diff --git a/webrtc/modules/desktop_capture/BUILD.gn b/webrtc/modules/desktop_capture/BUILD.gn
index 5854b3438a..93ceb752c2 100644
--- a/webrtc/modules/desktop_capture/BUILD.gn
+++ b/webrtc/modules/desktop_capture/BUILD.gn
@@ -76,6 +76,7 @@ if (rtc_include_tests) {
       "desktop_and_cursor_composer_unittest.cc",
       "desktop_capturer_differ_wrapper_unittest.cc",
       "desktop_frame_rotation_unittest.cc",
+      "desktop_geometry_unittest.cc",
       "desktop_region_unittest.cc",
       "differ_block_unittest.cc",
       "fallback_desktop_capturer_wrapper_unittest.cc",
diff --git a/webrtc/modules/desktop_capture/desktop_geometry_unittest.cc b/webrtc/modules/desktop_capture/desktop_geometry_unittest.cc
new file mode 100644
index 0000000000..0628d9aeb2
--- /dev/null
+++ b/webrtc/modules/desktop_capture/desktop_geometry_unittest.cc
@@ -0,0 +1,69 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/desktop_capture/desktop_geometry.h"
+
+#include "webrtc/test/gtest.h"
+
+namespace webrtc {
+
+TEST(DesktopRectTest, UnionBetweenTwoNonEmptyRects) {
+  DesktopRect rect = DesktopRect::MakeLTRB(1, 1, 2, 2);
+  rect.UnionWith(DesktopRect::MakeLTRB(-2, -2, -1, -1));
+  ASSERT_TRUE(rect.equals(DesktopRect::MakeLTRB(-2, -2, 2, 2)));
+}
+
+TEST(DesktopRectTest, UnionWithEmptyRect) {
+  DesktopRect rect = DesktopRect::MakeWH(1, 1);
+  rect.UnionWith(DesktopRect());
+  ASSERT_TRUE(rect.equals(DesktopRect::MakeWH(1, 1)));
+
+  rect = DesktopRect::MakeXYWH(1, 1, 2, 2);
+  rect.UnionWith(DesktopRect());
+  ASSERT_TRUE(rect.equals(DesktopRect::MakeXYWH(1, 1, 2, 2)));
+
+  rect = DesktopRect::MakeXYWH(1, 1, 2, 2);
+  rect.UnionWith(DesktopRect::MakeXYWH(3, 3, 0, 0));
+  ASSERT_TRUE(rect.equals(DesktopRect::MakeXYWH(1, 1, 2, 2)));
+}
+
+TEST(DesktopRectTest, EmptyRectUnionWithNonEmptyOne) {
+  DesktopRect rect;
+  rect.UnionWith(DesktopRect::MakeWH(1, 1));
+  ASSERT_TRUE(rect.equals(DesktopRect::MakeWH(1, 1)));
+
+  rect = DesktopRect();
+  rect.UnionWith(DesktopRect::MakeXYWH(1, 1, 2, 2));
+  ASSERT_TRUE(rect.equals(DesktopRect::MakeXYWH(1, 1, 2, 2)));
+
+  rect = DesktopRect::MakeXYWH(3, 3, 0, 0);
+  rect.UnionWith(DesktopRect::MakeXYWH(1, 1, 2, 2));
+  ASSERT_TRUE(rect.equals(DesktopRect::MakeXYWH(1, 1, 2, 2)));
+}
+
+TEST(DesktopRectTest, EmptyRectUnionWithEmptyOne) {
+  DesktopRect rect;
+  rect.UnionWith(DesktopRect());
+  ASSERT_TRUE(rect.is_empty());
+
+  rect = DesktopRect::MakeXYWH(1, 1, 0, 0);
+  rect.UnionWith(DesktopRect());
+  ASSERT_TRUE(rect.is_empty());
+
+  rect = DesktopRect();
+  rect.UnionWith(DesktopRect::MakeXYWH(1, 1, 0, 0));
+  ASSERT_TRUE(rect.is_empty());
+
+  rect = DesktopRect::MakeXYWH(1, 1, 0, 0);
+  rect.UnionWith(DesktopRect::MakeXYWH(-1, -1, 0, 0));
+  ASSERT_TRUE(rect.is_empty());
+}
+
+}  // namespace webrtc