diff -r 000000000000 -r 6474c204b198 gfx/2d/unittest/TestPoint.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/2d/unittest/TestPoint.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,46 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "TestPoint.h"
+
+#include "Point.h"
+
+using namespace mozilla::gfx;
+
+TestPoint::TestPoint()
+{
+  REGISTER_TEST(TestPoint, Addition);
+  REGISTER_TEST(TestPoint, Subtraction);
+}
+
+void
+TestPoint::Addition()
+{
+  Point a, b;
+  a.x = 2;
+  a.y = 2;
+  b.x = 5;
+  b.y = -5;
+
+  a += b;
+
+  VERIFY(a.x == 7);
+  VERIFY(a.y == -3);
+}
+
+void
+TestPoint::Subtraction()
+{
+  Point a, b;
+  a.x = 2;
+  a.y = 2;
+  b.x = 5;
+  b.y = -5;
+
+  a -= b;
+
+  VERIFY(a.x == -3);
+  VERIFY(a.y == 7);
+}