diff --git a/services/surfaceflinger/tests/unittests/Android.bp b/services/surfaceflinger/tests/unittests/Android.bp
index 12b41fd..d4eac88 100644
--- a/services/surfaceflinger/tests/unittests/Android.bp
+++ b/services/surfaceflinger/tests/unittests/Android.bp
@@ -49,6 +49,7 @@
         "SchedulerUtilsTest.cpp",
         "RefreshRateConfigsTest.cpp",
         "RefreshRateStatsTest.cpp",
+        "RegionSamplingTest.cpp",
         "TimeStatsTest.cpp",
         "mock/DisplayHardware/MockComposer.cpp",
         "mock/DisplayHardware/MockDisplay.cpp",
diff --git a/services/surfaceflinger/tests/unittests/RegionSamplingTest.cpp b/services/surfaceflinger/tests/unittests/RegionSamplingTest.cpp
new file mode 100644
index 0000000..51d6d7e
--- /dev/null
+++ b/services/surfaceflinger/tests/unittests/RegionSamplingTest.cpp
@@ -0,0 +1,77 @@
+/*
+ * Copyright 2019 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 "RegionSamplingTest"
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include <array>
+#include <limits>
+
+#include "RegionSamplingThread.h"
+
+namespace android {
+
+struct RegionSamplingTest : testing::Test {
+public:
+    static uint32_t constexpr kBlack = 0;
+    static uint32_t constexpr kWhite = std::numeric_limits<uint32_t>::max();
+    static int constexpr kWidth = 98;
+    static int constexpr kStride = 100;
+    static int constexpr kHeight = 29;
+    std::array<uint32_t, kHeight * kStride> buffer;
+    Rect const whole_area{0, 0, kWidth, kHeight};
+};
+
+TEST_F(RegionSamplingTest, calculate_mean_white) {
+    std::fill(buffer.begin(), buffer.end(), kWhite);
+    EXPECT_THAT(sampleArea(buffer.data(), kStride, whole_area), testing::FloatEq(1.0f));
+}
+
+TEST_F(RegionSamplingTest, calculate_mean_black) {
+    std::fill(buffer.begin(), buffer.end(), kBlack);
+    EXPECT_THAT(sampleArea(buffer.data(), kStride, whole_area), testing::FloatEq(0.0f));
+}
+
+TEST_F(RegionSamplingTest, calculate_mean_partial_region) {
+    auto const halfway_down = kHeight >> 1;
+    auto const half = halfway_down * kStride;
+    Rect const partial_region = {whole_area.left, whole_area.top, whole_area.right,
+                                 whole_area.top + halfway_down};
+    std::fill(buffer.begin(), buffer.begin() + half, 0);
+    std::fill(buffer.begin() + half, buffer.end(), kWhite);
+    EXPECT_THAT(sampleArea(buffer.data(), kStride, partial_region), testing::FloatEq(0.0f));
+}
+
+TEST_F(RegionSamplingTest, calculate_mean_mixed_values) {
+    std::generate(buffer.begin(), buffer.end(), [n = 0]() mutable {
+        uint32_t const pixel = (n % std::numeric_limits<uint8_t>::max()) << ((n % 3) * CHAR_BIT);
+        n++;
+        return pixel;
+    });
+    EXPECT_THAT(sampleArea(buffer.data(), kStride, whole_area), testing::FloatNear(0.083f, 0.01f));
+}
+
+TEST_F(RegionSamplingTest, bimodal_tiebreaker) {
+    std::generate(buffer.begin(), buffer.end(),
+                  [n = 0]() mutable { return (n++ % 2) ? kBlack : kWhite; });
+    // presently there's no tiebreaking strategy in place, accept either of the means
+    EXPECT_THAT(sampleArea(buffer.data(), kStride, whole_area),
+                testing::AnyOf(testing::FloatEq(1.0), testing::FloatEq(0.0f)));
+}
+
+} // namespace android