feat(Storybook): reflect pages model changes in sections decorator model

Closes: #12216

storybook/pagesmodel.cpp

@@ -21,7 +21,7 @@ PagesModel::PagesModel(const QString &path, QObject *parent)
             this, &PagesModel::reload);
 }
 
-QList<PagesModelItem> PagesModel::load() {
+QList<PagesModelItem> PagesModel::load() const {
     static QRegularExpression fileNameRegex(
                 QRegularExpression::anchoredPattern("(.*)Page\\.qml"));
 
@@ -71,8 +71,8 @@ void PagesModel::readMetadata(QList<PagesModelItem> &items) {
 }
 
 void PagesModel::reload() {
-    QList<PagesModelItem> currentItems = load();
+    const QList<PagesModelItem> currentItems = load();
-    std::map<QString, PagesModelItem> mapping;
+    std::unordered_map<QString, PagesModelItem> mapping;
 
     for (const PagesModelItem &item : qAsConst(m_items))
         mapping[item.title] = item;
@@ -81,7 +81,7 @@ void PagesModel::reload() {
     std::vector<PagesModelItem> changedItems;
     std::vector<PagesModelItem> removedItems;
 
-    for (const PagesModelItem &item : qAsConst(currentItems)) {
+    for (const auto &item : currentItems) {
         auto it = mapping.find(item.title);
 
         if (it == mapping.end()) {
@@ -94,7 +94,7 @@ void PagesModel::reload() {
         }
     }
 
-    for (auto& [key, value] : mapping)
+    for (const auto& [key, value] : mapping)
         removedItems.push_back(value);
 
     for (auto& item : removedItems) {

storybook/pagesmodel.h

@@ -29,7 +29,7 @@ public:
 
     void reload();
 private:
-    QList<PagesModelItem> load();
+    QList<PagesModelItem> load() const;
 
     static void readMetadata(PagesModelItem &item);
     static void readMetadata(QList<PagesModelItem> &items);

storybook/sectionsdecoratormodel.cpp

@@ -23,10 +23,15 @@ void SectionsDecoratorModel::setSourceModel(QAbstractItemModel *sourceModel)
 
     initialize();
 
-    connect(sourceModel, &QAbstractItemModel::modelReset, this, &SectionsDecoratorModel::initialize);
+    connect(sourceModel, &QAbstractItemModel::modelReset, this,
-    connect(sourceModel, &QAbstractItemModel::rowsInserted, this, &SectionsDecoratorModel::initialize);
+            &SectionsDecoratorModel::initialize);
-    connect(sourceModel, &QAbstractItemModel::rowsRemoved, this, &SectionsDecoratorModel::initialize);
+    connect(sourceModel, &QAbstractItemModel::rowsMoved, this,
-    connect(sourceModel, &QAbstractItemModel::rowsMoved, this, &SectionsDecoratorModel::initialize);
+            &SectionsDecoratorModel::initialize);
+
+    connect(sourceModel, &QAbstractItemModel::rowsInserted, this,
+            &SectionsDecoratorModel::onInserted);
+    connect(sourceModel, &QAbstractItemModel::rowsRemoved, this,
+            &SectionsDecoratorModel::onRemoved);
 
     emit sourceModelChanged();
 }
@@ -160,3 +165,127 @@ void SectionsDecoratorModel::initialize()
 
