diff --git a/src/backends/backendsCommon/test/OptimizedNetworkTests.cpp b/src/backends/backendsCommon/test/OptimizedNetworkTests.cpp
new file mode 100644
index 0000000..8d88241
--- /dev/null
+++ b/src/backends/backendsCommon/test/OptimizedNetworkTests.cpp
@@ -0,0 +1,330 @@
+//
+// Copyright © 2017 Arm Ltd. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+
+#include <armnn/ArmNN.hpp>
+
+#include <Graph.hpp>
+#include <Network.hpp>
+
+#include <reference/RefWorkloadFactory.hpp>
+
+#include <boost/test/unit_test.hpp>
+
+BOOST_AUTO_TEST_SUITE(OptimizedNetwork)
+
+BOOST_AUTO_TEST_CASE(SerializeToDot)
+{
+    armnn::Network net;
+
+    //Defines layers.
+    auto input = net.AddInputLayer(0);
+    auto add = net.AddAdditionLayer();
+    auto output = net.AddOutputLayer(0);
+
+    // Connects layers.
+    input->GetOutputSlot(0).Connect(add->GetInputSlot(0));
+    input->GetOutputSlot(0).Connect(add->GetInputSlot(1));
+    add->GetOutputSlot(0).Connect(output->GetInputSlot(0));
+
+    armnn::TensorShape shape({4});
+    armnn::TensorInfo info(shape, armnn::DataType::Float32);
+    input->GetOutputSlot(0).SetTensorInfo(info);
+    add->GetOutputSlot(0).SetTensorInfo(info);
+
+    armnn::IRuntime::CreationOptions options;
+    armnn::IRuntimePtr runtime(armnn::IRuntime::Create(options));
+
+    std::vector<armnn::BackendId> backends = {armnn::Compute::CpuRef};
+    armnn::IOptimizedNetworkPtr optimizedNet = armnn::Optimize(net, backends, runtime->GetDeviceSpec());
+
+    std::ostringstream ss;
+    optimizedNet->SerializeToDot(ss);
+
+    auto inputId = input->GetGuid();
+    auto addId = add->GetGuid();
+    auto outputId = output->GetGuid();
+
+    std::stringstream expected;
+    expected <<
+        "digraph Optimized {\n"
+        "    node [shape=\"record\"];\n"
+        "    edge [fontsize=8 fontcolor=\"blue\" fontname=\"arial-bold\"];\n"
+        "    " << inputId << " [label=\"{Input}\"];\n"
+        "    " << addId << " [label=\"{Addition}\"];\n"
+        "    " << outputId << " [label=\"{Output}\"];\n"
+        "    " << inputId << " -> " << addId << " [label=< [4] >];\n"
+        "    " << inputId << " -> " << addId << " [label=< [4] >];\n"
+        "    " << addId << " -> " << outputId << " [label=< [4] >];\n"
+        "}\n";
+
+    BOOST_TEST(ss.str() == expected.str());
+}
+
+BOOST_AUTO_TEST_CASE(OptimizeValidateDeviceNonSupportLayerNoFallback)
+{
+    // build up the structure of the network
+    armnn::INetworkPtr net(armnn::INetwork::Create());
+
+    armnn::IConnectableLayer* input = net->AddInputLayer(0);
+
+    // This layer configuration isn't supported by CpuAcc and isn't allowed to fall back, so Optimize will return null.
