Use the local file APIs to save/load files on WASM

QFileDialog::saveFileContent, QFileDialog::getOpenFileContent are now
using local file APIs to access files on any browser that passes a
feature check.
The feature is thoroughly tested using sinon and a new mock library.

Task-number: QTBUG-99611
Change-Id: I3dd27a9d21eb143c71ea7db0563f70ac7db3a3ac
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>

5 files changed, 650 insertions, 46 deletions

diff --git a/tests/manual/wasm/localfiles/main.cpp b/tests/manual/wasm/localfiles/main.cpp
index 46e2b058c6..39d9f21901 100644
--- a/tests/manual/wasm/localfiles/main.cpp
+++ b/tests/manual/wasm/localfiles/main.cpp
@@ -2,52 +2,136 @@
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
 #include <QtWidgets/QtWidgets>
 
+#include <emscripten/val.h>
+#include <emscripten.h>
+
+class AppWindow : public QObject
+{
+Q_OBJECT
+public:
+    AppWindow() : m_layout(new QVBoxLayout(&m_loadFileUi)),
+                  m_window(emscripten::val::global("window")),
+                  m_showOpenFilePickerFunction(m_window["showOpenFilePicker"]),
+                  m_showSaveFilePickerFunction(m_window["showSaveFilePicker"])
+    {
+        addWidget<QLabel>("Filename filter");
+
+        const bool localFileApiAvailable =
+            !m_showOpenFilePickerFunction.isUndefined() && !m_showSaveFilePickerFunction.isUndefined();
+
+        m_useLocalFileApisCheckbox = addWidget<QCheckBox>("Use the window.showXFilePicker APIs");
+        m_useLocalFileApisCheckbox->setEnabled(localFileApiAvailable);
+        m_useLocalFileApisCheckbox->setChecked(localFileApiAvailable);
+
+        m_filterEdit = addWidget<QLineEdit>("Images (*.png *.jpg);;PDF (*.pdf);;*.txt");
+
+        auto* loadFile = addWidget<QPushButton>("Load File");
+
+        m_fileInfo = addWidget<QLabel>("Opened file:");
+        m_fileInfo->setTextInteractionFlags(Qt::TextSelectableByMouse);
+
+        m_fileHash = addWidget<QLabel>("Sha256:");
+        m_fileHash->setTextInteractionFlags(Qt::TextSelectableByMouse);
+
+        addWidget<QLabel>("Saved file name");
+        m_savedFileNameEdit = addWidget<QLineEdit>("qttestresult");
+
+        m_saveFile = addWidget<QPushButton>("Save File");
+        m_saveFile->setEnabled(false);
+
+        m_layout->addStretch();
+
+        m_loadFileUi.setLayout(m_layout);
+
+        QObject::connect(m_useLocalFileApisCheckbox, &QCheckBox::toggled, std::bind(&AppWindow::onUseLocalFileApisCheckboxToggled, this));
+
+        QObject::connect(loadFile, &QPushButton::clicked, this, &AppWindow::onLoadClicked);
+
+        QObject::connect(m_saveFile, &QPushButton::clicked, std::bind(&AppWindow::onSaveClicked, this));
+    }
+
+    void show() {
+        m_loadFileUi.show();
+    }
+
+    ~AppWindow() = default;
+
+private Q_SLOTS:
+    void onUseLocalFileApisCheckboxToggled()
+    {
+        m_window.set("showOpenFilePicker",
+            m_useLocalFileApisCheckbox->isChecked() ?
+                m_showOpenFilePickerFunction : emscripten::val::undefined());
+        m_window.set("showSaveFilePicker",
+            m_useLocalFileApisCheckbox->isChecked() ?