     calculateOffsets();
 }
+
+void SectionsDecoratorModel::onInserted(const QModelIndex &parent,
+                                        int first, int last)
+{
+    if (first != last) {
+        initialize();
+        return;
+    }
+
+    const QVariant sectionVariant = m_sourceModel->data(
+                m_sourceModel->index(first, 0), m_sectionRole);
+    const QString section = sectionVariant.toString();
+
+    auto insertNewSection = [this, &section](int index) {
+        beginInsertRows(QModelIndex{}, index, index + 1);
+
+        m_rowsMetadata.insert(m_rowsMetadata.begin() + index, RowMetadata{});
+        m_rowsMetadata.insert(m_rowsMetadata.begin() + index,
+                              RowMetadata{ true, section, false, 0, 1});
+        calculateOffsets();
+        endInsertRows();
+    };
+
+    int itemsCounter = 0;
+    int sectionIndex = 0;
+
+    while (sectionIndex < m_rowsMetadata.size()) {
+        auto& sectionMetadata = m_rowsMetadata.at(sectionIndex);
+
+        if (sectionMetadata.sectionName == section) {
+            sectionMetadata.count++;
+
+            emit dataChanged(index(sectionIndex, 0), index(sectionIndex, 0),
+                             { Roles::SubitemsCountRole });
+
+            if (sectionMetadata.folded) {
+                // update folded section only
+                calculateOffsets();
+
+            } else {
+                // insert item into unfolded section
+                auto insertIndex = sectionIndex + (first - itemsCounter) + 1;
+
+                beginInsertRows(QModelIndex{}, insertIndex, insertIndex);
+                m_rowsMetadata.insert(m_rowsMetadata.begin() + insertIndex, RowMetadata{});
+                calculateOffsets();
+                endInsertRows();
+            }
+
+            break;
+        }
+
+        if (sectionMetadata.sectionName != section && itemsCounter == first) {
+            insertNewSection(sectionIndex);
+            break;
+        }
+
+        itemsCounter += sectionMetadata.count;
+        sectionIndex += 1 + (sectionMetadata.folded ? 0 : sectionMetadata.count);
+    }
+
+    if (sectionIndex == m_rowsMetadata.size())
+        insertNewSection(sectionIndex);
+}
+
+void SectionsDecoratorModel::onRemoved(const QModelIndex &parent,
+                                       int first, int last)
+{
+    if (first != last) {
+        initialize();
+        return;
+    }
+
+    int itemsCounter = 0;
+    int sectionIndex = 0;
+
+    while (sectionIndex < m_rowsMetadata.size()) {
+        auto& sectionMetadata = m_rowsMetadata.at(sectionIndex);
+
+        if (first < itemsCounter + sectionMetadata.count) {
+
+            if (sectionMetadata.folded) {
+                if (sectionMetadata.count == 1) {
+                    auto removeIndex = sectionIndex + (first - itemsCounter);
+                    beginRemoveRows(QModelIndex{}, removeIndex, removeIndex);
+                    m_rowsMetadata.erase(m_rowsMetadata.begin() + removeIndex,
+                                         m_rowsMetadata.begin() + removeIndex + 1);
+                    calculateOffsets();
+                    endRemoveRows();
+                } else {
+                    sectionMetadata.count--;
+                    calculateOffsets();
+
+                    emit dataChanged(index(sectionIndex, 0), index(sectionIndex, 0),
+                                     { Roles::SubitemsCountRole });
+                }
+            } else {
+                if (sectionMetadata.count == 1) {
+                    auto removeIndex = sectionIndex + (first - itemsCounter);
+                    beginRemoveRows(QModelIndex{}, removeIndex, removeIndex + 1);
+                    m_rowsMetadata.erase(m_rowsMetadata.begin() + removeIndex,
+                                         m_rowsMetadata.begin() + removeIndex + 2);
+                } else {
+                    sectionMetadata.count--;
+                    emit dataChanged(index(sectionIndex, 0), index(sectionIndex, 0),
+                                     { Roles::SubitemsCountRole });
+
+                    auto removeIndex = sectionIndex + (first - itemsCounter) + 1;
+
+                    beginRemoveRows(QModelIndex{}, removeIndex, removeIndex);
+                    m_rowsMetadata.erase(m_rowsMetadata.begin() + removeIndex);
+                }
+
+                calculateOffsets();
+                endRemoveRows();
+            }
+
+            break;
+        }
+
+        itemsCounter += sectionMetadata.count;
+        sectionIndex += 1 + (sectionMetadata.folded ? 0 : sectionMetadata.count);
+    }
+}

storybook/sectionsdecoratormodel.h

@@ -1,7 +1,6 @@
 #pragma once
 
 #include <QAbstractListModel>
-#include <optional>
 
 class SectionsDecoratorModel : public QAbstractListModel
 {
@@ -42,6 +41,9 @@ private:
     void initialize();
     void calculateOffsets();
 
