diff --git a/graphics/Android.bp b/graphics/Android.bp
index 6d55dd1..eaa47ae 100644
--- a/graphics/Android.bp
+++ b/graphics/Android.bp
@@ -6,6 +6,7 @@
     "common/1.0",
     "composer/2.1",
     "composer/2.1/default",
+    "composer/2.1/vts/functional",
     "mapper/2.0",
     "mapper/2.0/default",
     "mapper/2.0/vts/functional",
diff --git a/graphics/composer/2.1/vts/functional/Android.bp b/graphics/composer/2.1/vts/functional/Android.bp
new file mode 100644
index 0000000..c3f7636
--- /dev/null
+++ b/graphics/composer/2.1/vts/functional/Android.bp
@@ -0,0 +1,45 @@
+//
+// Copyright (C) 2016 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+cc_test {
+    name: "graphics_composer_hidl_hal_test",
+    gtest: true,
+    srcs: ["graphics_composer_hidl_hal_test.cpp"],
+    shared_libs: [
+        "android.hardware.graphics.allocator@2.0",
+        "android.hardware.graphics.composer@2.1",
+        "android.hardware.graphics.mapper@2.0",
+        "libbase",
+        "libcutils",
+        "libfmq",
+        "libhidlbase",
+        "libhidltransport",
+        "libhwbinder",
+        "liblog",
+        "libnativehelper",
+        "libsync",
+        "libutils",
+    ],
+    static_libs: ["libgtest", "libhwcomposer-command-buffer"],
+    cflags: [
+        "--coverage",
+        "-O0",
+        "-g",
+    ],
+    ldflags: [
+        "--coverage",
+    ],
+}
diff --git a/graphics/composer/2.1/vts/functional/graphics_composer_hidl_hal_test.cpp b/graphics/composer/2.1/vts/functional/graphics_composer_hidl_hal_test.cpp
new file mode 100644
index 0000000..e3e35bb
--- /dev/null
+++ b/graphics/composer/2.1/vts/functional/graphics_composer_hidl_hal_test.cpp
@@ -0,0 +1,1131 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "graphics_composer_hidl_hal_test"
+
+#include <IComposerCommandBuffer.h>
+#include <android-base/logging.h>
+#include <android/hardware/graphics/allocator/2.0/IAllocator.h>
+#include <android/hardware/graphics/composer/2.1/IComposer.h>
+#include <android/hardware/graphics/mapper/2.0/IMapper.h>
+
+#include <gtest/gtest.h>
+#include <unistd.h>
+
+#include <algorithm>
+#include <array>
+#include <memory>
+#include <mutex>
+#include <unordered_set>
+#include <vector>
+
+namespace android {
+namespace hardware {
+namespace graphics {
+namespace composer {
+namespace V2_1 {
+namespace tests {
+namespace {
+
+using android::hardware::graphics::allocator::V2_0::Buffer;
+using android::hardware::graphics::allocator::V2_0::BufferDescriptor;
+using android::hardware::graphics::allocator::V2_0::ConsumerUsage;
+using android::hardware::graphics::allocator::V2_0::IAllocator;
+using android::hardware::graphics::allocator::V2_0::IAllocatorClient;
+using android::hardware::graphics::allocator::V2_0::ProducerUsage;
+using android::hardware::graphics::common::V1_0::ColorMode;
+using android::hardware::graphics::common::V1_0::ColorTransform;
+using android::hardware::graphics::common::V1_0::Dataspace;
+using android::hardware::graphics::common::V1_0::PixelFormat;
+using android::hardware::graphics::common::V1_0::Transform;
+using android::hardware::graphics::mapper::V2_0::IMapper;
+using GrallocError = android::hardware::graphics::allocator::V2_0::Error;
+
+// IComposerCallback to be installed with IComposerClient::registerCallback.
+class GraphicsComposerCallback : public IComposerCallback {
+ public:
+  void setVsyncAllowed(bool allowed) {
+    std::lock_guard<std::mutex> lock(mMutex);
+    mVsyncAllowed = allowed;
+  }
+
+  std::vector<Display> getDisplays() const {
+    std::lock_guard<std::mutex> lock(mMutex);
+    return std::vector<Display>(mDisplays.begin(), mDisplays.end());
+  }
+
+  int getInvalidHotplugCount() const {
+    std::lock_guard<std::mutex> lock(mMutex);
+    return mInvalidHotplugCount;
+  }
+
+  int getInvalidRefreshCount() const {
+    std::lock_guard<std::mutex> lock(mMutex);
+    return mInvalidRefreshCount;
+  }
+
+  int getInvalidVsyncCount() const {
+    std::lock_guard<std::mutex> lock(mMutex);
+    return mInvalidVsyncCount;
+  }
+
+ private:
+  Return<void> onHotplug(Display display, Connection connection) override {
+    std::lock_guard<std::mutex> lock(mMutex);
+
+    if (connection == Connection::CONNECTED) {
+      if (!mDisplays.insert(display).second) {
+        mInvalidHotplugCount++;
+      }
+    } else if (connection == Connection::DISCONNECTED) {
+      if (!mDisplays.erase(display)) {
+        mInvalidHotplugCount++;
+      }
+    }
+
+    return Void();
+  }
+
+  Return<void> onRefresh(Display display) override {
+    std::lock_guard<std::mutex> lock(mMutex);
