third_party/WebKit/Source/core/layout/PaginationTest.cpp

// Copyright 2015 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/layout/LayoutBlockFlow.h"
#include "core/layout/LayoutMultiColumnFlowThread.h"

#include "core/layout/LayoutTestHelper.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace blink {

class PaginationStrutTest : public RenderingTest {
 public:
  int StrutForBox(const char* block_id) {
    LayoutObject* layout_object = GetLayoutObjectByElementId(block_id);
    if (!layout_object || !layout_object->IsBox())
      return std::numeric_limits<int>::min();
    LayoutBox* box = ToLayoutBox(layout_object);
    return box->PaginationStrut().ToInt();
  }

  int StrutForLine(const char* container_id, int line_index) {
    LayoutObject* layout_object = GetLayoutObjectByElementId(container_id);
    if (!layout_object || !layout_object->IsLayoutBlockFlow())
      return std::numeric_limits<int>::min();
    LayoutBlockFlow* block = ToLayoutBlockFlow(layout_object);
    if (block->MultiColumnFlowThread())
      block = block->MultiColumnFlowThread();
    for (RootInlineBox *line = block->FirstRootBox(); line;
         line = line->NextRootBox(), line_index--) {
      if (line_index)
        continue;
      return line->PaginationStrut().ToInt();
    }
    return std::numeric_limits<int>::min();
  }
};

TEST_F(PaginationStrutTest, LineWithStrut) {
  SetBodyInnerHTML(
      "<div id='paged' style='overflow:-webkit-paged-y; height:200px; "
      "line-height:150px;'>"
      "    line1<br>"
      "    line2<br>"
      "</div>");
  EXPECT_EQ(0, StrutForLine("paged", 0));
  EXPECT_EQ(50, StrutForLine("paged", 1));
}

TEST_F(PaginationStrutTest, BlockWithStrut) {
  SetBodyInnerHTML(
      "<div style='overflow:-webkit-paged-y; height:200px; line-height:150px;'>"
      "    <div id='block1'>line1</div>"
      "    <div id='block2'>line2</div>"
      "</div>");
  EXPECT_EQ(0, StrutForBox("block1"));
  EXPECT_EQ(0, StrutForLine("block1", 0));
  EXPECT_EQ(50, StrutForBox("block2"));
  EXPECT_EQ(0, StrutForLine("block2", 0));
}

TEST_F(PaginationStrutTest, FloatWithStrut) {
  SetBodyInnerHTML(
      "<div style='overflow:-webkit-paged-y; height:200px; line-height:150px;'>"
      "    <div style='height:120px;'></div>"
      "    <div id='float' style='float:left;'>line</div>"
      "</div>");
  EXPECT_EQ(80, StrutForBox("float"));
  EXPECT_EQ(0, StrutForLine("float", 0));
}

TEST_F(PaginationStrutTest, UnbreakableBlockWithStrut) {
  SetBodyInnerHTML(
      "<style>img { display:block; width:100px; height:150px; outline:4px "
      "solid blue; padding:0; border:none; margin:0; }</style>"
      "<div style='overflow:-webkit-paged-y; height:200px;'>"
      "    <img id='img1'>"
      "    <img id='img2'>"
      "</div>");
  EXPECT_EQ(0, StrutForBox("img1"));
  EXPECT_EQ(50, StrutForBox("img2"));
}

TEST_F(PaginationStrutTest, BreakBefore) {
  SetBodyInnerHTML(
      "<div style='overflow:-webkit-paged-y; height:400px; line-height:50px;'>"
      "    <div id='block1'>line1</div>"
      "    <div id='block2' style='break-before:page;'>line2</div>"
      "</div>");
  EXPECT_EQ(0, StrutForBox("block1"));
  EXPECT_EQ(0, StrutForLine("block1", 0));
  EXPECT_EQ(350, StrutForBox("block2"));
  EXPECT_EQ(0, StrutForLine("block2", 0));
}

TEST_F(PaginationStrutTest, BlockWithStrutPropagatedFromInnerBlock) {
  SetBodyInnerHTML(
      "<div style='overflow:-webkit-paged-y; height:200px; line-height:150px;'>"
      "    <div id='block1'>line1</div>"
      "    <div id='block2' style='padding-top:2px;'>"
      "        <div id='innerBlock' style='padding-top:2px;'>line2</div>"
      "    </div>"
      "</div>");
  EXPECT_EQ(0, StrutForBox("block1"));
  EXPECT_EQ(0, StrutForLine("block1", 0));
  EXPECT_EQ(50, StrutForBox("block2"));
  EXPECT_EQ(0, StrutForBox("innerBlock"));
  EXPECT_EQ(0, StrutForLine("innerBlock", 0));
}

TEST_F(PaginationStrutTest, BlockWithStrutPropagatedFromUnbreakableInnerBlock) {
  SetBodyInnerHTML(
      "<div style='overflow:-webkit-paged-y; height:400px; line-height:150px;'>"
      "    <div id='block1'>line1</div>"
      "    <div id='block2' style='padding-top:2px;'>"
      "        <div id='innerBlock' style='padding-top:2px; "
      "break-inside:avoid;'>"
      "            line2<br>"
      "            line3<br>"
      "        </div>"
      "    </div>"
      "</div>");
  EXPECT_EQ(0, StrutForBox("block1"));
  EXPECT_EQ(0, StrutForLine("block1", 0));
  EXPECT_EQ(250, StrutForBox("block2"));
  EXPECT_EQ(0, StrutForBox("innerBlock"));
  EXPECT_EQ(0, StrutForLine("innerBlock", 0));
  EXPECT_EQ(0, StrutForLine("innerBlock", 1));
}

TEST_F(PaginationStrutTest, InnerBlockWithBreakBefore) {
  SetBodyInnerHTML(
      "<div style='overflow:-webkit-paged-y; height:200px; line-height:150px;'>"
      "    <div id='block1'>line1</div>"
      "    <div id='block2' style='padding-top:2px;'>"
      "        <div id='innerBlock' style='padding-top:2px; "
      "break-before:page;'>line2</div>"
      "    </div>"
      "</div>");
  EXPECT_EQ(0, StrutForBox("block1"));
  EXPECT_EQ(0, StrutForLine("block1", 0));
  // There's no class A break point before #innerBlock (they only exist
  // *between* siblings), so the break is propagated and applied before #block2.
  EXPECT_EQ(50, StrutForBox("block2"));
  EXPECT_EQ(0, StrutForBox("innerBlock"));
  EXPECT_EQ(0, StrutForLine("innerBlock", 0));
}

}  // namespace blink