);
+#pragma warning restore CS0618 // Type or member is obsolete
+    }
+
+    private static (TelemetryClient, MockTelemetryChannel) CreateTelemetryClientWithChannel()
+    {
+        MockTelemetryChannel channel = new MockTelemetryChannel();
+
+        TelemetryConfiguration configuration = new TelemetryConfiguration
+        {
+            TelemetryChannel = channel,
+#pragma warning disable CS0618 // Type or member is obsolete
+            InstrumentationKey = Guid.NewGuid().ToString()
+#pragma warning restore CS0618 // Type or member is obsolete
+        };
+        configuration.TelemetryInitializers.Add(new OperationCorrelationTelemetryInitializer());
+
+        return (new TelemetryClient(configuration), channel);
+    }
+}
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diff --git a/src/Microsoft.Health.Dicom.Core.UnitTests/Features/Diagnostic/MockTelemetryChannel.cs b/src/Microsoft.Health.Dicom.Core.UnitTests/Features/Diagnostic/MockTelemetryChannel.cs
new file mode 100644
index 0000000000..01f239a027
--- /dev/null
+++ b/src/Microsoft.Health.Dicom.Core.UnitTests/Features/Diagnostic/MockTelemetryChannel.cs
@@ -0,0 +1,33 @@
+// -------------------------------------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License (MIT). See LICENSE in the repo root for license information.
+// -------------------------------------------------------------------------------------------------
+
+using System;
+using System.Collections.Generic;
+using Microsoft.ApplicationInsights.Channel;
+
+namespace Microsoft.Health.Dicom.Core.UnitTests.Features.Diagnostic;
+
+internal class MockTelemetryChannel : ITelemetryChannel
+{
+    public IList<ITelemetry> Items { get; private set; } = new List<ITelemetry>();
+
+    public void Send(ITelemetry item)
+    {
+        Items.Add(item);
+    }
+
+    public void Flush()
+    {
+        throw new NotImplementedException();
+    }
+
+    public bool? DeveloperMode { get; set; }
+    public string EndpointAddress { get; set; }
+
+    public void Dispose()
+    {
+        throw new NotImplementedException();
+    }
+}
\ No newline at end of file