+
+    if (mDisplays.count(display) == 0) {
+      mInvalidRefreshCount++;
+    }
+
+    return Void();
+  }
+
+  Return<void> onVsync(Display display, int64_t) override {
+    std::lock_guard<std::mutex> lock(mMutex);
+
+    if (!mVsyncAllowed || mDisplays.count(display) == 0) {
+      mInvalidVsyncCount++;
+    }
+
+    return Void();
+  }
+
+  mutable std::mutex mMutex;
+  // the set of all currently connected displays
+  std::unordered_set<Display> mDisplays;
+  // true only when vsync is enabled
+  bool mVsyncAllowed = false;
+
+  // track invalid callbacks
+  int mInvalidHotplugCount = 0;
+  int mInvalidRefreshCount = 0;
+  int mInvalidVsyncCount = 0;
+};
+
+class GraphicsComposerHidlTest : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    mComposer = IComposer::getService("hwcomposer");
+    ASSERT_NE(nullptr, mComposer.get());
+
+    mComposerClient = createClient();
+    ASSERT_NE(nullptr, mComposerClient.get());
+
+    initCapabilities();
+
+    mComposerCallback = new GraphicsComposerCallback;
+    mComposerClient->registerCallback(mComposerCallback);
+
+    // assume the first display is primary and is never removed
+    mPrimaryDisplay = waitForFirstDisplay();
+  }
+
+  void TearDown() override {
+    if (mComposerCallback != nullptr) {
+      EXPECT_EQ(0, mComposerCallback->getInvalidHotplugCount());
+      EXPECT_EQ(0, mComposerCallback->getInvalidRefreshCount());
+      EXPECT_EQ(0, mComposerCallback->getInvalidVsyncCount());
+    }
+  }
+
+  /**
+   * Initialize the set of supported capabilities.
+   */
+  void initCapabilities() {
+    mComposer->getCapabilities([this](const auto& capabilities) {
+      std::vector<IComposer::Capability> caps = capabilities;
+      mCapabilities.insert(caps.cbegin(), caps.cend());
+    });
+  }
+
+  /**
+   * Test whether a capability is supported.
+   */
+  bool hasCapability(IComposer::Capability capability) const {
+    return (mCapabilities.count(capability) > 0);
+  }
+
+  IComposerClient::DisplayType getDisplayType(Display display) {
+    IComposerClient::DisplayType type = IComposerClient::DisplayType::INVALID;
+    mComposerClient->getDisplayType(
+        display, [&](const auto& tmpError, const auto& tmpType) {
+          ASSERT_EQ(Error::NONE, tmpError);
+          type = tmpType;
+        });
+    return type;
+  }
+
+  Error createVirtualDisplay(Display* outDisplay) {
+    auto ret_count = mComposerClient->getMaxVirtualDisplayCount();
+    if (ret_count == 0) {
+      return Error::UNSUPPORTED;
+    }
+
+    Error err = Error::NO_RESOURCES;
+    Display display;
+    mComposerClient->createVirtualDisplay(
+        64, 64, PixelFormat::IMPLEMENTATION_DEFINED, kBufferSlotCount,
+        [&](const auto& tmpError, const auto& tmpDisplay, const auto&) {
+          err = tmpError;
+          display = tmpDisplay;
+        });
+
+    *outDisplay = display;
+    return err;
+  }
+
+  void destroyVirtualDisplay(Display display) {
+    auto ret = mComposerClient->destroyVirtualDisplay(display);
+    ASSERT_EQ(Error::NONE, static_cast<Error>(ret));
+  }
+
+  Error createLayer(Layer* outLayer) {
+    Error err = Error::NO_RESOURCES;
+    Layer layer;
+    mComposerClient->createLayer(
+        mPrimaryDisplay, kBufferSlotCount,
+        [&](const auto& tmpError, const auto& tmpLayer) {
+          err = tmpError;
+          layer = tmpLayer;
+        });
+
+    *outLayer = layer;
+    return err;
+  }
+
+  void destroyLayer(Layer layer) {
+    auto ret = mComposerClient->destroyLayer(mPrimaryDisplay, layer);
+    ASSERT_EQ(Error::NONE, static_cast<Error>(ret));
+  }
+
+  int32_t getDisplayAttribute(Config config,
+                              IComposerClient::Attribute attribute) {
+    int32_t value = -1;
+    mComposerClient->getDisplayAttribute(
+        mPrimaryDisplay, config, attribute,
+        [&](const auto& tmpError, const auto& tmpValue) {
+          ASSERT_EQ(Error::NONE, tmpError);
+          value = tmpValue;
+        });
+    return value;
+  }
+
+  std::vector<Config> getDisplayConfigs() {
+    std::vector<Config> configs;
+    mComposerClient->getDisplayConfigs(
+        mPrimaryDisplay, [&](const auto& tmpError, const auto& tmpConfigs) {
+          ASSERT_EQ(Error::NONE, tmpError);
+
+          configs = tmpConfigs;
+          ASSERT_FALSE(configs.empty());
+        });
+
+    return configs;
+  }
+
+  std::vector<ColorMode> getColorModes() {
+    std::vector<ColorMode> modes;
+    mComposerClient->getColorModes(
+        mPrimaryDisplay, [&](const auto& tmpError, const auto& tmpModes) {
