diff --git a/services/surfaceflinger/tests/unittests/Android.bp b/services/surfaceflinger/tests/unittests/Android.bp
index 1b25a36..736ef30 100644
--- a/services/surfaceflinger/tests/unittests/Android.bp
+++ b/services/surfaceflinger/tests/unittests/Android.bp
@@ -57,6 +57,7 @@
         "FpsTest.cpp",
         "FramebufferSurfaceTest.cpp",
         "FrameTimelineTest.cpp",
+        "GameModeTest.cpp",
         "HWComposerTest.cpp",
         "OneShotTimerTest.cpp",
         "LayerHistoryTest.cpp",
diff --git a/services/surfaceflinger/tests/unittests/GameModeTest.cpp b/services/surfaceflinger/tests/unittests/GameModeTest.cpp
new file mode 100644
index 0000000..3fa1a2c
--- /dev/null
+++ b/services/surfaceflinger/tests/unittests/GameModeTest.cpp
@@ -0,0 +1,159 @@
+/*
+ * Copyright 2021 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.
+ */
+
+#undef LOG_TAG
+#define LOG_TAG "LibSurfaceFlingerUnittests"
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include <gui/LayerMetadata.h>
+#include <gui/SurfaceComposerClient.h>
+#include <log/log.h>
+
+#include "TestableSurfaceFlinger.h"
+#include "mock/DisplayHardware/MockComposer.h"
+#include "mock/MockEventThread.h"
+#include "mock/MockVsyncController.h"
+
+namespace android {
+
+using testing::_;
+using testing::Mock;
+using testing::Return;
+using FakeHwcDisplayInjector = TestableSurfaceFlinger::FakeHwcDisplayInjector;
+
+class GameModeTest : public testing::Test {
+public:
+    GameModeTest() {
+        const ::testing::TestInfo* const test_info =
+                ::testing::UnitTest::GetInstance()->current_test_info();
+        ALOGD("**** Setting up for %s.%s\n", test_info->test_case_name(), test_info->name());
+        setupScheduler();
+        setupComposer();
+    }
+
+    ~GameModeTest() {
+        const ::testing::TestInfo* const test_info =
+                ::testing::UnitTest::GetInstance()->current_test_info();
+        ALOGD("**** Tearing down after %s.%s\n", test_info->test_case_name(), test_info->name());
+    }
+
+    sp<BufferStateLayer> createBufferStateLayer() {
+        sp<Client> client;
+        LayerCreationArgs args(mFlinger.flinger(), client, "buffer-state-layer", 100, 100, 0,
+                               LayerMetadata());
+        return new BufferStateLayer(args);
+    }
+
+    void setupScheduler() {
+        auto eventThread = std::make_unique<mock::EventThread>();
+        auto sfEventThread = std::make_unique<mock::EventThread>();
+
+        EXPECT_CALL(*eventThread, registerDisplayEventConnection(_));
+        EXPECT_CALL(*eventThread, createEventConnection(_, _))
+                .WillOnce(Return(new EventThreadConnection(eventThread.get(), /*callingUid=*/0,
+                                                           ResyncCallback())));
+
+        EXPECT_CALL(*sfEventThread, registerDisplayEventConnection(_));
+        EXPECT_CALL(*sfEventThread, createEventConnection(_, _))
+                .WillOnce(Return(new EventThreadConnection(sfEventThread.get(), /*callingUid=*/0,
+                                                           ResyncCallback())));
+
+        auto vsyncController = std::make_unique<mock::VsyncController>();
+        auto vsyncTracker = std::make_unique<mock::VSyncTracker>();
+