+                m_showSaveFilePickerFunction : emscripten::val::undefined());
+    }
+
+    void onFileContentReady(const QString &fileName, const QByteArray &fileContents)
+    {
+        m_fileContent = fileContents;
+        m_fileInfo->setText(QString("Opened file: %1 size: %2").arg(fileName).arg(fileContents.size()));
+        m_saveFile->setEnabled(true);
+
+        QTimer::singleShot(100, this, &AppWindow::computeAndDisplayFileHash); // update UI before computing hash
+    }
+
+    void computeAndDisplayFileHash()
+    {
+        QByteArray hash = QCryptographicHash::hash(m_fileContent, QCryptographicHash::Sha256);
+        m_fileHash->setText(QString("Sha256: %1").arg(QString(hash.toHex())));
+    }
+
+    void onFileSaved(bool success)
+    {
+        m_fileInfo->setText(QString("File save result: %1").arg(success ? "success" : "failed"));
+    }
+
+    void onLoadClicked()
+    {
+        QFileDialog::getOpenFileContent(
+            m_filterEdit->text(),
+            std::bind(&AppWindow::onFileContentReady, this, std::placeholders::_1, std::placeholders::_2));
+    }
+
+    void onSaveClicked()
+    {
+        m_fileInfo->setText("Saving file... (no result information with current API)");
+        QFileDialog::saveFileContent(m_fileContent, m_savedFileNameEdit->text());
+    }
+
+private:
+    template <class T, class... Args>
+    T* addWidget(Args... args)
+    {
+        T* widget = new T(std::forward<Args>(args)..., &m_loadFileUi);
+        m_layout->addWidget(widget);
+        return widget;
+    }
+
+    QWidget m_loadFileUi;
+
+    QCheckBox* m_useLocalFileApisCheckbox;
+    QLineEdit* m_filterEdit;
+    QVBoxLayout *m_layout;
+    QLabel* m_fileInfo;
+    QLabel* m_fileHash;
+    QLineEdit* m_savedFileNameEdit;
+    QPushButton* m_saveFile;
+
+    emscripten::val m_window;
+    emscripten::val m_showOpenFilePickerFunction;
+    emscripten::val m_showSaveFilePickerFunction;
+
+    QByteArray m_fileContent;
+};
+
 int main(int argc, char **argv)
 {
-    QApplication app(argc, argv);
-
-    QByteArray content;
-
-    QWidget loadFileUi;
-    QVBoxLayout *layout = new QVBoxLayout();
-    QPushButton *loadFile = new QPushButton("Load File");
-    QLabel *fileInfo = new QLabel("Opened file:");
-    fileInfo->setTextInteractionFlags(Qt::TextSelectableByMouse);
-    QLabel *fileHash = new QLabel("Sha256:");
-    fileHash->setTextInteractionFlags(Qt::TextSelectableByMouse);
-    QPushButton *saveFile = new QPushButton("Save File");
-    saveFile->setEnabled(false);
-
-    auto onFileReady = [=, &content](const QString &fileName, const QByteArray &fileContents) {
-        content = fileContents;
-        fileInfo->setText(QString("Opened file: %1 size: %2").arg(fileName).arg(fileContents.size()));
-        saveFile->setEnabled(true);
-
-        auto computeDisplayFileHash = [=](){
-          QByteArray hash = QCryptographicHash::hash(fileContents, QCryptographicHash::Sha256);
-          fileHash->setText(QString("Sha256: %1").arg(QString(hash.toHex())));
-        };
-
-        QTimer::singleShot(100, computeDisplayFileHash); // update UI before computing hash
-    };
-    auto onLoadClicked = [=](){
-        QFileDialog::getOpenFileContent("*.*", onFileReady);
-    };
-    QObject::connect(loadFile, &QPushButton::clicked, onLoadClicked);
-
-    auto onSaveClicked = [=, &content]() {
-        QFileDialog::saveFileContent(content, "qtsavefiletest.dat");
-    };
-    QObject::connect(saveFile, &QPushButton::clicked, onSaveClicked);
-
-    layout->addWidget(loadFile);
-    layout->addWidget(fileInfo);
-    layout->addWidget(fileHash);
-    layout->addWidget(saveFile);
-    layout->addStretch();
-
-    loadFileUi.setLayout(layout);
-    loadFileUi.show();
-
-    return app.exec();
+    QApplication application(argc, argv);
+    AppWindow window;
+    window.show();
+    return application.exec();
 }
+
+#include "main.moc"
diff --git a/tests/manual/wasm/qstdweb/CMakeLists.txt b/tests/manual/wasm/qstdweb/CMakeLists.txt
