Tooling: Add QML preview debug service

Task-number: QDS-181
Change-Id: I02193afb84aa111792d8bebff3bdd9b410f9db5a
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

8 files changed, 614 insertions, 0 deletions

diff --git a/tests/auto/qml/debugger/qqmlpreview/data/broken.qml b/tests/auto/qml/debugger/qqmlpreview/data/broken.qml
new file mode 100644
index 0000000000..4ebbf7576a
--- /dev/null
+++ b/tests/auto/qml/debugger/qqmlpreview/data/broken.qml
@@ -0,0 +1,31 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.0
+
+Item {
diff --git a/tests/auto/qml/debugger/qqmlpreview/data/qtquick2.qml b/tests/auto/qml/debugger/qqmlpreview/data/qtquick2.qml
new file mode 100644
index 0000000000..b525ab4fa0
--- /dev/null
+++ b/tests/auto/qml/debugger/qqmlpreview/data/qtquick2.qml
@@ -0,0 +1,71 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.0
+
+Rectangle {
+    width: 100
+    height: 100
+    color: "blue"
+
+    RotationAnimation on rotation {
+        duration: 3600
+        loops: Animation.Infinite
+        from: 0
+        to: 360
+    }
+
+    Timer {
+        interval: 300
+        repeat: true
+        running: true
+        property int prevHit: -1
+        property int prevRotation: -1
+        onTriggered: {
+            var date = new Date;
+            var millis = date.getMilliseconds()
+
+            if (prevHit < 0) {
+                prevHit = millis;
+                prevRotation = parent.rotation
+                return;
+            }
+
+            var milliDelta = millis - prevHit;
+            if (milliDelta <= 0)
+                milliDelta += 1000;
+            prevHit = millis;
+
+            var delta = parent.rotation - prevRotation;
+            if (delta < 0)
+                delta += 360
+            prevRotation = parent.rotation
+            console.log(milliDelta, delta, "ms/degrees ");
+        }
+    }
+}
diff --git a/tests/auto/qml/debugger/qqmlpreview/data/window.qml b/tests/auto/qml/debugger/qqmlpreview/data/window.qml
new file mode 100644
index 0000000000..f9f8d5aeb1
--- /dev/null
+++ b/tests/auto/qml/debugger/qqmlpreview/data/window.qml
@@ -0,0 +1,44 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.0
+import QtQuick.Window 2.0
+
+Window {
+    visible: true
+
+    height: 100
+    width: 100
+
+    Timer {
+        repeat: false
+        interval: 1000
+        running: true
+        onTriggered: console.log("window.qml");
+    }
+}
diff --git a/tests/auto/qml/debugger/qqmlpreview/data/window1.qml b/tests/auto/qml/debugger/qqmlpreview/data/window1.qml
new file mode 100644
index 0000000000..e8e9ad706d
--- /dev/null
+++ b/tests/auto/qml/debugger/qqmlpreview/data/window1.qml
@@ -0,0 +1,43 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.0
+import QtQuick.Window 2.3
+
+Window {
+    visible: true
+
+    height: 200
+    width: 100
+
+    Timer {
+        interval: 1000
+        running: true
+        onTriggered: console.log("window1.qml");
+    }
+}
diff --git a/tests/auto/qml/debugger/qqmlpreview/data/window2.qml b/tests/auto/qml/debugger/qqmlpreview/data/window2.qml
new file mode 100644
index 0000000000..9ad42d2ee2
--- /dev/null
+++ b/tests/auto/qml/debugger/qqmlpreview/data/window2.qml
@@ -0,0 +1,43 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.0
+import QtQuick.Window 2.3
+
+Window {
+    visible: true
+
+    height: 100
+    width: 200
+
+    Timer {
+        interval: 1000
+        running: true
+        onTriggered: console.log("window2.qml");
+    }
+}
diff --git a/tests/auto/qml/debugger/qqmlpreview/data/zoom.qml b/tests/auto/qml/debugger/qqmlpreview/data/zoom.qml
new file mode 100644
index 0000000000..0aca235de1
--- /dev/null
+++ b/tests/auto/qml/debugger/qqmlpreview/data/zoom.qml
@@ -0,0 +1,51 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.0
+import QtQuick.Window 2.2
+
+Window {
+    id: w
+    height: 100
+    width: 100
+    visible: true
+
+    Rectangle {
+        width: 50
+        height: 50
+        color: "blue"
+        anchors.centerIn: parent
+    }
+
+    Timer {
+        interval: 100
+        running: true
+        repeat: true