+    armnn::NormalizationDescriptor descriptor;
+    armnn::IConnectableLayer* normalize = net->AddNormalizationLayer(descriptor);
+
+    armnn::IConnectableLayer* output = net->AddOutputLayer(0);
+
+    input->GetOutputSlot(0).Connect(normalize->GetInputSlot(0));
+    normalize->GetOutputSlot(0).Connect(output->GetInputSlot(0));
+
+    input->GetOutputSlot(0).SetTensorInfo(armnn::TensorInfo({ 1, 1, 4, 4 }, armnn::DataType::Float32));
+    normalize->GetOutputSlot(0).SetTensorInfo(armnn::TensorInfo({ 1, 1, 4, 4 }, armnn::DataType::Float32));
+
+    armnn::IRuntime::CreationOptions options;
+    armnn::IRuntimePtr runtime(armnn::IRuntime::Create(options));
+
+    std::vector<armnn::BackendId> backends = { armnn::Compute::CpuAcc };
+    armnn::IOptimizedNetworkPtr optNet = armnn::Optimize(*net, backends, runtime->GetDeviceSpec());
+    BOOST_CHECK(!optNet);
+}
+
+BOOST_AUTO_TEST_CASE(OptimizeValidateDeviceNonSupportLayerWithFallback)
+{
+    // build up the structure of the network
+    armnn::INetworkPtr net(armnn::INetwork::Create());
+
+    armnn::IConnectableLayer* input = net->AddInputLayer(0);
+
+    // This layer configuration isn't supported by CpuAcc but it allows to fallback to CpuRef.
+    armnn::NormalizationDescriptor descriptor;
+    armnn::IConnectableLayer* normalize = net->AddNormalizationLayer(descriptor);
+
+    armnn::IConnectableLayer* output = net->AddOutputLayer(0);
+
+    input->GetOutputSlot(0).Connect(normalize->GetInputSlot(0));
+    normalize->GetOutputSlot(0).Connect(output->GetInputSlot(0));
+
+    input->GetOutputSlot(0).SetTensorInfo(armnn::TensorInfo({ 1, 1, 4, 4 }, armnn::DataType::Float32));
+    normalize->GetOutputSlot(0).SetTensorInfo(armnn::TensorInfo({ 1, 1, 4, 4 }, armnn::DataType::Float32));
+
+    armnn::IRuntime::CreationOptions options;
+    armnn::IRuntimePtr runtime(armnn::IRuntime::Create(options));
+
+    std::vector<armnn::BackendId> backends = { armnn::Compute::CpuAcc, armnn::Compute::CpuRef };
+    armnn::IOptimizedNetworkPtr optNet = armnn::Optimize(*net, backends, runtime->GetDeviceSpec());
+    BOOST_REQUIRE(optNet);
+
+    for (auto&& layer : static_cast<armnn::OptimizedNetwork*>(optNet.get())->GetGraph())
+    {
+        // If NEON is enabled, Input and Output layers are supported by CpuAcc,
+        // the other layers are supported by CpuRef.
+        // If NEON is not enabled, all layers are supported by CpuRef.
+#if ARMCOMPUTENEON_ENABLED
+        if (layer->GetType() == armnn::LayerType::Input || layer->GetType() == armnn::LayerType::Output)
+        {
+            BOOST_CHECK(layer->GetBackendId() == armnn::Compute::CpuAcc);
+        }
+        else if (layer->GetType() == armnn::LayerType::Normalization)
+        {
+            BOOST_CHECK(layer->GetBackendId() == armnn::Compute::CpuRef);
+        }
+#else
+        BOOST_CHECK(layer->GetBackendId() == armnn::Compute::CpuRef);
+#endif
+    }
+}
+
+BOOST_AUTO_TEST_CASE(OptimizeValidateWorkloadsUndefinedComputeDevice)
+{
+    const armnn::TensorInfo desc({3, 5}, armnn::DataType::Float32);
+
+    armnn::Network  net;
+
+    armnn::NormalizationDescriptor nmDesc;
+    armnn::ActivationDescriptor acDesc;
+
+    //    in
+    //     |
+    //    nm
+    //   /  |
+    //  ac  |
+    //   \  |
+    //    ml
+    //     |
+    //    sm
+    //     |
+    //    ot
+    armnn::IConnectableLayer* layer = net.AddInputLayer(0, "in");
+    layer->GetOutputSlot(0).SetTensorInfo(desc);
+
+    armnn::IConnectableLayer* const normLayer = net.AddNormalizationLayer(nmDesc, "nm");
+
+    layer->GetOutputSlot(0).Connect(normLayer->GetInputSlot(0));
+    normLayer->GetOutputSlot(0).SetTensorInfo(desc);
+
+    layer = net.AddActivationLayer(acDesc, "ac");
+
+    normLayer->GetOutputSlot(0).Connect(layer->GetInputSlot(0));