index ea034fad67..093fe54663 100644
--- a/tests/manual/wasm/qstdweb/CMakeLists.txt
+++ b/tests/manual/wasm/qstdweb/CMakeLists.txt
@@ -20,3 +20,27 @@ add_custom_command(
     COMMAND ${CMAKE_COMMAND} -E copy
             ${CMAKE_CURRENT_SOURCE_DIR}/../qtwasmtestlib/qtwasmtestlib.js
             ${CMAKE_CURRENT_BINARY_DIR}/qtwasmtestlib.js)
+
+qt_internal_add_manual_test(files_auto
+    SOURCES
+        files_main.cpp
+        ../qtwasmtestlib/qtwasmtestlib.cpp
+    PUBLIC_LIBRARIES
+        Qt::Core
+        Qt::CorePrivate
+        Qt::GuiPrivate
+)
+
+include_directories(../qtwasmtestlib/)
+
+add_custom_command(
+    TARGET files_auto POST_BUILD
+    COMMAND ${CMAKE_COMMAND} -E copy
+            ${CMAKE_CURRENT_SOURCE_DIR}/files_auto.html
+            ${CMAKE_CURRENT_BINARY_DIR}/files_auto.html)
+
+add_custom_command(
+    TARGET files_auto POST_BUILD
+    COMMAND ${CMAKE_COMMAND} -E copy
+            ${CMAKE_CURRENT_SOURCE_DIR}/../qtwasmtestlib/qtwasmtestlib.js
+            ${CMAKE_CURRENT_BINARY_DIR}/qtwasmtestlib.js)
diff --git a/tests/manual/wasm/qstdweb/files_auto.html b/tests/manual/wasm/qstdweb/files_auto.html
new file mode 100644
index 0000000000..71e8088dfb
--- /dev/null
+++ b/tests/manual/wasm/qstdweb/files_auto.html
@@ -0,0 +1,13 @@
+<!doctype html>
+<script type="text/javascript" src="https://sinonjs.org/releases/sinon-14.0.0.js"
+    integrity="sha384-z8J4N1s2hPDn6ClmFXDQkKD/e738VOWcR8JmhztPRa+PgezxQupgZu3LzoBO4Jw8"
+    crossorigin="anonymous"></script>
+<script type="text/javascript" src="qtwasmtestlib.js"></script>
+<script type="text/javascript" src="files_auto.js"></script>
+<script>
+    window.onload = () => {
+        runTestCase(document.getElementById("log"));
+    };
+</script>
+<p>Running files auto test.</p>
+<div id="log"></div>
diff --git a/tests/manual/wasm/qstdweb/files_main.cpp b/tests/manual/wasm/qstdweb/files_main.cpp
new file mode 100644
index 0000000000..4dfae7e13b
--- /dev/null
+++ b/tests/manual/wasm/qstdweb/files_main.cpp
@@ -0,0 +1,471 @@
+// Copyright (C) 2022 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
+
+#include <QtCore/QCoreApplication>
+#include <QtCore/QEvent>
+#include <QtCore/QMutex>
+#include <QtCore/QObject>
+#include <QtCore/QTimer>
+#include <QtGui/private/qwasmlocalfileaccess_p.h>
+
+#include <qtwasmtestlib.h>
+#include <emscripten.h>
+#include <emscripten/bind.h>
+#include <emscripten/val.h>
+
+#include <string_view>
+
+using namespace emscripten;
+
+class FilesTest : public QObject
+{
+    Q_OBJECT
+
+public:
+    FilesTest() : m_window(val::global("window")), m_testSupport(val::object()) {}
+
+    ~FilesTest() noexcept {
+        for (auto& cleanup: m_cleanup) {
+            cleanup();
+        }
+    }
+
+private:
+    void init() {
+        EM_ASM({
+            window.testSupport = {};
+
+            window.showOpenFilePicker = sinon.stub();
+
+            window.mockOpenFileDialog = (files) => {
+                window.showOpenFilePicker.withArgs(sinon.match.any).callsFake(
+                    (options) => Promise.resolve(files.map(file => {
+                        const getFile = sinon.stub();
+                        getFile.callsFake(() => Promise.resolve({
+                            name: file.name,
+                            size: file.content.length,
+                            slice: () => new Blob([new TextEncoder().encode(file.content)]),
+                        }));
+                        return {
+                            kind: 'file',
+                            name: file.name,
+                            getFile
+                        };
+                    }))
+                );
+            };
+
+            window.showSaveFilePicker = sinon.stub();
+
+            window.mockSaveFilePicker = (file) => {
+                window.showSaveFilePicker.withArgs(sinon.match.any).callsFake(
+                    (options) => {
+                        const createWritable = sinon.stub();