+        onTriggered: console.log("zoom", w.screen.devicePixelRatio)
+    }
+}
diff --git a/tests/auto/qml/debugger/qqmlpreview/qqmlpreview.pro b/tests/auto/qml/debugger/qqmlpreview/qqmlpreview.pro
new file mode 100644
index 0000000000..4a0d385e1a
--- /dev/null
+++ b/tests/auto/qml/debugger/qqmlpreview/qqmlpreview.pro
@@ -0,0 +1,24 @@
+CONFIG += testcase
+TARGET = tst_qqmlpreview
+
+QT += qml testlib core qmldebug-private
+macos:CONFIG -= app_bundle
+
+INCLUDEPATH += ../../../../../src/plugins/qmltooling/qmldbg_preview/
+
+SOURCES += \
+    tst_qqmlpreview.cpp \
+    ../../../../../src/plugins/qmltooling/qmldbg_preview/qqmlpreviewblacklist.cpp
+
+HEADERS += \
+    ../../../../../src/plugins/qmltooling/qmldbg_preview/qqmlpreviewblacklist.h
+
+include(../shared/debugutil.pri)
+
+TESTDATA = \
+    data/window.qml \
+    data/qtquick2.qml \
+    data/window2.qml \
+    data/window1.qml \
+    data/broken.qml \
+    data/zoom.qml
diff --git a/tests/auto/qml/debugger/qqmlpreview/tst_qqmlpreview.cpp b/tests/auto/qml/debugger/qqmlpreview/tst_qqmlpreview.cpp
new file mode 100644
index 0000000000..ebe09fbd69
--- /dev/null
+++ b/tests/auto/qml/debugger/qqmlpreview/tst_qqmlpreview.cpp
@@ -0,0 +1,307 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qqmldebugprocess_p.h"
+#include "debugutil_p.h"
+#include "qqmlpreviewblacklist.h"
+
+#include <QtTest/qtest.h>
+#include <QtTest/qsignalspy.h>
+#include <QtCore/qtimer.h>
+#include <QtCore/qdebug.h>
+#include <QtCore/qthread.h>
+#include <QtCore/qlibraryinfo.h>
+#include <QtNetwork/qhostaddress.h>
+
+#include <private/qqmldebugconnection_p.h>
+#include <private/qqmlpreviewclient_p.h>
+
+class tst_QQmlPreview : public QQmlDebugTest
+{
+    Q_OBJECT
+
+private:
+    ConnectResult startQmlProcess(const QString &qmlFile);
+    void serveRequest(const QString &path);
+    QList<QQmlDebugClient *> createClients() override;
+
+    QPointer<QQmlPreviewClient> m_client;
+
+    QStringList m_files;
+    QStringList m_filesNotFound;
+    QStringList m_directories;
+    QStringList m_serviceErrors;
+
+private slots:
+    void cleanup() final;
+
+    void connect();
+    void load();
+    void rerun();
+    void blacklist();
+    void error();
+    void zoom();
+};
+
+QQmlDebugTest::ConnectResult tst_QQmlPreview::startQmlProcess(const QString &qmlFile)
+{
+    return QQmlDebugTest::connect(QLibraryInfo::location(QLibraryInfo::BinariesPath) + "/qml",
+                                  QStringLiteral("QmlPreview"), testFile(qmlFile), true);
+}
+
+void tst_QQmlPreview::serveRequest(const QString &path)
+{
+    QFileInfo info(path);
+
+    if (info.isDir()) {
+        m_directories.append(path);
+        m_client->sendDirectory(path, QDir(path).entryList());
+    } else {
+        QFile file(path);
+        if (file.open(QIODevice::ReadOnly)) {
+            m_files.append(path);
+            m_client->sendFile(path, file.readAll());
+        } else {
+            m_filesNotFound.append(path);
+            m_client->sendError(path);
+        }
+    }
+}
+
+QList<QQmlDebugClient *> tst_QQmlPreview::createClients()
+{
+    m_client = new QQmlPreviewClient(m_connection);
+
+    QObject::connect(m_client, &QQmlPreviewClient::request, this, &tst_QQmlPreview::serveRequest);
+    QObject::connect(m_client, &QQmlPreviewClient::error, this, [this](const QString &error) {
+        m_serviceErrors.append(error);
+    });
+
+    return QList<QQmlDebugClient *>({m_client});
+}
+
+void tst_QQmlPreview::cleanup()
+{
+    QQmlDebugTest::cleanup();
+    if (QTest::currentTestFailed()) {
+        qDebug() << "Files loaded:" << m_files;
+        qDebug() << "Files not loaded:" << m_filesNotFound;
+        qDebug() << "Directories loaded:" << m_directories;
+        qDebug() << "Errors reported:" << m_serviceErrors;
+    }
+
+    m_directories.clear();
+    m_files.clear();
+    m_filesNotFound.clear();
+    m_serviceErrors.clear();
+}
+
+void tst_QQmlPreview::connect()
+{
+    const QString file("window.qml");
+    QCOMPARE(startQmlProcess(file), ConnectSuccess);
+    QVERIFY(m_client);
+    QTRY_COMPARE(m_client->state(), QQmlDebugClient::Enabled);
