[New Multicolumn] Preparatory work for nested multicol support.

Source/core/layout/MultiColumnFragmentainerGroupTest.cpp

Index: Source/core/layout/MultiColumnFragmentainerGroupTest.cpp
diff --git a/Source/core/layout/MultiColumnFragmentainerGroupTest.cpp b/Source/core/layout/MultiColumnFragmentainerGroupTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..34c7ce6231650cdc6bcfe466e71f5cc7811fde46
--- /dev/null
+++ b/Source/core/layout/MultiColumnFragmentainerGroupTest.cpp
@@ -0,0 +1,107 @@
+// 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 "config.h"
+
+#include "core/layout/MultiColumnFragmentainerGroup.h"
+
+#include "core/rendering/RenderMultiColumnFlowThread.h"
+#include "core/rendering/RenderMultiColumnSet.h"
+#include "core/rendering/RenderingTestHelper.h"
+
+#include <gtest/gtest.h>
+
+namespace blink {
+
+namespace {
+
+class MultiColumnFragmentainerGroupTest : public RenderingTest {
+public:
+    MultiColumnFragmentainerGroupTest() : m_flowThread(0), m_columnSet(0) { }
+
+protected:
+    virtual void SetUp() override;
+    virtual void TearDown() override;
+
+    RenderMultiColumnSet& columnSet() { return *m_columnSet; }
+
+    static int groupCount(const MultiColumnFragmentainerGroupList&);
+
+private:
+    RenderMultiColumnFlowThread* m_flowThread;
+    RenderMultiColumnSet* m_columnSet;
+};
+
+void MultiColumnFragmentainerGroupTest::SetUp()
+{
+    RenderingTest::SetUp();
+    RefPtr<LayoutStyle> style = LayoutStyle::create();
+    m_flowThread = RenderMultiColumnFlowThread::createAnonymous(document(), *style.get());
+    m_columnSet = RenderMultiColumnSet::createAnonymous(*m_flowThread, *m_flowThread->style());
+}
+
+void MultiColumnFragmentainerGroupTest::TearDown()
+{
+    m_columnSet->destroy();
+    m_flowThread->destroy();
+    RenderingTest::TearDown();
+}
+
+int MultiColumnFragmentainerGroupTest::groupCount(const MultiColumnFragmentainerGroupList& groupList)
+{
+    int count = 0;
+    for (const auto& dummyGroup : groupList) {
+        (void) dummyGroup;
+        count++;
+    }
+    return count;
+}
+
+TEST_F(MultiColumnFragmentainerGroupTest, Create)
+{
+    MultiColumnFragmentainerGroupList groupList(columnSet());
+    EXPECT_EQ(groupCount(groupList), 1);
+}
+
+TEST_F(MultiColumnFragmentainerGroupTest, DeleteExtra)
+{
+    MultiColumnFragmentainerGroupList groupList(columnSet());
+    EXPECT_EQ(groupCount(groupList), 1);
+    groupList.deleteExtraGroups();
+    EXPECT_EQ(groupCount(groupList), 1);
+}
+
+TEST_F(MultiColumnFragmentainerGroupTest, AddThenDeleteExtra)
+{
+    MultiColumnFragmentainerGroupList groupList(columnSet());
+    EXPECT_EQ(groupCount(groupList), 1);
+    groupList.addExtraGroup();
+    EXPECT_EQ(groupCount(groupList), 2);
+    groupList.deleteExtraGroups();
+    EXPECT_EQ(groupCount(groupList), 1);
+}
+
+TEST_F(MultiColumnFragmentainerGroupTest, AddTwoThenDeleteExtraThenAddThreeThenDeleteExtra)
+{
+    MultiColumnFragmentainerGroupList groupList(columnSet());
+    EXPECT_EQ(groupCount(groupList), 1);
+    groupList.addExtraGroup();
+    EXPECT_EQ(groupCount(groupList), 2);
+    groupList.addExtraGroup();
+    EXPECT_EQ(groupCount(groupList), 3);
+    groupList.deleteExtraGroups();
+    EXPECT_EQ(groupCount(groupList), 1);
+    groupList.addExtraGroup();
+    EXPECT_EQ(groupCount(groupList), 2);
+    groupList.addExtraGroup();
+    EXPECT_EQ(groupCount(groupList), 3);
+    groupList.addExtraGroup();
+    EXPECT_EQ(groupCount(groupList), 4);
+    groupList.deleteExtraGroups();
+    EXPECT_EQ(groupCount(groupList), 1);
+}
+
+} // anonymous namespace
+
+} // blink