+    void onInserted(const QModelIndex &parent, int first, int last);
+    void onRemoved(const QModelIndex &parent, int first, int last);
+
     QAbstractItemModel* m_sourceModel = nullptr;
     std::vector<RowMetadata> m_rowsMetadata;
     int m_sectionRole = 0;

storybook/tests/tst_SectionsDecoratorModel.cpp

@@ -13,6 +13,13 @@ class TestSourceModel : public QAbstractListModel {
 public:
     explicit TestSourceModel(QStringList categories)
         : m_categories(std::move(categories))
+    {
+        for (int i = 0; i < m_categories.size(); i++)
+            m_titles << QString("title %1").arg(i);
+    }
+
+    explicit TestSourceModel(QStringList categories, QStringList titles)
+        : m_categories(std::move(categories)), m_titles(std::move(titles))
     {
     }
 
@@ -27,11 +34,28 @@ public:
         if (!index.isValid())
             return {};
 
-        if (role == TitleRole) {
+        const auto row = index.row();
-            return QString("title %1").arg(index.row());
-        }
 
-        return m_categories.at(index.row());
+        if (role == TitleRole)
+            return m_titles.at(row);
+
+        return m_categories.at(row);
+    }
+
+    void insert(int index, QString category, QString title)
+    {
+        beginInsertRows(QModelIndex{}, index, index);
+        m_categories.insert(index, category);
+        m_titles.insert(index, title);
+        endInsertRows();
+    }
+
+    void remove(int index)
+    {
+        beginRemoveRows(QModelIndex{}, index, index);
+        m_categories.removeAt(index);
+        m_titles.removeAt(index);
+        endRemoveRows();
     }
 
     QHash<int, QByteArray> roleNames() const override {
@@ -42,6 +66,7 @@ public:
     }
 
     QStringList m_categories;
+    QStringList m_titles;
 };
 
 } // unnamed namespace
@@ -691,13 +716,9 @@ private slots:
         SectionsDecoratorModel model;
         model.setSourceModel(&proxy);
 
-        QSignalSpy spy(&model, &SectionsDecoratorModel::modelReset);
-
         proxy.setFilterRole(TestSourceModel::TitleRole);
         proxy.setFilterWildcard("*1");
 
-        QVERIFY(spy.count() > 1);
-
         QCOMPARE(model.rowCount(), 2);
         QCOMPARE(model.roleNames().count(), 6);
 
