diff -r 000000000000 -r 6474c204b198 gfx/tests/gtest/TestTiledLayerBuffer.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/tests/gtest/TestTiledLayerBuffer.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,78 @@
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+#include "TiledLayerBuffer.h"
+
+#include "gtest/gtest.h"
+
+namespace mozilla {
+namespace layers {
+
+struct TestTiledLayerTile {
+  int value;
+  TestTiledLayerTile(int v = 0) {
+    value = v;
+  }
+  bool operator== (const TestTiledLayerTile& o) const {
+    return value == o.value;
+  }
+  bool operator!= (const TestTiledLayerTile& o) const {
+    return value != o.value;
+  }
+};
+
+class TestTiledLayerBuffer : public TiledLayerBuffer<TestTiledLayerBuffer, TestTiledLayerTile>
+{
+  friend class TiledLayerBuffer<TestTiledLayerBuffer, TestTiledLayerTile>;
+
+public:
+  TestTiledLayerTile GetPlaceholderTile() const {
+    return TestTiledLayerTile(-1);
+  }
+
+  TestTiledLayerTile ValidateTile(TestTiledLayerTile aTile, const nsIntPoint& aTileOrigin, const nsIntRegion& aDirtyRect) {
+    return TestTiledLayerTile();
+  }
+
+  void ReleaseTile(TestTiledLayerTile aTile)
+  {
+
+  }
+
+  void SwapTiles(TestTiledLayerTile& aTileA, TestTiledLayerTile& aTileB)
+  {
+    TestTiledLayerTile oldTileA = aTileA;
+    aTileA = aTileB;
+    aTileB = oldTileA;
+  }
+
+  void TestUpdate(const nsIntRegion& aNewValidRegion, const nsIntRegion& aPaintRegion)
+  {
+    Update(aNewValidRegion, aPaintRegion);
+  }
+};
+
+TEST(TiledLayerBuffer, TileConstructor) {
+  TestTiledLayerBuffer buffer;
+}
+
+TEST(TiledLayerBuffer, TileStart) {
+  TestTiledLayerBuffer buffer;
+
+  ASSERT_EQ(buffer.RoundDownToTileEdge(10, 256), 0);
+  ASSERT_EQ(buffer.RoundDownToTileEdge(-10, 256), -256);
+}
+
+TEST(TiledLayerBuffer, EmptyUpdate) {
+  TestTiledLayerBuffer buffer;
+
+  nsIntRegion validRegion(nsIntRect(0, 0, 10, 10));
+  buffer.TestUpdate(validRegion, validRegion);
+
+  ASSERT_EQ(buffer.GetValidRegion(), validRegion);
+}
+
+}
+}