+    layer->GetOutputSlot(0).SetTensorInfo(desc);
+
+    armnn::IConnectableLayer* prevLayer = layer;
+    layer = net.AddMultiplicationLayer("ml");
+
+    prevLayer->GetOutputSlot(0).Connect(layer->GetInputSlot(0));
+    normLayer->GetOutputSlot(0).Connect(layer->GetInputSlot(1));
+    layer->GetOutputSlot(0).SetTensorInfo(desc);
+
+    prevLayer = layer;
+    armnn::SoftmaxDescriptor softmaxDescriptor;
+    layer = net.AddSoftmaxLayer(softmaxDescriptor, "sm");
+
+    prevLayer->GetOutputSlot(0).Connect(layer->GetInputSlot(0));
+    layer->GetOutputSlot(0).SetTensorInfo(desc);
+
+    prevLayer = layer;
+    layer = net.AddOutputLayer(0, "ot");
+
+    prevLayer->GetOutputSlot(0).Connect(layer->GetInputSlot(0));
+
+    armnn::IRuntime::CreationOptions options;
+    armnn::IRuntimePtr runtime(armnn::IRuntime::Create(options));
+
+    std::vector<armnn::BackendId> backends = { armnn::Compute::Undefined };
+
+    armnn::IOptimizedNetworkPtr optNet = armnn::Optimize(net, backends, runtime->GetDeviceSpec());
+    BOOST_CHECK(!optNet);
+
+}
+
+BOOST_AUTO_TEST_CASE(OptimizeValidateWorkloadsUndefinedComputeDeviceWithFallback)
+{
+    const armnn::TensorInfo desc({3, 5}, armnn::DataType::Float32);
+
+    armnn::Network  net;
+
+    armnn::NormalizationDescriptor nmDesc;
+    armnn::ActivationDescriptor acDesc;
+
+    //    in
+    //     |
+    //    nm
+    //   /  |
+    //  ac  |
+    //   \  |
+    //    ml
+    //     |
+    //    sm
+    //     |
+    //    ot
+    armnn::IConnectableLayer* layer = net.AddInputLayer(0, "in");
+    layer->GetOutputSlot(0).SetTensorInfo(desc);
+
+    armnn::IConnectableLayer* const normLayer = net.AddNormalizationLayer(nmDesc, "nm");
+
+    layer->GetOutputSlot(0).Connect(normLayer->GetInputSlot(0));
+    normLayer->GetOutputSlot(0).SetTensorInfo(desc);
+
+    layer = net.AddActivationLayer(acDesc, "ac");
+
+    normLayer->GetOutputSlot(0).Connect(layer->GetInputSlot(0));
+    layer->GetOutputSlot(0).SetTensorInfo(desc);
+
+    armnn::IConnectableLayer* prevLayer = layer;
+    layer = net.AddMultiplicationLayer("ml");
+
+    prevLayer->GetOutputSlot(0).Connect(layer->GetInputSlot(0));
+    normLayer->GetOutputSlot(0).Connect(layer->GetInputSlot(1));
+    layer->GetOutputSlot(0).SetTensorInfo(desc);
+
+    prevLayer = layer;
+    armnn::SoftmaxDescriptor softmaxDescriptor;
+    layer = net.AddSoftmaxLayer(softmaxDescriptor, "sm");
+
+    prevLayer->GetOutputSlot(0).Connect(layer->GetInputSlot(0));
+    layer->GetOutputSlot(0).SetTensorInfo(desc);
+
+    prevLayer = layer;
+    layer = net.AddOutputLayer(0, "ot");
+
+    prevLayer->GetOutputSlot(0).Connect(layer->GetInputSlot(0));
+
+    armnn::IRuntime::CreationOptions options;
+    armnn::IRuntimePtr runtime(armnn::IRuntime::Create(options));
+
+    std::vector<armnn::BackendId> backends = { armnn::Compute::Undefined, armnn::Compute::CpuRef };
+
+    armnn::IOptimizedNetworkPtr optNet = armnn::Optimize(net, backends, runtime->GetDeviceSpec());
+    BOOST_CHECK(optNet);
+
+    // validate workloads
+    armnn::RefWorkloadFactory fact;
+    for (auto&& layer : static_cast<armnn::OptimizedNetwork*>(optNet.get())->GetGraph())
+    {
+        BOOST_CHECK(layer->GetBackendId() == armnn::Compute::CpuRef);
+        BOOST_CHECK_NO_THROW(
+            layer->CreateWorkload(static_cast<armnn::OptimizedNetwork*>(optNet.get())->GetGraph(), fact));
+    }
+}
+
+BOOST_AUTO_TEST_CASE(OptimizeValidateWorkloadsDuplicateComputeDeviceWithFallback)
+{
+    // build up the structure of the network
+    armnn::INetworkPtr net(armnn::INetwork::Create());
+
+    armnn::IConnectableLayer* input = net->AddInputLayer(0);
+
+    // This layer configuration isn't supported by CpuAcc but it allows to fallback to CpuRef.