@@ -713,6 +734,810 @@ private slots:
         QCOMPARE(model.data(model.index(0, 0), SectionsDecoratorModel::SubitemsCountRole).toInt(), 1);
         QCOMPARE(model.data(model.index(1, 0), SectionsDecoratorModel::SubitemsCountRole).toInt(), 0);
     }
+
+    void insertionTest() {
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+            QSignalSpy insertionSpy(&model, &SectionsDecoratorModel::rowsInserted);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.insert(0, "Section 1", "New Title");
+            QCOMPARE(model.rowCount(), 10);
+            QCOMPARE(insertionSpy.count(), 1);
+            QCOMPARE(changeSpy.count(), 1);
+
+            auto insertionArguments = insertionSpy.takeFirst();
+            QCOMPARE(insertionArguments.at(1).toInt(), 1);
+            QCOMPARE(insertionArguments.at(2).toInt(), 1);
+
+            auto changeArguments = changeSpy.takeFirst();
+            QCOMPARE(changeArguments.at(0).toModelIndex(), model.index(0, 0));
+            QCOMPARE(changeArguments.at(1).toModelIndex(), model.index(0, 0));
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole).toString(), QString("New Title"));
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 1"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 2"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 3"));
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(6, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(7, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+            QCOMPARE(model.data(model.index(8, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(9, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+            QSignalSpy insertionSpy(&model, &SectionsDecoratorModel::rowsInserted);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.insert(1, "Section 1", "New Title");
+            QCOMPARE(model.rowCount(), 10);
+            QCOMPARE(insertionSpy.count(), 1);
+
+            auto insertionArguments = insertionSpy.takeFirst();
+            QCOMPARE(insertionArguments.at(1).toInt(), 2);
+            QCOMPARE(insertionArguments.at(2).toInt(), 2);
+
+            auto changeArguments = changeSpy.takeFirst();
+            QCOMPARE(changeArguments.at(0).toModelIndex(), model.index(0, 0));
+            QCOMPARE(changeArguments.at(1).toModelIndex(), model.index(0, 0));
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 1"));
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("New Title"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 2"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 3"));
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(6, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(7, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+            QCOMPARE(model.data(model.index(8, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(9, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+            QSignalSpy insertionSpy(&model, &SectionsDecoratorModel::rowsInserted);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.insert(2, "Section 1", "New Title");
+            QCOMPARE(model.rowCount(), 10);
+            QCOMPARE(insertionSpy.count(), 1);
+
+            auto insertionArguments = insertionSpy.takeFirst();
+            QCOMPARE(insertionArguments.at(1).toInt(), 3);
+            QCOMPARE(insertionArguments.at(2).toInt(), 3);
+
+            auto changeArguments = changeSpy.takeFirst();
+            QCOMPARE(changeArguments.at(0).toModelIndex(), model.index(0, 0));
+            QCOMPARE(changeArguments.at(1).toModelIndex(), model.index(0, 0));
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 1"));
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 2"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("New Title"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 3"));
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(6, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(7, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+            QCOMPARE(model.data(model.index(8, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(9, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+            QSignalSpy insertionSpy(&model, &SectionsDecoratorModel::rowsInserted);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.insert(3, "Section 1", "New Title");
+            QCOMPARE(model.rowCount(), 10);
+            QCOMPARE(insertionSpy.count(), 1);
+
+            auto insertionArguments = insertionSpy.takeFirst();
+            QCOMPARE(insertionArguments.at(1).toInt(), 4);
+            QCOMPARE(insertionArguments.at(2).toInt(), 4);
+
+            auto changeArguments = changeSpy.takeFirst();
+            QCOMPARE(changeArguments.at(0).toModelIndex(), model.index(0, 0));
+            QCOMPARE(changeArguments.at(1).toModelIndex(), model.index(0, 0));
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 1"));
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 2"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 3"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole).toString(), QString("New Title"));
