Scale test

cc/tiles/tile_manager_unittest.cc

Index: cc/tiles/tile_manager_unittest.cc
diff --git a/cc/tiles/tile_manager_unittest.cc b/cc/tiles/tile_manager_unittest.cc
index 18013899a699594b4370b3fc9fffe323e81690c8..39b79c4dbb9efc6cda6358248350aba05cd33958 100644
--- a/cc/tiles/tile_manager_unittest.cc
+++ b/cc/tiles/tile_manager_unittest.cc
@@ -1960,5 +1960,38 @@ TEST_F(TileManagerTest, PartialRasterSuccessfullyDisabled) {
                         false /* partial_raster_enabled */);
 }
 
+#define PRECISION (15)
+void TestScale(float lw, float lh, float s) {
+  long slw = std::lround(lw * s);
+  long slh = std::lround(lh * s);
+
+  std::cout << "\nGiven Scale = " << std::setprecision(PRECISION) << s;
+  std::cout << "\nLayer Size = " << lw << " x " << lh;
+  std::cout << "\nScaled Layer Size = " << std::setprecision(PRECISION)
+            << (lw * s) << " x " << std::setprecision(PRECISION) << (lh * s);
+  std::cout << "\nRounded Scaled Layer Size = " << slw << " x " << slh;
+  std::cout << "\nApproximated Scale [sx, sy] = ["
+            << std::setprecision(PRECISION) << (slw / lw) << ", "
+            << std::setprecision(PRECISION) << (slh / lh) << "] <====";
+
+  std::cout << "\n\n";
+}
+
+TEST_F(TileManagerTest, ScaleTestSmallLayerSize) {
+  // Almost equal scales.
+  float scale1 = 7.33907556533813f;
+  float scale2 = 7.33907508850098f;
+  TestScale(501.f, 502.f, scale1);
+  TestScale(501.f, 502.f, scale2);
+}
+
+TEST_F(TileManagerTest, ScaleTestVeryBigLayerSize) {
+  // Almost equal scales.
+  float scale1 = 7.33907556533813f;
+  float scale2 = 7.33907508850098f;
+  TestScale(5010000.f, 5020000.f, scale1);
+  TestScale(5010000.f, 5020000.f, scale2);
+}
+
 }  // namespace
 }  // namespace cc