diff --git a/shell/platform/tizen/BUILD.gn b/shell/platform/tizen/BUILD.gn
index ea2fbf946f90e..d6001c839ee4d 100644
--- a/shell/platform/tizen/BUILD.gn
+++ b/shell/platform/tizen/BUILD.gn
@@ -245,6 +245,8 @@ template("embedder_executable") {
       "channels/localization_channel_stub.cc",
       "channels/platform_channel_stub.cc",
       "channels/settings_channel_stub.cc",
+      "external_texture_pixel_gl_stub.cc",
+      "external_texture_surface_gl_stub.cc",
       "tizen_log_stub.cc",
       "tizen_renderer_evas_gl.cc",
     ]
@@ -303,6 +305,7 @@ embedder_executable("flutter_tizen_unittests") {
 
   sources = [
     "flutter_tizen_engine_unittest.cc",
+    "flutter_tizen_texture_registrar_unittests.cc",
     "testing/mock_engine.cc",
   ]
 
diff --git a/shell/platform/tizen/external_texture_pixel_gl.cc b/shell/platform/tizen/external_texture_pixel_gl.cc
index 846bdb0737422..085a2f19e408d 100644
--- a/shell/platform/tizen/external_texture_pixel_gl.cc
+++ b/shell/platform/tizen/external_texture_pixel_gl.cc
@@ -45,6 +45,10 @@ ExternalTexturePixelGL::ExternalTexturePixelGL(
       user_data_(user_data) {}
 
 bool ExternalTexturePixelGL::CopyPixelBuffer(size_t& width, size_t& height) {
+  if (!texture_callback_) {
+    return false;
+  }
+
   const FlutterDesktopPixelBuffer* pixel_buffer =
       texture_callback_(width, height, user_data_);
 
diff --git a/shell/platform/tizen/external_texture_pixel_gl_stub.cc b/shell/platform/tizen/external_texture_pixel_gl_stub.cc
new file mode 100644
index 0000000000000..f6a1ae0a1a5cc
--- /dev/null
+++ b/shell/platform/tizen/external_texture_pixel_gl_stub.cc
@@ -0,0 +1,29 @@
+// Copyright 2021 Samsung Electronics Co., Ltd. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "flutter/shell/platform/tizen/external_texture_pixel_gl.h"
+
+namespace flutter {
+
+ExternalTexturePixelGL::ExternalTexturePixelGL(
+    FlutterDesktopPixelBufferTextureCallback texture_callback,
+    void* user_data)
+    : ExternalTexture(),
+      texture_callback_(texture_callback),
+      user_data_(user_data) {}
+
+bool ExternalTexturePixelGL::PopulateTexture(
+    size_t width,
+    size_t height,
+    FlutterOpenGLTexture* opengl_texture) {
+  return CopyPixelBuffer(width, height);
+}
+
+bool ExternalTexturePixelGL::CopyPixelBuffer(size_t& width, size_t& height) {
+  if (texture_callback_ && user_data_) {
+    return true;
+  }
+  return false;
+}
+}  // namespace flutter
diff --git a/shell/platform/tizen/external_texture_surface_gl.cc b/shell/platform/tizen/external_texture_surface_gl.cc
index cba8bdf277eac..b748c40c66221 100644
--- a/shell/platform/tizen/external_texture_surface_gl.cc
+++ b/shell/platform/tizen/external_texture_surface_gl.cc
@@ -54,6 +54,9 @@ bool ExternalTextureSurfaceGL::PopulateTexture(
     size_t width,
     size_t height,
     FlutterOpenGLTexture* opengl_texture) {
+  if (!texture_callback_) {
+    return false;
+  }
   const FlutterDesktopGpuBuffer* gpu_buffer =
       texture_callback_(width, height, user_data_);
   if (!gpu_buffer) {
@@ -153,7 +156,9 @@ bool ExternalTextureSurfaceGL::PopulateTexture(
 }
 
 void ExternalTextureSurfaceGL::OnDestruction() {
-  destruction_callback_(user_data_);
+  if (destruction_callback_) {
+    destruction_callback_(user_data_);
+  }
 }
 