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(6, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(7, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+            QCOMPARE(model.data(model.index(8, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(9, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+            QSignalSpy insertionSpy(&model, &SectionsDecoratorModel::rowsInserted);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.insert(3, "Section 2", "New Title");
+            QCOMPARE(model.rowCount(), 10);
+            QCOMPARE(insertionSpy.count(), 1);
+
+            auto insertionArguments = insertionSpy.takeFirst();
+            QCOMPARE(insertionArguments.at(1).toInt(), 5);
+            QCOMPARE(insertionArguments.at(2).toInt(), 5);
+
+            auto changeArguments = changeSpy.takeFirst();
+            QCOMPARE(changeArguments.at(0).toModelIndex(), model.index(4, 0));
+            QCOMPARE(changeArguments.at(1).toModelIndex(), model.index(4, 0));
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 1"));
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 2"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 3"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole).toString(), QString("New Title"));
+            QCOMPARE(model.data(model.index(6, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(7, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+            QCOMPARE(model.data(model.index(8, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(9, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+            QSignalSpy insertionSpy(&model, &SectionsDecoratorModel::rowsInserted);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.insert(4, "Section 2", "New Title");
+            QCOMPARE(model.rowCount(), 10);
+            QCOMPARE(insertionSpy.count(), 1);
+
+            auto insertionArguments = insertionSpy.takeFirst();
+            QCOMPARE(insertionArguments.at(1).toInt(), 6);
+            QCOMPARE(insertionArguments.at(2).toInt(), 6);
+
+            auto changeArguments = changeSpy.takeFirst();
+            QCOMPARE(changeArguments.at(0).toModelIndex(), model.index(4, 0));
+            QCOMPARE(changeArguments.at(1).toModelIndex(), model.index(4, 0));
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 1"));
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 2"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 3"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(6, 0), TestSourceModel::TitleRole).toString(), QString("New Title"));
+            QCOMPARE(model.data(model.index(7, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+            QCOMPARE(model.data(model.index(8, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(9, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+            QSignalSpy insertionSpy(&model, &SectionsDecoratorModel::rowsInserted);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.insert(5, "Section 3", "New Title");
+            QCOMPARE(model.rowCount(), 10);
+            QCOMPARE(insertionSpy.count(), 1);
+
+            auto insertionArguments = insertionSpy.takeFirst();
+            QCOMPARE(insertionArguments.at(1).toInt(), 8);
+            QCOMPARE(insertionArguments.at(2).toInt(), 8);
+
+            auto changeArguments = changeSpy.takeFirst();
+            QCOMPARE(changeArguments.at(0).toModelIndex(), model.index(7, 0));
+            QCOMPARE(changeArguments.at(1).toModelIndex(), model.index(7, 0));
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 1"));
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 2"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 3"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(6, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+            QCOMPARE(model.data(model.index(7, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(8, 0), TestSourceModel::TitleRole).toString(), QString("New Title"));
+            QCOMPARE(model.data(model.index(9, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+            QSignalSpy insertionSpy(&model, &SectionsDecoratorModel::rowsInserted);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.insert(6, "Section 3", "New Title");
+            QCOMPARE(model.rowCount(), 10);
+            QCOMPARE(insertionSpy.count(), 1);
+
+            auto insertionArguments = insertionSpy.takeFirst();
+            QCOMPARE(insertionArguments.at(1).toInt(), 9);
+            QCOMPARE(insertionArguments.at(2).toInt(), 9);
+
+            auto changeArguments = changeSpy.takeFirst();
+            QCOMPARE(changeArguments.at(0).toModelIndex(), model.index(7, 0));
+            QCOMPARE(changeArguments.at(1).toModelIndex(), model.index(7, 0));
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 1"));
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 2"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 3"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(6, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+            QCOMPARE(model.data(model.index(7, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(8, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+            QCOMPARE(model.data(model.index(9, 0), TestSourceModel::TitleRole).toString(), QString("New Title"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+