+                        createWritable.callsFake(() => {
+                            const write = file.writeFn ?? (() => {
+                                const write = sinon.stub();
+                                write.callsFake((stuff) => {
+                                    if (file.content !== new TextDecoder().decode(stuff)) {
+                                        const message = `Bad file content ${file.content} !== ${new TextDecoder().decode(stuff)}`;
+                                        Module.qtWasmFail(message);
+                                        return Promise.reject(message);
+                                    }
+
+                                    return Promise.resolve();
+                                });
+                                return write;
+                            })();
+
+                            window.testSupport.write = write;
+
+                            const close = file.closeFn ?? (() => {
+                                const close = sinon.stub();
+                                close.callsFake(() => Promise.resolve());
+                                return close;
+                            })();
+
+                            window.testSupport.close = close;
+
+                            return Promise.resolve({
+                                write,
+                                close
+                            });
+                        });
+                        return Promise.resolve({
+                            kind: 'file',
+                            name: file.name,
+                            createWritable
+                        });
+                    }
+                );
+            };
+        });
+    }
+
+    template <class T>
+    T* Own(T* plainPtr) {
+        m_cleanup.emplace_back([plainPtr]() mutable {
+            delete plainPtr;
+        });
+        return plainPtr;
+    }
+
+    val m_window;
+    val m_testSupport;
+
+    std::vector<std::function<void()>> m_cleanup;
+
+private slots:
+    void selectOneFileWithFileDialog();
+    void selectMultipleFilesWithFileDialog();
+    void cancelFileDialog();
+    void rejectFile();
+    void saveFileWithFileDialog();
+};
+
+class BarrierCallback {
+public:
+    BarrierCallback(int number, std::function<void()> onDone)
+        : m_remaining(number), m_onDone(std::move(onDone)) {}
+
+    void operator()() {
+        if (!--m_remaining) {
+            m_onDone();
+        }
+    }
+
+private:
+    int m_remaining;
+    std::function<void()> m_onDone;
+};
+
+
+template <class Arg>
+std::string argToString(std::add_lvalue_reference_t<std::add_const_t<Arg>> arg) {
+    return std::to_string(arg);
+}
+
+template <>
+std::string argToString<bool>(const bool& value) {
+    return value ? "true" : "false";
+}
+
+template <>
+std::string argToString<std::string>(const std::string& arg) {
+    return arg;
+}
+
+template <>
+std::string argToString<const std::string&>(const std::string& arg) {
+    return arg;
+}
+
+template<class Type>
+struct Matcher {
+    virtual ~Matcher() = default;
+
+    virtual bool matches(std::string* explanation, const Type& actual) const = 0;
+};
+
+template<class Type>
+struct AnyMatcher : public Matcher<Type> {
+    bool matches(std::string* explanation, const Type& actual) const final {
+        Q_UNUSED(explanation);
+        Q_UNUSED(actual);
+        return true;
+    }
+
+    Type m_value;
+};
+
+template<class Type>
+struct EqualsMatcher : public Matcher<Type> {
+    EqualsMatcher(Type value) : m_value(std::forward<Type>(value)) {}
+
+    bool matches(std::string* explanation, const Type& actual) const final {
+        const bool ret = actual == m_value;
+        if (!ret)
+            *explanation += argToString<Type>(actual) + " != " + argToString<Type>(m_value);
+        return actual == m_value;
+    }
+
+    // It is crucial to hold a copy, otherwise we lose const refs.