+          ASSERT_EQ(Error::NONE, tmpError);
+
+          modes = tmpModes;
+          ASSERT_NE(modes.end(),
+                    std::find(modes.begin(), modes.end(), ColorMode::NATIVE));
+        });
+
+    return modes;
+  }
+
+  std::vector<IComposerClient::PowerMode> getPowerModes() {
+    std::vector<IComposerClient::PowerMode> modes;
+    modes.push_back(IComposerClient::PowerMode::OFF);
+
+    mComposerClient->getDozeSupport(
+        mPrimaryDisplay, [&](const auto& tmpError, const auto& tmpSupport) {
+          ASSERT_EQ(Error::NONE, tmpError);
+          if (tmpSupport) {
+            modes.push_back(IComposerClient::PowerMode::DOZE);
+            modes.push_back(IComposerClient::PowerMode::DOZE_SUSPEND);
+          }
+        });
+
+    // push ON last
+    modes.push_back(IComposerClient::PowerMode::ON);
+
+    return modes;
+  }
+
+  void setActiveConfig(Config config) {
+    auto ret = mComposerClient->setActiveConfig(mPrimaryDisplay, config);
+    ASSERT_EQ(Error::NONE, static_cast<Error>(ret));
+  }
+
+  void setColorMode(ColorMode mode) {
+    auto ret = mComposerClient->setColorMode(mPrimaryDisplay, mode);
+    ASSERT_EQ(Error::NONE, static_cast<Error>(ret));
+  }
+
+  void setPowerMode(IComposerClient::PowerMode mode) {
+    auto ret = mComposerClient->setPowerMode(mPrimaryDisplay, mode);
+    ASSERT_EQ(Error::NONE, static_cast<Error>(ret));
+  }
+
+  void setVsyncEnabled(bool enable) {
+    auto ret = mComposerClient->setVsyncEnabled(
+        mPrimaryDisplay,
+        enable ? IComposerClient::Vsync::ENABLE
+               : IComposerClient::Vsync::DISABLE);
+    ASSERT_EQ(Error::NONE, static_cast<Error>(ret));
+  }
+  // use the slot count usually set by SF
+  static constexpr uint32_t kBufferSlotCount = 64;
+
+  sp<IComposer> mComposer;
+  sp<IComposerClient> mComposerClient;
+  sp<GraphicsComposerCallback> mComposerCallback;
+  // the first display and is assumed never to be removed
+  Display mPrimaryDisplay;
+
+ private:
+  sp<IComposerClient> createClient() {
+    sp<IComposerClient> client;
+    mComposer->createClient([&](const auto& tmpError, const auto& tmpClient) {
+      if (tmpError == Error::NONE) {
+        client = tmpClient;
+      }
+    });
+
+    return client;
+  }
+
+  Display waitForFirstDisplay() {
+    while (true) {
+      std::vector<Display> displays = mComposerCallback->getDisplays();
+      if (displays.empty()) {
+        usleep(5 * 1000);
+        continue;
+      }
+
+      return displays[0];
+    }
+  }
+
+  // the set of all supported capabilities
+  std::unordered_set<IComposer::Capability> mCapabilities;
+};
+
+/**
+ * Test IComposer::getCapabilities.
+ *
+ * Test that IComposer::getCapabilities returns no invalid capabilities.
+ */
+TEST_F(GraphicsComposerHidlTest, GetCapabilities) {
+  mComposer->getCapabilities([](const auto& tmpCapabilities) {
+    std::vector<IComposer::Capability> capabilities = tmpCapabilities;
+    ASSERT_EQ(capabilities.end(),
+              std::find(capabilities.begin(), capabilities.end(),
+                        IComposer::Capability::INVALID));
+  });
+}
+
+/**
+ * Test IComposer::dumpDebugInfo.
+ */
+TEST_F(GraphicsComposerHidlTest, DumpDebugInfo) {
+  mComposer->dumpDebugInfo([](const auto&) {
+    // nothing to do
+  });
+}
+
+/**
+ * Test IComposer::createClient.
+ *
+ * Test that IComposerClient is a singleton.
+ */
+TEST_F(GraphicsComposerHidlTest, CreateClientSingleton) {
+  mComposer->createClient([&](const auto& tmpError, const auto&) {
+    EXPECT_EQ(Error::NO_RESOURCES, tmpError);
+  });
+}
+
+/**
+ * Test IComposerClient::createVirtualDisplay and
+ * IComposerClient::destroyVirtualDisplay.
+ *
+ * Test that virtual displays can be created and has the correct display type.
+ */
+TEST_F(GraphicsComposerHidlTest, CreateVirtualDisplay) {
+  Display display;
+  Error err = createVirtualDisplay(&display);
+  if (err == Error::UNSUPPORTED) {
+    GTEST_SUCCEED() << "no virtual display support";
+    return;
+  }
+  ASSERT_EQ(Error::NONE, err);
+
+  // test display type
+  IComposerClient::DisplayType type = getDisplayType(display);
+  EXPECT_EQ(IComposerClient::DisplayType::VIRTUAL, type);
+
+  destroyVirtualDisplay(display);
+}
+
+/**
+ * Test IComposerClient::createLayer and IComposerClient::destroyLayer.
+ *
+ * Test that layers can be created and destroyed.
+ */
+TEST_F(GraphicsComposerHidlTest, CreateLayer) {
+  Layer layer;
+  Error err = createLayer(&layer);
+  ASSERT_EQ(Error::NONE, err);
+
+  destroyLayer(layer);
+}
+
+/**
+ * Test IComposerClient::getDisplayName.
