EditableTreeModel: Add a test

Add a test running QAbstractItemModelTester on the model.

Change-Id: I40c141c7e754ca05234da611534bd65e456be2fb
Reviewed-by: Kai Köhne <kai.koehne@qt.io>
(cherry picked from commit 283cdcd3d5fad368c9df1bcae69cbfbf9ade623f)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

examples/widgets/doc/src/editabletreemodel.qdoc

@@ -419,4 +419,19 @@
     \target TreeModel::data
     \target TreeModel::setupModelData
 
+    \section1 Testing the model
+
+    Correctly implementing an item model can be challenging. The class
+    \l QAbstractItemModelTester from the \l{Qt Test} module checks for model
+    consistency, like the model index creation and parent-child relationships.
+
+    You can test your model by just passing a model instance to the class
+    constructor, for instance as part of a Qt unit test:
+
+    \snippet itemviews/editabletreemodel/test.cpp 1
+
+    To create a test which can be run using the \c ctest executable,
+    \c add_test() is used:
+
+    \snippet itemviews/editabletreemodel/CMakeLists.txt 1
 */

examples/widgets/itemviews/editabletreemodel/CMakeLists.txt

@@ -10,7 +10,7 @@ endif()
 
 set(INSTALL_EXAMPLEDIR "${INSTALL_EXAMPLESDIR}/widgets/itemviews/editabletreemodel")
 
-find_package(Qt6 REQUIRED COMPONENTS Core Gui Widgets)
+find_package(Qt6 REQUIRED COMPONENTS Core Gui Test Widgets)
 
 qt_standard_project_setup()
 
@@ -49,3 +49,29 @@ install(TARGETS editabletreemodel
     BUNDLE DESTINATION "${INSTALL_EXAMPLEDIR}"
     LIBRARY DESTINATION "${INSTALL_EXAMPLEDIR}"
 )
+
+#! [1]
+# Unit Test
+
+include(CTest)
+
+qt_add_executable(editabletreemodel_tester
+    test.cpp
+    treeitem.cpp treeitem.h
+    treemodel.cpp treemodel.h)
+
+target_link_libraries(editabletreemodel_tester PRIVATE
+    Qt6::Core
+    Qt6::Test
+)
+
+qt_add_resources(editabletreemodel_tester "editabletreemodel"
+    PREFIX
+        "/"
+    FILES
+        ${editabletreemodel_resource_files}
+)
+
+add_test(NAME editabletreemodel_tester
+         COMMAND editabletreemodel_tester)
+#! [1]

examples/widgets/itemviews/editabletreemodel/test.cpp

@@ -0,0 +1,37 @@
+// Copyright (C) 2023 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#include "treemodel.h"
+
+#include <QAbstractItemModelTester>
+#include <QObject>
+#include <QTest>
+
+using namespace Qt::StringLiterals;
+
+//! [1]
+class TestEditableTreeModel : public QObject
+{
+    Q_OBJECT
+
+private slots:
+    void testTreeModel();
+};
+
+void TestEditableTreeModel::testTreeModel()
+{
+    constexpr auto fileName = ":/default.txt"_L1;
+    QFile file(fileName);
+    QVERIFY2(file.open(QIODevice::ReadOnly | QIODevice::Text),
+             qPrintable(fileName + " cannot be opened: "_L1 + file.errorString()));
+
+    const QStringList headers{"column1"_L1, "column2"_L1};
+    TreeModel model(headers, QString::fromUtf8(file.readAll()));
+
+    QAbstractItemModelTester tester(&model);
+}
+
+QTEST_APPLESS_MAIN(TestEditableTreeModel)
+
+#include "test.moc"
+//! [1]