+    std::remove_reference_t<Type> m_value;
+};
+
+template<class Type>
+std::unique_ptr<EqualsMatcher<Type>> equals(Type value) {
+    return std::make_unique<EqualsMatcher<Type>>(value);
+}
+
+template<class Type>
+std::unique_ptr<AnyMatcher<Type>> any(Type value) {
+    return std::make_unique<AnyMatcher<Type>>(value);
+}
+
+template <class ...Types>
+struct Expectation {
+    std::tuple<std::unique_ptr<Matcher<Types>>...> m_argMatchers;
+    int m_callCount = 0;
+    int m_expectedCalls = 1;
+
+    template<std::size_t... Indices>
+    bool match(std::string* explanation, const std::tuple<Types...>& tuple, std::index_sequence<Indices...>) const {
+        return ( ... && (std::get<Indices>(m_argMatchers)->matches(explanation, std::get<Indices>(tuple))));
+    }
+
+    bool matches(std::string* explanation, Types... args) const {
+        if (m_callCount >= m_expectedCalls) {
+            *explanation += "Too many calls\n";
+            return false;
+        }
+        return match(explanation, std::make_tuple(args...), std::make_index_sequence<std::tuple_size_v<std::tuple<Types...>>>());
+    }
+};
+
+template <class R, class ...Types>
+struct Behavior {
+    std::function<R(Types...)> m_callback;
+
+    void call(std::function<R(Types...)> callback) {
+        m_callback = std::move(callback);
+    }
+};
+
+template<class... Args>
+std::string argsToString(Args... args) {
+    return (... + (", " + argToString<Args>(args)));
+}
+
+template<>
+std::string argsToString<>() {
+    return "";
+}
+
+template<class R, class ...Types>
+struct ExpectationToBehaviorMapping {
+    Expectation<Types...> expectation;
+    Behavior<R, Types...> behavior;
+};
+
+template<class R, class... Args>
+class MockCallback {
+public:
+    std::function<R(Args...)> get() {
+        return [this](Args... result) -> R {
+            return processCall(std::forward<Args>(result)...);
+        };
+    }
+
+    Behavior<R, Args...>& expectCallWith(std::unique_ptr<Matcher<Args>>... matcherArgs) {
+        auto matchers = std::make_tuple(std::move(matcherArgs)...);
+        m_behaviorByExpectation.push_back({Expectation<Args...> {std::move(matchers)}, Behavior<R, Args...> {}});
+        return m_behaviorByExpectation.back().behavior;
+    }
+
+    Behavior<R, Args...>& expectRepeatedCallWith(int times, std::unique_ptr<Matcher<Args>>... matcherArgs) {
+        auto matchers = std::make_tuple(std::move(matcherArgs)...);
+        m_behaviorByExpectation.push_back({Expectation<Args...> {std::move(matchers), 0, times}, Behavior<R, Args...> {}});
+        return m_behaviorByExpectation.back().behavior;
+    }
+
+private:
+    R processCall(Args... args) {
+        std::string argsAsString = argsToString(args...);
+        std::string triedExpectations;
+        auto it = std::find_if(m_behaviorByExpectation.begin(), m_behaviorByExpectation.end(),
+            [&](const ExpectationToBehaviorMapping<R, Args...>& behavior) {
+                return behavior.expectation.matches(&triedExpectations, std::forward<Args>(args)...);
+            });
+        if (it != m_behaviorByExpectation.end()) {
+            ++it->expectation.m_callCount;
+            return it->behavior.m_callback(args...);
+        } else {
+            QWASMFAIL("Unexpected call with " + argsAsString + ". Tried: " + triedExpectations);
+        }
+        return R();
+    }
+
+    std::vector<ExpectationToBehaviorMapping<R, Args...>> m_behaviorByExpectation;
+};
+
+void FilesTest::selectOneFileWithFileDialog()
+{
+    init();
+
+    static constexpr std::string_view testFileContent = "This is a happy case.";
+
+    EM_ASM({
+        mockOpenFileDialog([{
