diff --git a/Apps/UnitTests/CMakeLists.txt b/Apps/UnitTests/CMakeLists.txt
index ae1fb713e..e99b63e43 100644
--- a/Apps/UnitTests/CMakeLists.txt
+++ b/Apps/UnitTests/CMakeLists.txt
@@ -24,6 +24,11 @@ set(SOURCES
     "Source/Utils.h"
     "Source/Utils.${GRAPHICS_API}.${BABYLON_NATIVE_PLATFORM_IMPL_EXT}")
 
+if(GRAPHICS_API STREQUAL "D3D11" OR GRAPHICS_API STREQUAL "D3D12")
+    set(SOURCES ${SOURCES}
+        "Source/Tests.Device.cpp")
+endif()
+
 if(GRAPHICS_API STREQUAL "D3D11")
     set(SOURCES ${SOURCES}
         "Source/Tests.Device.${GRAPHICS_API}.cpp"
diff --git a/Apps/UnitTests/Source/Tests.Device.cpp b/Apps/UnitTests/Source/Tests.Device.cpp
new file mode 100644
index 000000000..ab24ef4af
--- /dev/null
+++ b/Apps/UnitTests/Source/Tests.Device.cpp
@@ -0,0 +1,52 @@
+#include <gtest/gtest.h>
+
+#include <Babylon/Graphics/Device.h>
+
+#include "Utils.h"
+
+extern Babylon::Graphics::Configuration g_deviceConfig;
+
+// Verifies UpdateDevice replaces the active graphics device after a DisableRendering / EnableRendering cycle.
+TEST(Device, UpdateDevice)
+{
+    Babylon::Graphics::DeviceT deviceA = CreateTestGraphicsDevice();
+    ASSERT_NE(deviceA, nullptr);
+
+    Babylon::Graphics::DeviceT deviceB = nullptr;
+
+    {
+        // Inherit Window / Width / Height from the App layer's config so bgfx can manage its own
+        // swap chain on the HWND. We deliberately do NOT set BackBufferColor here -- the
+        // caller-provided-BackBuffer flow is a separate concern covered by TEST(Device, BackBuffer).
+        Babylon::Graphics::Configuration config = g_deviceConfig;
+        config.Device = deviceA;
+
+        Babylon::Graphics::Device device{config};
+
+        // Drive a frame to force EnableRendering -> bgfx::init with deviceA.
+        device.StartRenderingCurrentFrame();
+        device.FinishRenderingCurrentFrame();
+
+        EXPECT_EQ(device.GetPlatformInfo().Device, deviceA);
+
+        deviceB = CreateTestGraphicsDevice();
+        ASSERT_NE(deviceB, nullptr);
+
+        // Tear bgfx down before pointing the device at the new graphics device.
+        device.DisableRendering();
+
+        device.UpdateDevice(deviceB);
+
+        // Drive another frame to force EnableRendering -> bgfx::init with deviceB.
+        device.StartRenderingCurrentFrame();
+        device.FinishRenderingCurrentFrame();
+
+        EXPECT_EQ(device.GetPlatformInfo().Device, deviceB);
+        // Note: no EXPECT_NE(deviceB, deviceA). On D3D12 with WARP, D3D12CreateDevice returns the
+        // same singleton pointer on successive calls so distinctness is not assertable. On D3D11
+        // distinctness holds but exercising it does not add value over the EXPECT_EQ above.
+    }   // Babylon::Graphics::Device destructs here, calling DisableRendering on deviceB.
+
+    DestroyTestGraphicsDevice(deviceB);
+    DestroyTestGraphicsDevice(deviceA);
+}
diff --git a/Apps/UnitTests/Source/Utils.D3D11.cpp b/Apps/UnitTests/Source/Utils.D3D11.cpp
index e5bfd2c26..8e57368c8 100644
--- a/Apps/UnitTests/Source/Utils.D3D11.cpp
+++ b/Apps/UnitTests/Source/Utils.D3D11.cpp
@@ -26,3 +26,28 @@ void DestroyTestTexture(Babylon::Graphics::TextureT texture)
 {
     texture->Release();
 }
+
+Babylon::Graphics::DeviceT CreateTestGraphicsDevice()
+{
+    ID3D11Device* device = nullptr;
+    EXPECT_HRESULT_SUCCEEDED(D3D11CreateDevice(
+        nullptr,
+        D3D_DRIVER_TYPE_WARP,
+        nullptr,
+        0,
+        nullptr,
+        0,
+        D3D11_SDK_VERSION,
+        &device,
+        nullptr,
+        nullptr));
+    return device;
+}
+
+void DestroyTestGraphicsDevice(Babylon::Graphics::DeviceT device)
+{
+    if (device != nullptr)
+    {
+        device->Release();
+    }
+}
diff --git a/Apps/UnitTests/Source/Utils.D3D12.cpp b/Apps/UnitTests/Source/Utils.D3D12.cpp
index 65b4f6d23..06197ad60 100644
--- a/Apps/UnitTests/Source/Utils.D3D12.cpp
+++ b/Apps/UnitTests/Source/Utils.D3D12.cpp
@@ -1,6 +1,9 @@
 #include <gtest/gtest.h>
 #include "Utils.h"
 