+ */
+TEST_F(GraphicsComposerHidlTest, GetDisplayName) {
+  mComposerClient->getDisplayName(mPrimaryDisplay,
+                                  [&](const auto& tmpError, const auto&) {
+                                    ASSERT_EQ(Error::NONE, tmpError);
+                                  });
+}
+
+/**
+ * Test IComposerClient::getDisplayType.
+ *
+ * Test that IComposerClient::getDisplayType returns the correct display type
+ * for the primary display.
+ */
+TEST_F(GraphicsComposerHidlTest, GetDisplayType) {
+  IComposerClient::DisplayType type = getDisplayType(mPrimaryDisplay);
+  EXPECT_EQ(IComposerClient::DisplayType::PHYSICAL, type);
+}
+
+/**
+ * Test IComposerClient::getClientTargetSupport.
+ *
+ * Test that IComposerClient::getClientTargetSupport returns true for the
+ * required client targets.
+ */
+TEST_F(GraphicsComposerHidlTest, GetClientTargetSupport) {
+  std::vector<Config> configs = getDisplayConfigs();
+  for (auto config : configs) {
+    int32_t width =
+        getDisplayAttribute(config, IComposerClient::Attribute::WIDTH);
+    int32_t height =
+        getDisplayAttribute(config, IComposerClient::Attribute::HEIGHT);
+    ASSERT_LT(0, width);
+    ASSERT_LT(0, height);
+
+    setActiveConfig(config);
+
+    auto ret = mComposerClient->getClientTargetSupport(
+        mPrimaryDisplay, width, height, PixelFormat::RGBA_8888,
+        Dataspace::UNKNOWN);
+    ASSERT_EQ(Error::NONE, static_cast<Error>(ret));
+  }
+}
+
+/**
+ * Test IComposerClient::getDisplayAttribute.
+ *
+ * Test that IComposerClient::getDisplayAttribute succeeds for the required
+ * formats, and succeeds or fails correctly for optional attributes.
+ */
+TEST_F(GraphicsComposerHidlTest, GetDisplayAttribute) {
+  std::vector<Config> configs = getDisplayConfigs();
+  for (auto config : configs) {
+    const std::array<IComposerClient::Attribute, 3> requiredAttributes = {{
+        IComposerClient::Attribute::WIDTH, IComposerClient::Attribute::HEIGHT,
+        IComposerClient::Attribute::VSYNC_PERIOD,
+    }};
+    for (auto attribute : requiredAttributes) {
+      getDisplayAttribute(config, attribute);
+    }
+
+    const std::array<IComposerClient::Attribute, 2> optionalAttributes = {{
+        IComposerClient::Attribute::DPI_X, IComposerClient::Attribute::DPI_Y,
+    }};
+    for (auto attribute : optionalAttributes) {
+      mComposerClient->getDisplayAttribute(
+          mPrimaryDisplay, config, attribute,
+          [&](const auto& tmpError, const auto&) {
+            EXPECT_TRUE(tmpError == Error::NONE ||
+                        tmpError == Error::UNSUPPORTED);
+          });
+    }
+  }
+}
+
+/**
+ * Test IComposerClient::getHdrCapabilities.
+ */
+TEST_F(GraphicsComposerHidlTest, GetHdrCapabilities) {
+  mComposerClient->getHdrCapabilities(
+      mPrimaryDisplay,
+      [&](const auto& tmpError, const auto&, const auto&, const auto&,
+          const auto&) { ASSERT_EQ(Error::NONE, tmpError); });
+}
+
+/**
+ * Test IComposerClient::setClientTargetSlotCount.
+ */
+TEST_F(GraphicsComposerHidlTest, SetClientTargetSlotCount) {
+  auto ret = mComposerClient->setClientTargetSlotCount(mPrimaryDisplay,
+                                                       kBufferSlotCount);
+  ASSERT_EQ(Error::NONE, static_cast<Error>(ret));
+}
+
+/**
+ * Test IComposerClient::setActiveConfig.
+ *
+ * Test that IComposerClient::setActiveConfig succeeds for all display
+ * configs.
+ */
+TEST_F(GraphicsComposerHidlTest, SetActiveConfig) {
+  std::vector<Config> configs = getDisplayConfigs();
+  for (auto config : configs) {
+    setActiveConfig(config);
+
+    mComposerClient->getActiveConfig(
+        mPrimaryDisplay, [&](const auto& tmpError, const auto& tmpConfig) {
+          EXPECT_EQ(Error::NONE, tmpError);
+          EXPECT_EQ(config, tmpConfig);
+        });
+  }
+}
+
+/**
+ * Test IComposerClient::setColorMode.
+ *
+ * Test that IComposerClient::setColorMode succeeds for all color modes.
+ */
+TEST_F(GraphicsComposerHidlTest, SetColorMode) {
+  std::vector<ColorMode> modes = getColorModes();
+  for (auto mode : modes) {
+    setColorMode(mode);
+  }
+}
+
+/**
+ * Test IComposerClient::setPowerMode.
+ *
+ * Test that IComposerClient::setPowerMode succeeds for all power modes.
+ */
+TEST_F(GraphicsComposerHidlTest, SetPowerMode) {
+  std::vector<IComposerClient::PowerMode> modes = getPowerModes();
+  for (auto mode : modes) {
+    setPowerMode(mode);
+  }
+}
+
+/**
+ * Test IComposerClient::setVsyncEnabled.
+ *
+ * Test that IComposerClient::setVsyncEnabled succeeds and there is no
+ * spurious vsync events.