+            name: 'file1.jpg',
+            content: UTF8ToString($0)
+        }]);
+    }, testFileContent.data());
+
+    auto* fileSelectedCallback = Own(new MockCallback<void, bool>());
+    fileSelectedCallback->expectCallWith(equals(true)).call([](bool) mutable {});
+
+    auto* fileBuffer = Own(new QByteArray());
+
+    auto* acceptFileCallback = Own(new MockCallback<char*, uint64_t, const std::string&>());
+    acceptFileCallback->expectCallWith(equals<uint64_t>(testFileContent.size()), equals<const std::string&>("file1.jpg"))
+        .call([fileBuffer](uint64_t, std::string) mutable -> char* {
+            fileBuffer->resize(testFileContent.size());
+            return fileBuffer->data();
+        });
+
+    auto* fileDataReadyCallback = Own(new MockCallback<void>());
+    fileDataReadyCallback->expectCallWith().call([fileBuffer]() mutable {
+        QWASMCOMPARE(fileBuffer->data(), std::string(testFileContent));
+        QWASMSUCCESS();
+    });
+
+    QWasmLocalFileAccess::openFile(
+        {QStringLiteral("*")}, fileSelectedCallback->get(), acceptFileCallback->get(), fileDataReadyCallback->get());
+}
+
+void FilesTest::selectMultipleFilesWithFileDialog()
+{
+    static constexpr std::array<std::string_view, 3> testFileContent =
+        { "Cont 1", "2s content", "What is hiding in 3?"};
+
+    init();
+
+    EM_ASM({
+        mockOpenFileDialog([{
+            name: 'file1.jpg',
+            content: UTF8ToString($0)
+        }, {
+            name: 'file2.jpg',
+            content: UTF8ToString($1)
+        }, {
+            name: 'file3.jpg',
+            content: UTF8ToString($2)
+        }]);
+    }, testFileContent[0].data(), testFileContent[1].data(), testFileContent[2].data());
+
+    auto* fileSelectedCallback = Own(new MockCallback<void, int>());
+    fileSelectedCallback->expectCallWith(equals(3)).call([](int) mutable {});
+
+    auto fileBuffer = std::make_shared<QByteArray>();
+
+    auto* acceptFileCallback = Own(new MockCallback<char*, uint64_t, const std::string&>());
+    acceptFileCallback->expectCallWith(equals<uint64_t>(testFileContent[0].size()), equals<const std::string&>("file1.jpg"))
+        .call([fileBuffer](uint64_t, std::string) mutable -> char* {
+            fileBuffer->resize(testFileContent[0].size());
+            return fileBuffer->data();
+        });
+    acceptFileCallback->expectCallWith(equals<uint64_t>(testFileContent[1].size()), equals<const std::string&>("file2.jpg"))
+        .call([fileBuffer](uint64_t, std::string) mutable -> char* {
+            fileBuffer->resize(testFileContent[1].size());
+            return fileBuffer->data();
+        });
+    acceptFileCallback->expectCallWith(equals<uint64_t>(testFileContent[2].size()), equals<const std::string&>("file3.jpg"))
+        .call([fileBuffer](uint64_t, std::string) mutable -> char* {
+            fileBuffer->resize(testFileContent[2].size());
+            return fileBuffer->data();
+        });
+
+    auto* fileDataReadyCallback = Own(new MockCallback<void>());
+    fileDataReadyCallback->expectRepeatedCallWith(3).call([fileBuffer]() mutable {
+        static int callCount = 0;
+        QWASMCOMPARE(fileBuffer->data(), std::string(testFileContent[callCount]));
+
+        callCount++;
+        if (callCount == 3) {
+            QWASMSUCCESS();
+        }
+    });
+
+    QWasmLocalFileAccess::openFiles(
+        {QStringLiteral("*")}, QWasmLocalFileAccess::FileSelectMode::MultipleFiles,
+        fileSelectedCallback->get(), acceptFileCallback->get(), fileDataReadyCallback->get());
+}
+
+void FilesTest::cancelFileDialog()
+{
+    init();
+
+    EM_ASM({
