Support subpixel layout for borders.

third_party/WebKit/Source/core/style/BorderValueTest.cpp

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/style/BorderValue.h"
+
+#include <limits.h>
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace blink {
+
+TEST(BorderValueTest, BorderValueWidth) {
+  const float tolerance = 1.0f / kBorderWidthDenominator;
+  BorderValue border;
+
+  border.setWidth(1.0f);
+  EXPECT_FLOAT_EQ(1.0f, border.width());
+  border.setWidth(1.25f);
+  EXPECT_FLOAT_EQ(1.25f, border.width());
+  border.setWidth(1.1f);
+  EXPECT_NEAR(border.width(), 1.1f, tolerance);
+  border.setWidth(1.33f);
+  EXPECT_NEAR(border.width(), 1.33f, tolerance);
+  border.setWidth(1.3333f);
+  EXPECT_NEAR(border.width(), 1.3333f, tolerance);
+  border.setWidth(1.53434f);
+  EXPECT_NEAR(border.width(), 1.53434f, tolerance);
+  border.setWidth(345634);
+  EXPECT_NEAR(border.width(), 345634.0f, tolerance);
+  border.setWidth(345634.12335f);
+  EXPECT_NEAR(border.width(), 345634.12335f, tolerance);
+
+  border.setWidth(0);
+  EXPECT_EQ(0, border.width());
+  border.setWidth(1);
+  EXPECT_EQ(1, border.width());
+  border.setWidth(100);
+  EXPECT_EQ(100, border.width());
+  border.setWidth(1000);
+  EXPECT_EQ(1000, border.width());
+  border.setWidth(10000);
+  EXPECT_EQ(10000, border.width());
+  border.setWidth(kMaxForBorderWidth / 2);
+  EXPECT_EQ(kMaxForBorderWidth / 2, border.width());
+  border.setWidth(kMaxForBorderWidth - 1);
+  EXPECT_EQ(kMaxForBorderWidth - 1, border.width());
+  border.setWidth(kMaxForBorderWidth);
+  EXPECT_EQ(kMaxForBorderWidth, border.width());
+  border.setWidth(kMaxForBorderWidth + 1);
+  EXPECT_EQ(kMaxForBorderWidth, border.width());
+  border.setWidth(INT_MAX / 2);
+  EXPECT_EQ(kMaxForBorderWidth, border.width());
+  border.setWidth(INT_MAX);
+  EXPECT_EQ(kMaxForBorderWidth, border.width());
+}
+
+}  // namespace blink