+ */
+TEST_F(GraphicsComposerHidlTest, SetVsyncEnabled) {
+  mComposerCallback->setVsyncAllowed(true);
+
+  setVsyncEnabled(true);
+  usleep(60 * 1000);
+  setVsyncEnabled(false);
+
+  mComposerCallback->setVsyncAllowed(false);
+}
+
+// Tests for IComposerClient::Command.
+class GraphicsComposerHidlCommandTest : public GraphicsComposerHidlTest {
+ protected:
+  void SetUp() override {
+    ASSERT_NO_FATAL_FAILURE(GraphicsComposerHidlTest::SetUp());
+    ASSERT_NO_FATAL_FAILURE(SetUpGralloc());
+
+    mWriter = std::make_unique<CommandWriterBase>(1024);
+    mReader = std::make_unique<CommandReader>();
+  }
+
+  void TearDown() override {
+    ASSERT_NO_FATAL_FAILURE(GraphicsComposerHidlTest::TearDown());
+  }
+
+  const native_handle_t* cloneBuffer(const native_handle_t* handle) {
+    auto clone = native_handle_clone(handle);
+    if (!clone) {
+      return nullptr;
+    }
+
+    GrallocError err = mMapper->retain(clone);
+    if (err != GrallocError::NONE) {
+      native_handle_close(clone);
+      native_handle_delete(const_cast<native_handle_t*>(clone));
+      return nullptr;
+    }
+
+    return clone;
+  }
+
+  const native_handle_t* allocate(
+      const IAllocatorClient::BufferDescriptorInfo& info) {
+    // create descriptor
+    GrallocError err = GrallocError::NO_RESOURCES;
+    BufferDescriptor descriptor;
+    mAllocatorClient->createDescriptor(
+        info, [&](const auto& tmpError, const auto& tmpDescriptor) {
+          err = tmpError;
+          descriptor = tmpDescriptor;
+        });
+    if (err != GrallocError::NONE) {
+      return nullptr;
+    }
+
+    // allocate buffer
+    hidl_vec<BufferDescriptor> descriptors;
+    hidl_vec<Buffer> buffers;
+    descriptors.setToExternal(&descriptor, 1);
+    err = GrallocError::NO_RESOURCES;
+    mAllocatorClient->allocate(
+        descriptors, [&](const auto& tmpError, const auto& tmpBuffers) {
+          err = tmpError;
+          buffers = tmpBuffers;
+        });
+    if ((err != GrallocError::NONE && err != GrallocError::NOT_SHARED) ||
+        buffers.size() != 1) {
+      mAllocatorClient->destroyDescriptor(descriptors[0]);
+      return nullptr;
+    }
+
+    // export handle
+    err = GrallocError::NO_RESOURCES;
+    const native_handle_t* handle = nullptr;
+    mAllocatorClient->exportHandle(
+        descriptors[0], buffers[0],
+        [&](const auto& tmpError, const auto& tmpHandle) {
+          err = tmpError;
+          if (err != GrallocError::NONE) {
+            return;
+          }
+
+          handle = cloneBuffer(tmpHandle.getNativeHandle());
+          if (!handle) {
+            err = GrallocError::NO_RESOURCES;
+            return;
+          }
+        });
+
+    mAllocatorClient->destroyDescriptor(descriptors[0]);
+    mAllocatorClient->free(buffers[0]);
+
+    if (err != GrallocError::NONE) {
+      return nullptr;
+    }
+
+    return handle;
+  }
+
+  const native_handle_t* allocate() {
+    IAllocatorClient::BufferDescriptorInfo info{};
+    info.width = 64;
+    info.height = 64;
+    info.layerCount = 1;
+    info.format = PixelFormat::RGBA_8888;
+    info.producerUsageMask = static_cast<uint64_t>(ProducerUsage::CPU_WRITE);
+    info.consumerUsageMask = static_cast<uint64_t>(ConsumerUsage::CPU_READ);
+
+    return allocate(info);
+  }
+
+  void free(const native_handle_t* handle) {
+    auto ret = mMapper->release(handle);
+    ASSERT_EQ(GrallocError::NONE, static_cast<GrallocError>(ret));
+  }
+
+  void execute() {
+    bool queueChanged = false;
+    uint32_t commandLength = 0;
+    hidl_vec<hidl_handle> commandHandles;
+    ASSERT_TRUE(
+        mWriter->writeQueue(&queueChanged, &commandLength, &commandHandles));
+
+    if (queueChanged) {
+      auto ret =
+          mComposerClient->setInputCommandQueue(*mWriter->getMQDescriptor());
+      ASSERT_EQ(Error::NONE, static_cast<Error>(ret));
+      return;
+    }
+
+    mComposerClient->executeCommands(
+        commandLength, commandHandles,
+        [&](const auto& tmpError, const auto& tmpOutQueueChanged,
+            const auto& tmpOutLength, const auto& tmpOutHandles) {
+          ASSERT_EQ(Error::NONE, tmpError);
+
+          if (tmpOutQueueChanged) {
+            mComposerClient->getOutputCommandQueue(
+                [&](const auto& tmpError, const auto& tmpDescriptor) {
+                  ASSERT_EQ(Error::NONE, tmpError);
+                  mReader->setMQDescriptor(tmpDescriptor);
+                });
+          }
+
+          ASSERT_TRUE(mReader->readQueue(tmpOutLength, tmpOutHandles));
+          mReader->parse();
+        });
+  }
+
+  // A command parser that checks that no error nor unexpected commands are
+  // returned.