 }  // namespace flutter
diff --git a/shell/platform/tizen/external_texture_surface_gl_stub.cc b/shell/platform/tizen/external_texture_surface_gl_stub.cc
new file mode 100644
index 0000000000000..07f21e8673ae6
--- /dev/null
+++ b/shell/platform/tizen/external_texture_surface_gl_stub.cc
@@ -0,0 +1,38 @@
+// Copyright 2021 Samsung Electronics Co., Ltd. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "external_texture_surface_gl.h"
+
+namespace flutter {
+
+ExternalTextureSurfaceGL::ExternalTextureSurfaceGL(
+    FlutterDesktopGpuBufferTextureCallback texture_callback,
+    FlutterDesktopGpuBufferDestructionCallback destruction_callback,
+    void* user_data)
+    : ExternalTexture(),
+      texture_callback_(texture_callback),
+      destruction_callback_(destruction_callback),
+      user_data_(user_data) {}
+
+ExternalTextureSurfaceGL::~ExternalTextureSurfaceGL() {
+  state_.release();
+}
+
+bool ExternalTextureSurfaceGL::PopulateTexture(
+    size_t width,
+    size_t height,
+    FlutterOpenGLTexture* opengl_texture) {
+  if (texture_callback_ && destruction_callback_ && user_data_) {
+    return true;
+  }
+  return false;
+}
+
+void ExternalTextureSurfaceGL::OnDestruction() {
+  if (destruction_callback_) {
+    destruction_callback_(user_data_);
+  }
+}
+
+}  // namespace flutter
diff --git a/shell/platform/tizen/flutter_tizen_engine.h b/shell/platform/tizen/flutter_tizen_engine.h
index fad50e4278b65..163f2a99d20f5 100644
--- a/shell/platform/tizen/flutter_tizen_engine.h
+++ b/shell/platform/tizen/flutter_tizen_engine.h
@@ -142,6 +142,8 @@ class FlutterTizenEngine : public TizenRenderer::Delegate {
   std::unique_ptr<PlatformViewChannel> platform_view_channel;
 
  private:
+  friend class EngineModifier;
+
   // Whether the engine is running in headed or headless mode.
   bool IsHeaded() { return renderer != nullptr; }
 
diff --git a/shell/platform/tizen/flutter_tizen_texture_registrar.cc b/shell/platform/tizen/flutter_tizen_texture_registrar.cc
index e84cd4d68a49d..817ff5401f2ae 100644
--- a/shell/platform/tizen/flutter_tizen_texture_registrar.cc
+++ b/shell/platform/tizen/flutter_tizen_texture_registrar.cc
@@ -7,10 +7,8 @@
 #include <iostream>
 #include <mutex>
 
-#ifndef __X64_SHELL__
 #include "flutter/shell/platform/tizen/external_texture_pixel_gl.h"
 #include "flutter/shell/platform/tizen/external_texture_surface_gl.h"
-#endif
 #include "flutter/shell/platform/tizen/flutter_tizen_engine.h"
 #include "flutter/shell/platform/tizen/tizen_log.h"
 
@@ -90,10 +88,6 @@ bool FlutterTizenTextureRegistrar::PopulateTexture(
 std::unique_ptr<ExternalTexture>
 FlutterTizenTextureRegistrar::CreateExternalTexture(
     const FlutterDesktopTextureInfo* texture_info) {
-#ifdef __X64_SHELL__
-  FT_UNIMPLEMENTED();
-  return nullptr;
-#else
   switch (texture_info->type) {
     case kFlutterDesktopPixelBufferTexture:
       return std::make_unique<ExternalTexturePixelGL>(
@@ -110,7 +104,6 @@ FlutterTizenTextureRegistrar::CreateExternalTexture(
       FT_LOGE("Invalid texture type.");
       return nullptr;
   }
-#endif
 }
 