+    m_client->triggerLoad(testFileUrl(file));
+    QTRY_VERIFY(m_files.contains(testFile(file)));
+    QTRY_VERIFY_WITH_TIMEOUT(m_process->output().contains("qml: window.qml"), 10000);
+    m_process->stop();
+    QTRY_COMPARE(m_client->state(), QQmlDebugClient::NotConnected);
+    QVERIFY(m_serviceErrors.isEmpty());
+}
+
+void tst_QQmlPreview::load()
+{
+    const QString file("qtquick2.qml");
+    QCOMPARE(startQmlProcess(file), ConnectSuccess);
+    QVERIFY(m_client);
+    QTRY_COMPARE(m_client->state(), QQmlDebugClient::Enabled);
+    m_client->triggerLoad(testFileUrl(file));
+    QTRY_VERIFY(m_files.contains(testFile(file)));
+    QTRY_VERIFY(m_process->output().contains("ms/degrees"));
+
+    const QStringList files({"window2.qml", "window1.qml", "window.qml"});
+    for (const QString &newFile : files) {
+        m_client->triggerLoad(testFileUrl(newFile));
+        QTRY_VERIFY(m_files.contains(testFile(newFile)));
+        QTRY_VERIFY(m_process->output().contains(QString::fromLatin1("qml: %1").arg(newFile)));
+    }
+
+    m_process->stop();
+    QTRY_COMPARE(m_client->state(), QQmlDebugClient::NotConnected);
+    QVERIFY(m_serviceErrors.isEmpty());
+}
+
+void tst_QQmlPreview::rerun()
+{
+    const QString file("window.qml");
+    QCOMPARE(startQmlProcess(file), ConnectSuccess);
+    QVERIFY(m_client);
+    m_client->triggerLoad(testFileUrl(file));
+    const QLatin1String message("qml: window.qml");
+    QTRY_VERIFY(m_process->output().contains(message));
+    const int pos = m_process->output().lastIndexOf(message) + message.size();
+    QVERIFY(pos >= 0);
+
+    m_client->triggerRerun();
+    QTRY_VERIFY(m_process->output().indexOf(message, pos) >= pos);
+
+    m_process->stop();
+    QVERIFY(m_serviceErrors.isEmpty());
+}
+
+void tst_QQmlPreview::blacklist()
+{
+    QQmlPreviewBlacklist blacklist;
+
+    QStringList strings({
+        "lalala", "lulul", "trakdkd", "suppe", "zack"
+    });
+
+    for (const QString &string : strings)
+        QVERIFY(!blacklist.isBlacklisted(string));
+
+    for (const QString &string : strings)
+        blacklist.blacklist(string);
+
+    for (const QString &string : strings) {
+        QVERIFY(blacklist.isBlacklisted(string));
+        QVERIFY(!blacklist.isBlacklisted(string.left(string.size() / 2)));
+        QVERIFY(!blacklist.isBlacklisted(string + "45"));
+        QVERIFY(!blacklist.isBlacklisted(" " + string));
+        QVERIFY(blacklist.isBlacklisted(string + "/45"));
+    }
+
+    for (auto begin = strings.begin(), it = begin, end = strings.end(); it != end; ++it) {
+        std::rotate(begin, it, end);
+        QString path = "/" + strings.join('/');
+        blacklist.blacklist(path);
+        QVERIFY(blacklist.isBlacklisted(path));
+        QVERIFY(blacklist.isBlacklisted(path + "/file"));
+        QVERIFY(!blacklist.isBlacklisted(path + "more"));
+        path.chop(1);
+        QVERIFY(!blacklist.isBlacklisted(path));
+        std::reverse(begin, end);
+    }
+
+    blacklist.clear();
+    for (const QString &string : strings)
+        QVERIFY(!blacklist.isBlacklisted(string));
+
+    blacklist.blacklist(":/qt-project.org");
+    QVERIFY(blacklist.isBlacklisted(":/qt-project.org/QmlRuntime/conf/configuration.qml"));
+    QVERIFY(!blacklist.isBlacklisted(":/qt-project.orgQmlRuntime/conf/configuration.qml"));
+
+    QQmlPreviewBlacklist blacklist2;
+
+    blacklist2.blacklist(":/qt-project.org");
+    blacklist2.blacklist(":/QtQuick/Controls/Styles");
+    blacklist2.blacklist(":/ExtrasImports/QtQuick/Controls/Styles");
+    blacklist2.blacklist(QLibraryInfo::location(QLibraryInfo::Qml2ImportsPath));
+    blacklist2.blacklist("/home/ulf/.local/share/QtProject/Qml Runtime/configuration.qml");
+    blacklist2.blacklist("/usr/share");
+    blacklist2.blacklist("/usr/share/QtProject/Qml Runtime/configuration.qml");
+    QVERIFY(blacklist2.isBlacklisted(QLibraryInfo::location(QLibraryInfo::Qml2ImportsPath)));
+    blacklist2.blacklist("/usr/local/share/QtProject/Qml Runtime/configuration.qml");
+    blacklist2.blacklist("qml");
+    blacklist2.blacklist(""); // This should not remove all other paths.