+  class CommandReader : public CommandReaderBase {
+   public:
+    // Parse all commands in the return command queue.  Call GTEST_FAIL() for
+    // unexpected errors or commands.
+    void parse() {
+      while (!isEmpty()) {
+        IComposerClient::Command command;
+        uint16_t length;
+        ASSERT_TRUE(beginCommand(&command, &length));
+
+        switch (command) {
+          case IComposerClient::Command::SET_ERROR: {
+            ASSERT_EQ(2, length);
+            auto loc = read();
+            auto err = readSigned();
+            GTEST_FAIL() << "unexpected error " << err << " at location "
+                         << loc;
+          } break;
+          case IComposerClient::Command::SELECT_DISPLAY:
+          case IComposerClient::Command::SET_CHANGED_COMPOSITION_TYPES:
+          case IComposerClient::Command::SET_DISPLAY_REQUESTS:
+          case IComposerClient::Command::SET_PRESENT_FENCE:
+          case IComposerClient::Command::SET_RELEASE_FENCES:
+            break;
+          default:
+            GTEST_FAIL() << "unexpected return command " << std::hex
+                         << static_cast<int>(command);
+            break;
+        }
+
+        endCommand();
+      }
+    }
+  };
+
+  std::unique_ptr<CommandWriterBase> mWriter;
+  std::unique_ptr<CommandReader> mReader;
+
+ private:
+  void SetUpGralloc() {
+    mAllocator = IAllocator::getService("gralloc");
+    ASSERT_NE(nullptr, mAllocator.get());
+
+    mAllocator->createClient([this](const auto& error, const auto& client) {
+      if (error == GrallocError::NONE) {
+        mAllocatorClient = client;
+      }
+    });
+    ASSERT_NE(nullptr, mAllocatorClient.get());
+
+    mMapper = IMapper::getService("gralloc-mapper");
+    ASSERT_NE(nullptr, mMapper.get());
+    ASSERT_FALSE(mMapper->isRemote());
+  }
+
+  sp<IAllocator> mAllocator;
+  sp<IAllocatorClient> mAllocatorClient;
+  sp<IMapper> mMapper;
+};
+
+/**
+ * Test IComposerClient::Command::SET_COLOR_TRANSFORM.
+ */
+TEST_F(GraphicsComposerHidlCommandTest, SET_COLOR_TRANSFORM) {
+  const std::array<float, 16> identity = {{
+      1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f,
+      0.0f, 0.0f, 0.0f, 1.0f,
+  }};
+
+  mWriter->selectDisplay(mPrimaryDisplay);
+  mWriter->setColorTransform(identity.data(), ColorTransform::IDENTITY);
+
+  execute();
+}
+
+/**
+ * Test IComposerClient::Command::SET_CLIENT_TARGET.
+ */
+TEST_F(GraphicsComposerHidlCommandTest, SET_CLIENT_TARGET) {
+  mComposerClient->setClientTargetSlotCount(mPrimaryDisplay, kBufferSlotCount);
+
+  mWriter->selectDisplay(mPrimaryDisplay);
+  mWriter->setClientTarget(0, nullptr, -1, Dataspace::UNKNOWN,
+                           std::vector<IComposerClient::Rect>());
+
+  execute();
+}
+
+/**
+ * Test IComposerClient::Command::SET_OUTPUT_BUFFER.
+ */
+TEST_F(GraphicsComposerHidlCommandTest, SET_OUTPUT_BUFFER) {
+  auto handle = allocate();
+  ASSERT_NE(nullptr, handle);
+
+  Display display;
+  Error err = createVirtualDisplay(&display);
+  if (err == Error::UNSUPPORTED) {
+    GTEST_SUCCEED() << "no virtual display support";
+    return;
+  }
+  ASSERT_EQ(Error::NONE, err);
+
+  mWriter->selectDisplay(display);
+  mWriter->setOutputBuffer(0, handle, -1);
+
+  destroyVirtualDisplay(display);
+  free(handle);
+}
+
+/**
+ * Test IComposerClient::Command::VALIDATE_DISPLAY.
+ */
+TEST_F(GraphicsComposerHidlCommandTest, VALIDATE_DISPLAY) {
+  mWriter->selectDisplay(mPrimaryDisplay);
+  mWriter->validateDisplay();
+  execute();
+}
+
+/**
+ * Test IComposerClient::Command::ACCEPT_DISPLAY_CHANGES.
+ */
+TEST_F(GraphicsComposerHidlCommandTest, ACCEPT_DISPLAY_CHANGES) {
+  mWriter->selectDisplay(mPrimaryDisplay);
+  mWriter->validateDisplay();
+  mWriter->acceptDisplayChanges();
+  execute();
+}
+
+/**
+ * Test IComposerClient::Command::PRESENT_DISPLAY.
+ */
+TEST_F(GraphicsComposerHidlCommandTest, PRESENT_DISPLAY) {
+  mWriter->selectDisplay(mPrimaryDisplay);
+  mWriter->validateDisplay();
+  mWriter->presentDisplay();
+  execute();
+}
+
+/**
+ * Test IComposerClient::Command::SET_LAYER_CURSOR_POSITION.