 }  // namespace flutter
diff --git a/shell/platform/tizen/flutter_tizen_texture_registrar_unittests.cc b/shell/platform/tizen/flutter_tizen_texture_registrar_unittests.cc
new file mode 100644
index 0000000000000..1ec19707c5433
--- /dev/null
+++ b/shell/platform/tizen/flutter_tizen_texture_registrar_unittests.cc
@@ -0,0 +1,126 @@
+// Copyright 2021 Samsung Electronics Co., Ltd. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <iostream>
+
+#include "flutter/shell/platform/embedder/test_utils/proc_table_replacement.h"
+#include "flutter/shell/platform/tizen/flutter_tizen_engine.h"
+#include "flutter/shell/platform/tizen/flutter_tizen_texture_registrar.h"
+#include "flutter/shell/platform/tizen/testing/engine_modifier.h"
+#include "gtest/gtest.h"
+
+namespace flutter {
+namespace testing {
+
+class FlutterTizenTextureRegistrarTest : public ::testing::Test {
+ public:
+  FlutterTizenTextureRegistrarTest() {
+    ecore_init();
+    elm_init(0, nullptr);
+  }
+
+ protected:
+  void SetUp() {
+    FlutterDesktopEngineProperties engine_prop = {};
+    engine_prop.assets_path = "foo/flutter_assets";
+    engine_prop.icu_data_path = "foo/icudtl.dat";
+    engine_prop.aot_library_path = "foo/libapp.so";
+
+    FlutterProjectBundle project(engine_prop);
+    auto engine = std::make_unique<FlutterTizenEngine>(project);
+    engine_ = engine.release();
+  }
+
+  void TearDown() {
+    if (engine_) {
+      delete engine_;
+    }
+    engine_ = nullptr;
+  }
+
+  FlutterTizenEngine* engine_;
+};
+
+TEST_F(FlutterTizenTextureRegistrarTest, CreateDestroy) {
+  FlutterTizenTextureRegistrar registrar(engine_);
+
+  EXPECT_TRUE(true);
+}
+
+TEST_F(FlutterTizenTextureRegistrarTest, RegisterUnregisterTexture) {
+  EngineModifier modifier(engine_);
+
+  FlutterTizenTextureRegistrar registrar(engine_);
+
+  FlutterDesktopTextureInfo texture_info = {};
+  texture_info.type = kFlutterDesktopPixelBufferTexture;
+  texture_info.pixel_buffer_config.callback =
+      [](size_t width, size_t height,
+         void* user_data) -> const FlutterDesktopPixelBuffer* {
+    return nullptr;
+  };
+
+  int64_t registered_texture_id = 0;
+  bool register_called = false;
+  modifier.embedder_api().RegisterExternalTexture = MOCK_ENGINE_PROC(
+      RegisterExternalTexture, ([&register_called, &registered_texture_id](
+                                    auto engine, auto texture_id) {
+        register_called = true;
+        registered_texture_id = texture_id;
+        return kSuccess;
+      }));
+
+  bool unregister_called = false;
+  modifier.embedder_api().UnregisterExternalTexture = MOCK_ENGINE_PROC(
+      UnregisterExternalTexture, ([&unregister_called, &registered_texture_id](
+                                      auto engine, auto texture_id) {
+        unregister_called = true;
+        EXPECT_EQ(registered_texture_id, texture_id);
+        return kSuccess;
+      }));
+
+  bool mark_frame_available_called = false;
+  modifier.embedder_api().MarkExternalTextureFrameAvailable =
+      MOCK_ENGINE_PROC(MarkExternalTextureFrameAvailable,
+                       ([&mark_frame_available_called, &registered_texture_id](
+                            auto engine, auto texture_id) {
+                         mark_frame_available_called = true;
+                         EXPECT_EQ(registered_texture_id, texture_id);
+                         return kSuccess;
+                       }));
+
+  auto texture_id = registrar.RegisterTexture(&texture_info);
+  EXPECT_TRUE(register_called);
+  EXPECT_NE(texture_id, -1);
+  EXPECT_EQ(texture_id, registered_texture_id);
+
+  EXPECT_TRUE(registrar.MarkTextureFrameAvailable(texture_id));
+  EXPECT_TRUE(mark_frame_available_called);
+
+  EXPECT_TRUE(registrar.UnregisterTexture(texture_id));
+  EXPECT_TRUE(unregister_called);
+}
+
+TEST_F(FlutterTizenTextureRegistrarTest, RegisterUnknownTextureType) {
+  EngineModifier modifier(engine_);
+
+  FlutterTizenTextureRegistrar registrar(engine_);
+
+  FlutterDesktopTextureInfo texture_info = {};
+  texture_info.type = static_cast<FlutterDesktopTextureType>(1234);
+
+  auto texture_id = registrar.RegisterTexture(&texture_info);
+
+  EXPECT_EQ(texture_id, -1);
+}
+
+TEST_F(FlutterTizenTextureRegistrarTest, PopulateInvalidTexture) {
+  FlutterTizenTextureRegistrar registrar(engine_);
+
+  auto result = registrar.PopulateTexture(1, 640, 480, nullptr);
+  EXPECT_FALSE(result);
+}
+
+}  // namespace testing
+}  // namespace flutter
diff --git a/shell/platform/tizen/testing/engine_modifier.h b/shell/platform/tizen/testing/engine_modifier.h
new file mode 100644
index 0000000000000..4075ff77abbd8
--- /dev/null
+++ b/shell/platform/tizen/testing/engine_modifier.h
@@ -0,0 +1,30 @@
+// Copyright 2021 Samsung Electronics Co., Ltd. All rights reserved.
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "flutter/shell/platform/tizen/flutter_tizen_engine.h"
+
+namespace flutter {
+
+// A test utility class providing the ability to access and alter various
+// private fields in an Engine instance.
+//
+// This simply provides a way to access the normally-private embedder proc
+// table, so the lifetime of any changes made to the proc table is that of the
+// engine object, not this helper.
+class EngineModifier {
+ public:
+  explicit EngineModifier(FlutterTizenEngine* engine) : engine_(engine) {}
+
+  // Returns the engine's embedder API proc table, allowing for modification.
+  //
+  // Modifications are to the engine, and will last for the lifetime of the
+  // engine unless overwritten again.
+  FlutterEngineProcTable& embedder_api() { return engine_->embedder_api_; }
+
+ private:
+  FlutterTizenEngine* engine_;
+};
+
+}  // namespace flutter