+
+    QVERIFY(blacklist2.isBlacklisted(QLibraryInfo::location(QLibraryInfo::Qml2ImportsPath) +
+                                     "/QtQuick/Window.2.0"));
+    QVERIFY(blacklist2.isBlacklisted(QLibraryInfo::location(QLibraryInfo::Qml2ImportsPath)));
+    QVERIFY(blacklist2.isBlacklisted("/usr/share/QtProject/Qml Runtime/configuration.qml"));
+    QVERIFY(blacklist2.isBlacklisted("/usr/share/stuff"));
+    QVERIFY(blacklist2.isBlacklisted(""));
+
+    QQmlPreviewBlacklist blacklist3;
+    blacklist3.blacklist("/usr/share");
+    blacklist3.blacklist("/usr");
+    blacklist3.blacklist("/usrdings");
+    QVERIFY(blacklist3.isBlacklisted("/usrdings"));
+    QVERIFY(blacklist3.isBlacklisted("/usr/src"));
+    QVERIFY(!blacklist3.isBlacklisted("/opt/share"));
+    QVERIFY(!blacklist3.isBlacklisted("/opt"));
+
+    blacklist3.whitelist("/usr/share");
+    QVERIFY(blacklist3.isBlacklisted("/usrdings"));
+    QVERIFY(!blacklist3.isBlacklisted("/usr"));
+    QVERIFY(!blacklist3.isBlacklisted("/usr/share"));
+    QVERIFY(!blacklist3.isBlacklisted("/usr/src"));
+    QVERIFY(!blacklist3.isBlacklisted("/opt/share"));
+    QVERIFY(!blacklist3.isBlacklisted("/opt"));
+}
+
+void tst_QQmlPreview::error()
+{
+    QCOMPARE(startQmlProcess("window.qml"), ConnectSuccess);
+    QVERIFY(m_client);
+    m_client->triggerLoad(testFileUrl("broken.qml"));
+    QTRY_COMPARE_WITH_TIMEOUT(m_serviceErrors.count(), 1, 10000);
+    QVERIFY(m_serviceErrors.first().contains("broken.qml:32 Expected token `}'"));
+}
+
+static float parseZoomFactor(const QString &output)
+{
+    const QString prefix("zoom ");
+    const int start = output.lastIndexOf(prefix) + prefix.length();
+    if (start < 0)
+        return -1;
+    const int end = output.indexOf('\n', start);
+    if (end < 0)
+        return -1;
+    bool ok = false;
+    const float zoomFactor = output.mid(start, end - start).toFloat(&ok);
+    if (!ok)
+        return -1;
+    return zoomFactor;
+}
+
+void tst_QQmlPreview::zoom()
+{
+    const QString file("zoom.qml");
+    QCOMPARE(startQmlProcess(file), ConnectSuccess);
+    QVERIFY(m_client);
+    m_client->triggerLoad(testFileUrl(file));
+    QTRY_VERIFY(m_files.contains(testFile(file)));
+    float baseZoomFactor = -1;
+    QTRY_VERIFY((baseZoomFactor = parseZoomFactor(m_process->output())) > 0);
+    m_client->triggerZoom(2.0f);
+    QTRY_VERIFY(qFuzzyCompare(parseZoomFactor(m_process->output()), baseZoomFactor * 2.0f));
+    m_client->triggerZoom(1.5f);
+    QTRY_VERIFY(qFuzzyCompare(parseZoomFactor(m_process->output()), baseZoomFactor * 1.5f));
+    m_client->triggerZoom(0.5f);
+    QTRY_VERIFY(qFuzzyCompare(parseZoomFactor(m_process->output()), baseZoomFactor * 0.5f));
+    m_client->triggerZoom(-1.0f);
+    QTRY_VERIFY(qFuzzyCompare(parseZoomFactor(m_process->output()), baseZoomFactor));
+    m_process->stop();
+    QVERIFY(m_serviceErrors.isEmpty());
+}
+
+QTEST_MAIN(tst_QQmlPreview)
+
+#include "tst_qqmlpreview.moc"