+ */
+TEST_F(GraphicsComposerHidlCommandTest, SET_LAYER_CURSOR_POSITION) {
+  Layer layer;
+  Error err = createLayer(&layer);
+  ASSERT_EQ(Error::NONE, err);
+
+  mWriter->selectDisplay(mPrimaryDisplay);
+  mWriter->selectLayer(layer);
+  mWriter->setLayerCursorPosition(1, 1);
+  mWriter->setLayerCursorPosition(0, 0);
+  execute();
+
+  destroyLayer(layer);
+}
+
+/**
+ * Test IComposerClient::Command::SET_LAYER_BUFFER.
+ */
+TEST_F(GraphicsComposerHidlCommandTest, SET_LAYER_BUFFER) {
+  auto handle = allocate();
+  ASSERT_NE(nullptr, handle);
+
+  Layer layer;
+  Error err = createLayer(&layer);
+  ASSERT_EQ(Error::NONE, err);
+
+  mWriter->selectDisplay(mPrimaryDisplay);
+  mWriter->selectLayer(layer);
+  mWriter->setLayerBuffer(0, handle, -1);
+  execute();
+
+  destroyLayer(layer);
+  free(handle);
+}
+
+/**
+ * Test IComposerClient::Command::SET_LAYER_SURFACE_DAMAGE.
+ */
+TEST_F(GraphicsComposerHidlCommandTest, SET_LAYER_SURFACE_DAMAGE) {
+  Layer layer;
+  Error err = createLayer(&layer);
+  ASSERT_EQ(Error::NONE, err);
+
+  IComposerClient::Rect empty{0, 0, 0, 0};
+  IComposerClient::Rect unit{0, 0, 1, 1};
+
+  mWriter->selectDisplay(mPrimaryDisplay);
+  mWriter->selectLayer(layer);
+  mWriter->setLayerSurfaceDamage(std::vector<IComposerClient::Rect>(1, empty));
+  mWriter->setLayerSurfaceDamage(std::vector<IComposerClient::Rect>(1, unit));
+  mWriter->setLayerSurfaceDamage(std::vector<IComposerClient::Rect>());
+  execute();
+
+  destroyLayer(layer);
+}
+
+/**
+ * Test IComposerClient::Command::SET_LAYER_BLEND_MODE.
+ */
+TEST_F(GraphicsComposerHidlCommandTest, SET_LAYER_BLEND_MODE) {
+  Layer layer;
+  Error err = createLayer(&layer);
+  ASSERT_EQ(Error::NONE, err);
+
+  mWriter->selectDisplay(mPrimaryDisplay);
+  mWriter->selectLayer(layer);
+  mWriter->setLayerBlendMode(IComposerClient::BlendMode::NONE);
+  mWriter->setLayerBlendMode(IComposerClient::BlendMode::PREMULTIPLIED);
+  mWriter->setLayerBlendMode(IComposerClient::BlendMode::COVERAGE);
+  execute();
+
+  destroyLayer(layer);
+}
+
+/**
+ * Test IComposerClient::Command::SET_LAYER_COLOR.
+ */
+TEST_F(GraphicsComposerHidlCommandTest, SET_LAYER_COLOR) {
+  Layer layer;
+  Error err = createLayer(&layer);
+  ASSERT_EQ(Error::NONE, err);
+
+  mWriter->selectDisplay(mPrimaryDisplay);
+  mWriter->selectLayer(layer);
+  mWriter->setLayerColor(IComposerClient::Color{0xff, 0xff, 0xff, 0xff});
+  mWriter->setLayerColor(IComposerClient::Color{0, 0, 0, 0});
+  execute();
+
+  destroyLayer(layer);
+}
+
+/**
+ * Test IComposerClient::Command::SET_LAYER_COMPOSITION_TYPE.
+ */
+TEST_F(GraphicsComposerHidlCommandTest, SET_LAYER_COMPOSITION_TYPE) {
+  Layer layer;
+  Error err = createLayer(&layer);
+  ASSERT_EQ(Error::NONE, err);
+
+  mWriter->selectDisplay(mPrimaryDisplay);
+  mWriter->selectLayer(layer);
+  mWriter->setLayerCompositionType(IComposerClient::Composition::CLIENT);
+  mWriter->setLayerCompositionType(IComposerClient::Composition::DEVICE);
+  mWriter->setLayerCompositionType(IComposerClient::Composition::SOLID_COLOR);
+  mWriter->setLayerCompositionType(IComposerClient::Composition::CURSOR);
+  execute();
+
+  destroyLayer(layer);
+}
+
+/**
+ * Test IComposerClient::Command::SET_LAYER_DATASPACE.
+ */
+TEST_F(GraphicsComposerHidlCommandTest, SET_LAYER_DATASPACE) {
+  Layer layer;
+  Error err = createLayer(&layer);
+  ASSERT_EQ(Error::NONE, err);
+
+  mWriter->selectDisplay(mPrimaryDisplay);
+  mWriter->selectLayer(layer);
+  mWriter->setLayerDataspace(Dataspace::UNKNOWN);
+  execute();
+
+  destroyLayer(layer);
+}
+
+/**
+ * Test IComposerClient::Command::SET_LAYER_DISPLAY_FRAME.
+ */
+TEST_F(GraphicsComposerHidlCommandTest, SET_LAYER_DISPLAY_FRAME) {
+  Layer layer;
+  Error err = createLayer(&layer);
+  ASSERT_EQ(Error::NONE, err);
+
+  mWriter->selectDisplay(mPrimaryDisplay);
+  mWriter->selectLayer(layer);
+  mWriter->setLayerDisplayFrame(IComposerClient::Rect{0, 0, 1, 1});
+  execute();
+
+  destroyLayer(layer);
+}
+
+/**
+ * Test IComposerClient::Command::SET_LAYER_PLANE_ALPHA.