+    armnn::NormalizationDescriptor descriptor;
+    armnn::IConnectableLayer* normalize = net->AddNormalizationLayer(descriptor);
+
+    armnn::IConnectableLayer* output = net->AddOutputLayer(0);
+
+    input->GetOutputSlot(0).Connect(normalize->GetInputSlot(0));
+    normalize->GetOutputSlot(0).Connect(output->GetInputSlot(0));
+
+    input->GetOutputSlot(0).SetTensorInfo(armnn::TensorInfo({ 1, 1, 4, 4 }, armnn::DataType::Float32));
+    normalize->GetOutputSlot(0).SetTensorInfo(armnn::TensorInfo({ 1, 1, 4, 4 }, armnn::DataType::Float32));
+
+    armnn::IRuntime::CreationOptions options;
+    armnn::IRuntimePtr runtime(armnn::IRuntime::Create(options));
+
+    std::vector<armnn::BackendId> backends = { armnn::Compute::CpuAcc,
+                                             armnn::Compute::GpuAcc,
+                                             armnn::Compute::CpuRef };
+
+    armnn::IOptimizedNetworkPtr optNet = armnn::Optimize(*net, backends, runtime->GetDeviceSpec());
+    BOOST_REQUIRE(optNet);
+
+    for (auto&& layer : static_cast<armnn::OptimizedNetwork*>(optNet.get())->GetGraph())
+    {
+        // If NEON is enabled, Input and Output layers are supported by CpuAcc,
+        // the other layers are supported by CpuRef.
+        // If only CL is enabled, Input and Output layers are supported by GpuAcc,
+        // the other layers are supported by CpuRef.
+        // If neither NEON, nor CL is enabled, all layers are supported by CpuRef.
+#if ARMCOMPUTENEON_ENABLED
+        if (layer->GetType() == armnn::LayerType::Input || layer->GetType() == armnn::LayerType::Output)
+        {
+            BOOST_CHECK(layer->GetBackendId() == armnn::Compute::CpuAcc);
+        }
+        else if (layer->GetType() == armnn::LayerType::Normalization)
+        {
+            BOOST_CHECK(layer->GetBackendId() == armnn::Compute::CpuRef);
+        }
+#elif ARMCOMPUTECL_ENABLED
+        if (layer->GetType() == armnn::LayerType::Input || layer->GetType() == armnn::LayerType::Output)
+        {
+            BOOST_CHECK(layer->GetBackendId() == armnn::Compute::GpuAcc);
+        }
+        else if (layer->GetType() == armnn::LayerType::Normalization)
+        {
+            BOOST_CHECK(layer->GetBackendId() == armnn::Compute::CpuRef);
+        }
+#else
+        BOOST_CHECK(layer->GetBackendId() == armnn::Compute::CpuRef);
+#endif
+    }
+}
+
+BOOST_AUTO_TEST_SUITE_END()