+#include <dxgi1_4.h>
+#include <winrt/base.h>
+
 Babylon::Graphics::TextureT CreateTestTexture(Babylon::Graphics::DeviceT device, uint32_t width, uint32_t height, uint32_t arraySize)
 {
     D3D12_RESOURCE_DESC desc{};
@@ -39,3 +42,25 @@ void DestroyTestTexture(Babylon::Graphics::TextureT texture)
 {
     texture->Release();
 }
+
+Babylon::Graphics::DeviceT CreateTestGraphicsDevice()
+{
+    winrt::com_ptr<IDXGIFactory4> factory;
+    winrt::check_hresult(CreateDXGIFactory1(IID_PPV_ARGS(factory.put())));
+
+    winrt::com_ptr<IDXGIAdapter> warpAdapter;
+    winrt::check_hresult(factory->EnumWarpAdapter(IID_PPV_ARGS(warpAdapter.put())));
+
+    ID3D12Device* device = nullptr;
+    winrt::check_hresult(D3D12CreateDevice(warpAdapter.get(), D3D_FEATURE_LEVEL_11_0, IID_PPV_ARGS(&device)));
+
+    return device;
+}
+
+void DestroyTestGraphicsDevice(Babylon::Graphics::DeviceT device)
+{
+    if (device != nullptr)
+    {
+        device->Release();
+    }
+}
diff --git a/Apps/UnitTests/Source/Utils.h b/Apps/UnitTests/Source/Utils.h
index a3ee6a982..60e7a76fd 100644
--- a/Apps/UnitTests/Source/Utils.h
+++ b/Apps/UnitTests/Source/Utils.h
@@ -4,3 +4,17 @@
 
 Babylon::Graphics::TextureT CreateTestTexture(Babylon::Graphics::DeviceT device, uint32_t width, uint32_t height, uint32_t arraySize = 1);
 void DestroyTestTexture(Babylon::Graphics::TextureT texture);
+
+// Returns a graphics device suitable for use as Babylon::Graphics::Configuration::Device. The
+// returned handle is owned by the caller and must be released with DestroyTestGraphicsDevice.
+//
+// Defined only on D3D11 and D3D12 -- the Tests.Device.cpp test that consumes these helpers is
+// gated to those backends. On D3D11 returns an ID3D11Device created via D3D11CreateDevice(WARP);
+// on D3D12 returns an ID3D12Device created via D3D12CreateDevice on the WARP DXGI adapter.
+//
+// Note: on D3D12, D3D12CreateDevice(WARP) returns the same singleton pointer on successive calls
+// in the same process, so two calls in a row may return equal handles. D3D11CreateDevice(WARP)
+// does return distinct handles per call.
+Babylon::Graphics::DeviceT CreateTestGraphicsDevice();
+
+void DestroyTestGraphicsDevice(Babylon::Graphics::DeviceT device);