+        window.showOpenFilePicker.withArgs(sinon.match.any).returns(Promise.reject("The user cancelled the dialog"));
+    });
+
+    auto* fileSelectedCallback = Own(new MockCallback<void, bool>());
+    fileSelectedCallback->expectCallWith(equals(false)).call([](bool) mutable {
+        QWASMSUCCESS();
+    });
+
+    auto* acceptFileCallback = Own(new MockCallback<char*, uint64_t, const std::string&>());
+    auto* fileDataReadyCallback = Own(new MockCallback<void>());
+
+    QWasmLocalFileAccess::openFile(
+        {QStringLiteral("*")}, fileSelectedCallback->get(), acceptFileCallback->get(), fileDataReadyCallback->get());
+}
+
+void FilesTest::rejectFile()
+{
+    init();
+
+    static constexpr std::string_view testFileContent = "We don't want this file.";
+
+    EM_ASM({
+        mockOpenFileDialog([{
+            name: 'dontwant.dat',
+            content: UTF8ToString($0)
+        }]);
+    }, testFileContent.data());
+
+    auto* fileSelectedCallback = Own(new MockCallback<void, bool>());
+    fileSelectedCallback->expectCallWith(equals(true)).call([](bool) mutable {});
+
+    auto* fileDataReadyCallback = Own(new MockCallback<void>());
+
+    auto* acceptFileCallback = Own(new MockCallback<char*, uint64_t, const std::string&>());
+    acceptFileCallback->expectCallWith(equals<uint64_t>(std::string_view(testFileContent).size()), equals<const std::string&>("dontwant.dat"))
+        .call([](uint64_t, const std::string) {
+            QTimer::singleShot(0, []() {
+                // No calls to fileDataReadyCallback
+                QWASMSUCCESS();
+            });
+            return nullptr;
+        });
+
+    QWasmLocalFileAccess::openFile(
+        {QStringLiteral("*")}, fileSelectedCallback->get(), acceptFileCallback->get(), fileDataReadyCallback->get());
+}
+
+void FilesTest::saveFileWithFileDialog()
+{
+    init();
+
+    static constexpr std::string_view testFileContent = "Save this important content";
+
+    EM_ASM({
+        mockSaveFilePicker({
+            name: 'somename',
+            content: UTF8ToString($0),
+            closeFn: (() => {
+                const close = sinon.stub();
+                close.callsFake(() =>
+                    new Promise(resolve => {
+                        resolve();
+                        Module.qtWasmPass();
+                    }));
+                return close;
+            })()
+        });
+    }, testFileContent.data());
+
+    QByteArray data;
+    data.prepend(testFileContent);
+    QWasmLocalFileAccess::saveFile(data, "hintie");
+}
+
+int main(int argc, char **argv)
+{
+    auto testObject = std::make_shared<FilesTest>();
+    QtWasmTest::initTestCase<QCoreApplication>(argc, argv, testObject);
+    return 0;
+}
+
+#include "files_main.moc"
diff --git a/tests/manual/wasm/qtwasmtestlib/qtwasmtestlib.cpp b/tests/manual/wasm/qtwasmtestlib/qtwasmtestlib.cpp
index c70c390249..7d1db44cb0 100644
--- a/tests/manual/wasm/qtwasmtestlib/qtwasmtestlib.cpp
+++ b/tests/manual/wasm/qtwasmtestlib/qtwasmtestlib.cpp
@@ -101,10 +101,22 @@ void runTestFunction(std::string name)
     QMetaObject::invokeMethod(g_testObject, name.c_str());
 }
 
+void failTest(std::string message)
+{
+    completeTestFunction(QtWasmTest::Fail, std::move(message));
+}
+
+void passTest()
+{
+    completeTestFunction(QtWasmTest::Pass, "");
+}
+
 EMSCRIPTEN_BINDINGS(qtwebtestrunner) {
     emscripten::function("cleanupTestCase", &cleanupTestCase);
     emscripten::function("getTestFunctions", &getTestFunctions);
     emscripten::function("runTestFunction", &runTestFunction);
+    emscripten::function("qtWasmFail", &failTest);
+    emscripten::function("qtWasmPass", &passTest);
 }
 
 //