+            model.flipFolding(0);
+
+            QSignalSpy insertionSpy(&model, &SectionsDecoratorModel::rowsInserted);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.insert(0, "Section 1", "New Title");
+            QCOMPARE(model.rowCount(), 6);
+            QCOMPARE(insertionSpy.count(), 0);
+            QCOMPARE(changeSpy.count(), 1);
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+
+            model.flipFolding(0);
+
+            QSignalSpy insertionSpy(&model, &SectionsDecoratorModel::rowsInserted);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.insert(1, "Section 1", "New Title");
+            QCOMPARE(model.rowCount(), 6);
+            QCOMPARE(insertionSpy.count(), 0);
+            QCOMPARE(changeSpy.count(), 1);
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+
+            model.flipFolding(0);
+
+            QSignalSpy insertionSpy(&model, &SectionsDecoratorModel::rowsInserted);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.insert(3, "Section 1", "New Title");
+            QCOMPARE(model.rowCount(), 6);
+            QCOMPARE(insertionSpy.count(), 0);
+            QCOMPARE(changeSpy.count(), 1);
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+
+            model.flipFolding(0);
+
+            QSignalSpy insertionSpy(&model, &SectionsDecoratorModel::rowsInserted);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.insert(3, "Section 2", "New Title");
+            QCOMPARE(model.rowCount(), 7);
+            QCOMPARE(insertionSpy.count(), 1);
+
+            QCOMPARE(changeSpy.count(), 1);
+
+            auto changeArguments = changeSpy.takeFirst();
+            QCOMPARE(changeArguments.at(0).toModelIndex(), model.index(1, 0));
+            QCOMPARE(changeArguments.at(1).toModelIndex(), model.index(1, 0));
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("New Title"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(6, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+
+            model.flipFolding(0);
+
+            QSignalSpy insertionSpy(&model, &SectionsDecoratorModel::rowsInserted);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.insert(4, "Section 2", "New Title");
+            QCOMPARE(model.rowCount(), 7);
+            QCOMPARE(insertionSpy.count(), 1);
+            QCOMPARE(changeSpy.count(), 1);
+
+            auto changeArguments = changeSpy.takeFirst();
+            QCOMPARE(changeArguments.at(0).toModelIndex(), model.index(1, 0));
+            QCOMPARE(changeArguments.at(1).toModelIndex(), model.index(1, 0));
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("New Title"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(6, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+            QSignalSpy insertionSpy(&model, &SectionsDecoratorModel::rowsInserted);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.insert(0, "Section 0", "New Title");
+            QCOMPARE(model.rowCount(), 11);
+            QCOMPARE(insertionSpy.count(), 1);
+            QCOMPARE(changeSpy.count(), 0);
+
+            auto arguments = insertionSpy.takeFirst();
+            QCOMPARE(arguments.at(1).toInt(), 0);
+            QCOMPARE(arguments.at(2).toInt(), 1);
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole).toString(), QString("New Title"));
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 1"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 2"));
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 3"));
+            QCOMPARE(model.data(model.index(6, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(7, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(8, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+            QCOMPARE(model.data(model.index(9, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(10, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+            QSignalSpy insertionSpy(&model, &SectionsDecoratorModel::rowsInserted);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.insert(3, "Section 0", "New Title");
+            QCOMPARE(model.rowCount(), 11);
+            QCOMPARE(insertionSpy.count(), 1);
+            QCOMPARE(changeSpy.count(), 0);
+
+            auto arguments = insertionSpy.takeFirst();
+            QCOMPARE(arguments.at(1).toInt(), 4);
+            QCOMPARE(arguments.at(2).toInt(), 5);
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 1"));
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 2"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 3"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole).toString(), QString("New Title"));
+            QCOMPARE(model.data(model.index(6, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(7, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(8, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+            QCOMPARE(model.data(model.index(9, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(10, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+            QSignalSpy insertionSpy(&model, &SectionsDecoratorModel::rowsInserted);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.insert(6, "Section 0", "New Title");
