diff --git a/services/surfaceflinger/tests/unittests/Android.bp b/services/surfaceflinger/tests/unittests/Android.bp
index 3c1b9d8..9f94c73 100644
--- a/services/surfaceflinger/tests/unittests/Android.bp
+++ b/services/surfaceflinger/tests/unittests/Android.bp
@@ -55,6 +55,7 @@
         "EventThreadTest.cpp",
         "FpsReporterTest.cpp",
         "FpsTest.cpp",
+        "FramebufferSurfaceTest.cpp",
         "FrameTimelineTest.cpp",
         "HWComposerTest.cpp",
         "OneShotTimerTest.cpp",
diff --git a/services/surfaceflinger/tests/unittests/FramebufferSurfaceTest.cpp b/services/surfaceflinger/tests/unittests/FramebufferSurfaceTest.cpp
new file mode 100644
index 0000000..b8df640
--- /dev/null
+++ b/services/surfaceflinger/tests/unittests/FramebufferSurfaceTest.cpp
@@ -0,0 +1,40 @@
+/*
+ * 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.
+ */
+
+#include "DisplayHardware/FramebufferSurface.h"
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+namespace android {
+
+class FramebufferSurfaceTest : public testing::Test {
+public:
+    ui::Size limitSize(const ui::Size& size, const ui::Size maxSize) {
+        return FramebufferSurface::limitSizeInternal(size, maxSize);
+    }
+};
+
+TEST_F(FramebufferSurfaceTest, limitSize) {
+    const ui::Size kMaxSize(1920, 1080);
+    EXPECT_EQ(ui::Size(1920, 1080), limitSize({3840, 2160}, kMaxSize));
+    EXPECT_EQ(ui::Size(1920, 1080), limitSize({1920, 1080}, kMaxSize));
+    EXPECT_EQ(ui::Size(1920, 1012), limitSize({4096, 2160}, kMaxSize));
+    EXPECT_EQ(ui::Size(1080, 1080), limitSize({3840, 3840}, kMaxSize));
+    EXPECT_EQ(ui::Size(1280, 720), limitSize({1280, 720}, kMaxSize));
+}
+
+} // namespace android