+        EXPECT_CALL(*vsyncTracker, nextAnticipatedVSyncTimeFrom(_)).WillRepeatedly(Return(0));
+        EXPECT_CALL(*vsyncTracker, currentPeriod())
+                .WillRepeatedly(Return(FakeHwcDisplayInjector::DEFAULT_VSYNC_PERIOD));
+        EXPECT_CALL(*vsyncTracker, nextAnticipatedVSyncTimeFrom(_)).WillRepeatedly(Return(0));
+        mFlinger.setupScheduler(std::move(vsyncController), std::move(vsyncTracker),
+                                std::move(eventThread), std::move(sfEventThread));
+    }
+
+    void setupComposer() {
+        mComposer = new Hwc2::mock::Composer();
+        mFlinger.setupComposer(std::unique_ptr<Hwc2::Composer>(mComposer));
+
+        Mock::VerifyAndClear(mComposer);
+    }
+
+    // Mocks the behavior of applying a transaction from WMShell
+    void setGameModeMetadata(sp<Layer> layer, int gameMode) {
+        mLayerMetadata.setInt32(METADATA_GAME_MODE, gameMode);
+        layer->setMetadata(mLayerMetadata);
+        layer->setGameModeForTree(gameMode);
+    }
+
+    TestableSurfaceFlinger mFlinger;
+    Hwc2::mock::Composer* mComposer = nullptr;
+    client_cache_t mClientCache;
+    LayerMetadata mLayerMetadata;
+};
+
+TEST_F(GameModeTest, SetGameModeSetsForAllCurrentChildren) {
+    sp<BufferStateLayer> rootLayer = createBufferStateLayer();
+    sp<BufferStateLayer> childLayer1 = createBufferStateLayer();
+    sp<BufferStateLayer> childLayer2 = createBufferStateLayer();
+    rootLayer->addChild(childLayer1);
+    rootLayer->addChild(childLayer2);
+    rootLayer->setGameModeForTree(/*gameMode*/ 2);
+
+    EXPECT_EQ(rootLayer->getGameMode(), 2);
+    EXPECT_EQ(childLayer1->getGameMode(), 2);
+    EXPECT_EQ(childLayer2->getGameMode(), 2);
+}
+
+TEST_F(GameModeTest, AddChildAppliesGameModeFromParent) {
+    sp<BufferStateLayer> rootLayer = createBufferStateLayer();
+    sp<BufferStateLayer> childLayer = createBufferStateLayer();
+    rootLayer->setGameModeForTree(/*gameMode*/ 2);
+    rootLayer->addChild(childLayer);
+
+    EXPECT_EQ(rootLayer->getGameMode(), 2);
+    EXPECT_EQ(childLayer->getGameMode(), 2);
+}
+
+TEST_F(GameModeTest, RemoveChildResetsGameMode) {
+    sp<BufferStateLayer> rootLayer = createBufferStateLayer();
+    sp<BufferStateLayer> childLayer = createBufferStateLayer();
+    rootLayer->setGameModeForTree(/*gameMode*/ 2);
+    rootLayer->addChild(childLayer);
+
+    EXPECT_EQ(rootLayer->getGameMode(), 2);
+    EXPECT_EQ(childLayer->getGameMode(), 2);
+
+    rootLayer->removeChild(childLayer);
+    EXPECT_EQ(childLayer->getGameMode(), 0);
+}
+
+TEST_F(GameModeTest, ReparentingDoesNotOverrideMetadata) {
+    sp<BufferStateLayer> rootLayer = createBufferStateLayer();
+    sp<BufferStateLayer> childLayer1 = createBufferStateLayer();
+    sp<BufferStateLayer> childLayer2 = createBufferStateLayer();
+    rootLayer->setGameModeForTree(/*gameMode*/ 1);
+    rootLayer->addChild(childLayer1);
+
+    setGameModeMetadata(childLayer2, /*gameMode*/ 2);
+    rootLayer->addChild(childLayer2);
+
+    EXPECT_EQ(rootLayer->getGameMode(), 1);
+    EXPECT_EQ(childLayer1->getGameMode(), 1);
+    EXPECT_EQ(childLayer2->getGameMode(), 2);
+
+    rootLayer->removeChild(childLayer2);
+    EXPECT_EQ(childLayer2->getGameMode(), 2);
+}
+} // namespace android
\ No newline at end of file