+            QCOMPARE(model.rowCount(), 11);
+            QCOMPARE(insertionSpy.count(), 1);
+            QCOMPARE(changeSpy.count(), 0);
+
+            auto arguments = insertionSpy.takeFirst();
+            QCOMPARE(arguments.at(1).toInt(), 9);
+            QCOMPARE(arguments.at(2).toInt(), 10);
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 1"));
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 2"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 3"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(6, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+            QCOMPARE(model.data(model.index(7, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(8, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+            QCOMPARE(model.data(model.index(9, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(10, 0), TestSourceModel::TitleRole).toString(), QString("New Title"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+            model.flipFolding(4);
+
+            QSignalSpy insertionSpy(&model, &SectionsDecoratorModel::rowsInserted);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.insert(6, "Section 0", "New Title");
+            QCOMPARE(model.rowCount(), 9);
+            QCOMPARE(insertionSpy.count(), 1);
+            QCOMPARE(changeSpy.count(), 0);
+
+            auto arguments = insertionSpy.takeFirst();
+            QCOMPARE(arguments.at(1).toInt(), 7);
+            QCOMPARE(arguments.at(2).toInt(), 8);
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 1"));
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 2"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 3"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(6, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+            QCOMPARE(model.data(model.index(7, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(8, 0), TestSourceModel::TitleRole).toString(), QString("New Title"));
+        }
+    }
+
+    void removalTest() {
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+            QSignalSpy removalSpy(&model, &SectionsDecoratorModel::rowsRemoved);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.remove(0);
+            QCOMPARE(model.rowCount(), 8);
+            QCOMPARE(removalSpy.count(), 1);
+            QCOMPARE(changeSpy.count(), 1);
+
+            auto removalArguments = removalSpy.takeFirst();
+            QCOMPARE(removalArguments.at(1).toInt(), 1);
+            QCOMPARE(removalArguments.at(2).toInt(), 1);
+
+            auto changeArguments = changeSpy.takeFirst();
+            QCOMPARE(changeArguments.at(0).toModelIndex(), model.index(0, 0));
+            QCOMPARE(changeArguments.at(1).toModelIndex(), model.index(0, 0));
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 2"));
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 3"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+            QCOMPARE(model.data(model.index(6, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(7, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+            QSignalSpy removalSpy(&model, &SectionsDecoratorModel::rowsRemoved);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.remove(1);
+            QCOMPARE(model.rowCount(), 8);
+            QCOMPARE(removalSpy.count(), 1);
+            QCOMPARE(changeSpy.count(), 1);
+
+            auto removalArguments = removalSpy.takeFirst();
+            QCOMPARE(removalArguments.at(1).toInt(), 2);
+            QCOMPARE(removalArguments.at(2).toInt(), 2);
+
+            auto changeArguments = changeSpy.takeFirst();
+            QCOMPARE(changeArguments.at(0).toModelIndex(), model.index(0, 0));
+            QCOMPARE(changeArguments.at(1).toModelIndex(), model.index(0, 0));
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 1"));
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 3"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+            QCOMPARE(model.data(model.index(6, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(7, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+            QSignalSpy removalSpy(&model, &SectionsDecoratorModel::rowsRemoved);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.remove(2);
+            QCOMPARE(model.rowCount(), 8);
+            QCOMPARE(removalSpy.count(), 1);
+            QCOMPARE(changeSpy.count(), 1);
+
+            auto removalArguments = removalSpy.takeFirst();
+            QCOMPARE(removalArguments.at(1).toInt(), 3);
+            QCOMPARE(removalArguments.at(2).toInt(), 3);
+
+            auto changeArguments = changeSpy.takeFirst();
+            QCOMPARE(changeArguments.at(0).toModelIndex(), model.index(0, 0));
+            QCOMPARE(changeArguments.at(1).toModelIndex(), model.index(0, 0));
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 1"));
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 2"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+            QCOMPARE(model.data(model.index(6, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(7, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+            QSignalSpy removalSpy(&model, &SectionsDecoratorModel::rowsRemoved);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.remove(5);