+ */
+TEST_F(GraphicsComposerHidlCommandTest, SET_LAYER_PLANE_ALPHA) {
+  Layer layer;
+  Error err = createLayer(&layer);
+  ASSERT_EQ(Error::NONE, err);
+
+  mWriter->selectDisplay(mPrimaryDisplay);
+  mWriter->selectLayer(layer);
+  mWriter->setLayerPlaneAlpha(0.0f);
+  mWriter->setLayerPlaneAlpha(1.0f);
+  execute();
+
+  destroyLayer(layer);
+}
+
+/**
+ * Test IComposerClient::Command::SET_LAYER_SIDEBAND_STREAM.
+ */
+TEST_F(GraphicsComposerHidlCommandTest, SET_LAYER_SIDEBAND_STREAM) {
+  if (!hasCapability(IComposer::Capability::SIDEBAND_STREAM)) {
+    GTEST_SUCCEED() << "no sideband stream support";
+    return;
+  }
+
+  auto handle = allocate();
+  ASSERT_NE(nullptr, handle);
+
+  Layer layer;
+  Error err = createLayer(&layer);
+  ASSERT_EQ(Error::NONE, err);
+
+  mWriter->selectDisplay(mPrimaryDisplay);
+  mWriter->selectLayer(layer);
+  mWriter->setLayerSidebandStream(handle);
+  execute();
+
+  destroyLayer(layer);
+  free(handle);
+}
+
+/**
+ * Test IComposerClient::Command::SET_LAYER_SOURCE_CROP.
+ */
+TEST_F(GraphicsComposerHidlCommandTest, SET_LAYER_SOURCE_CROP) {
+  Layer layer;
+  Error err = createLayer(&layer);
+  ASSERT_EQ(Error::NONE, err);
+
+  mWriter->selectDisplay(mPrimaryDisplay);
+  mWriter->selectLayer(layer);
+  mWriter->setLayerSourceCrop(IComposerClient::FRect{0.0f, 0.0f, 1.0f, 1.0f});
+  execute();
+
+  destroyLayer(layer);
+}
+
+/**
+ * Test IComposerClient::Command::SET_LAYER_TRANSFORM.
+ */
+TEST_F(GraphicsComposerHidlCommandTest, SET_LAYER_TRANSFORM) {
+  Layer layer;
+  Error err = createLayer(&layer);
+  ASSERT_EQ(Error::NONE, err);
+
+  mWriter->selectDisplay(mPrimaryDisplay);
+  mWriter->selectLayer(layer);
+  mWriter->setLayerTransform(static_cast<Transform>(0));
+  mWriter->setLayerTransform(Transform::FLIP_H);
+  mWriter->setLayerTransform(Transform::FLIP_V);
+  mWriter->setLayerTransform(Transform::ROT_90);
+  mWriter->setLayerTransform(Transform::ROT_180);
+  mWriter->setLayerTransform(Transform::ROT_270);
+  mWriter->setLayerTransform(
+      static_cast<Transform>(Transform::FLIP_H | Transform::ROT_90));
+  mWriter->setLayerTransform(
+      static_cast<Transform>(Transform::FLIP_V | Transform::ROT_90));
+  execute();
+
+  destroyLayer(layer);
+}
+
+/**
+ * Test IComposerClient::Command::SET_LAYER_VISIBLE_REGION.
+ */
+TEST_F(GraphicsComposerHidlCommandTest, SET_LAYER_VISIBLE_REGION) {
+  Layer layer;
+  Error err = createLayer(&layer);
+  ASSERT_EQ(Error::NONE, err);
+
+  IComposerClient::Rect empty{0, 0, 0, 0};
+  IComposerClient::Rect unit{0, 0, 1, 1};
+
+  mWriter->selectDisplay(mPrimaryDisplay);
+  mWriter->selectLayer(layer);
+  mWriter->setLayerVisibleRegion(std::vector<IComposerClient::Rect>(1, empty));
+  mWriter->setLayerVisibleRegion(std::vector<IComposerClient::Rect>(1, unit));
+  mWriter->setLayerVisibleRegion(std::vector<IComposerClient::Rect>());
+  execute();
+
+  destroyLayer(layer);
+}
+
+/**
+ * Test IComposerClient::Command::SET_LAYER_Z_ORDER.
+ */
+TEST_F(GraphicsComposerHidlCommandTest, SET_LAYER_Z_ORDER) {
+  Layer layer;
+  Error err = createLayer(&layer);
+  ASSERT_EQ(Error::NONE, err);
+
+  mWriter->selectDisplay(mPrimaryDisplay);
+  mWriter->selectLayer(layer);
+  mWriter->setLayerZOrder(10);
+  mWriter->setLayerZOrder(0);
+  execute();
+
+  destroyLayer(layer);
+}
+
+}  // namespace anonymous
+}  // namespace tests
+}  // namespace V2_1
+}  // namespace composer
+}  // namespace graphics
+}  // namespace hardware
+}  // namespace android
+
+int main(int argc, char** argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+
+  int status = RUN_ALL_TESTS();
+  LOG(INFO) << "Test result = " << status;
+
+  return status;
+}