+            QCOMPARE(model.rowCount(), 7);
+            QCOMPARE(removalSpy.count(), 1);
+            QCOMPARE(changeSpy.count(), 0);
+
+            auto removalArguments = removalSpy.takeFirst();
+            QCOMPARE(removalArguments.at(1).toInt(), 7);
+            QCOMPARE(removalArguments.at(2).toInt(), 8);
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 1"));
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 2"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 3"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(6, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+            QSignalSpy removalSpy(&model, &SectionsDecoratorModel::rowsRemoved);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.remove(3);
+            QCOMPARE(model.rowCount(), 6);
+            QCOMPARE(removalSpy.count(), 1);
+            QCOMPARE(changeSpy.count(), 0);
+
+            auto arguments = removalSpy.takeFirst();
+            QCOMPARE(arguments.at(1).toInt(), 4);
+            QCOMPARE(arguments.at(2).toInt(), 5);
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 1"));
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 2"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 3"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+        }
+        {
+            TestSourceModel src(QStringList{"Section 1"}, QStringList{"Title__ 1"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+
+            QSignalSpy removalSpy(&model, &SectionsDecoratorModel::rowsRemoved);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.remove(0);
+            QCOMPARE(model.rowCount(), 0);
+            QCOMPARE(removalSpy.count(), 1);
+            QCOMPARE(changeSpy.count(), 0);
+
+            auto arguments = removalSpy.takeFirst();
+            QCOMPARE(arguments.at(1).toInt(), 0);
+            QCOMPARE(arguments.at(2).toInt(), 1);
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+            model.flipFolding(0);
+
+            QSignalSpy removalSpy(&model, &SectionsDecoratorModel::rowsRemoved);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.remove(0);
+            QCOMPARE(model.rowCount(), 6);
+            QCOMPARE(removalSpy.count(), 0);
+            QCOMPARE(changeSpy.count(), 1);
+
+            auto changeArguments = changeSpy.takeFirst();
+            QCOMPARE(changeArguments.at(0).toModelIndex(), model.index(0, 0));
+            QCOMPARE(changeArguments.at(1).toModelIndex(), model.index(0, 0));
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 6"));
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+            model.flipFolding(0);
+            model.flipFolding(1);
+            model.flipFolding(2);
+
+            QSignalSpy removalSpy(&model, &SectionsDecoratorModel::rowsRemoved);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.remove(1);
+            QCOMPARE(model.rowCount(), 3);
+            QCOMPARE(removalSpy.count(), 0);
+            QCOMPARE(changeSpy.count(), 1);
+
+            auto changeArguments = changeSpy.takeFirst();
+            QCOMPARE(changeArguments.at(0).toModelIndex(), model.index(0, 0));
+            QCOMPARE(changeArguments.at(1).toModelIndex(), model.index(0, 0));
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole), QVariant{});
+        }
+        {
+            TestSourceModel src(
+                        QStringList{"Section 1", "Section 1", "Section 1", "Section 2", "Section 2", "Section 3"},
+                        QStringList{"Title__ 1", "Title__ 2", "Title__ 3", "Title__ 4", "Title__ 5", "Title__ 6"});
+
+            SectionsDecoratorModel model;
+            model.setSourceModel(&src);
+            model.flipFolding(7);
+
+            QSignalSpy removalSpy(&model, &SectionsDecoratorModel::rowsRemoved);
+            QSignalSpy changeSpy(&model, &SectionsDecoratorModel::dataChanged);
+
+            src.remove(5);
+            QCOMPARE(model.rowCount(), 7);
+            QCOMPARE(removalSpy.count(), 1);
+            QCOMPARE(changeSpy.count(), 0);
+
+            auto removalArguments = removalSpy.takeFirst();
+            QCOMPARE(removalArguments.at(1).toInt(), 7);
+            QCOMPARE(removalArguments.at(2).toInt(), 7);
+
+            QCOMPARE(model.data(model.index(0, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(1, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 1"));
+            QCOMPARE(model.data(model.index(2, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 2"));
+            QCOMPARE(model.data(model.index(3, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 3"));
+            QCOMPARE(model.data(model.index(4, 0), TestSourceModel::TitleRole), QVariant{});
+            QCOMPARE(model.data(model.index(5, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 4"));
+            QCOMPARE(model.data(model.index(6, 0), TestSourceModel::TitleRole).toString(), QString("Title__ 5"));
+        }
+    }
 };
 
 // TODO: signals emission testing using QSignalSpy