diff --git a/CMakeLists.txt b/CMakeLists.txt
index a5864ffdcbb..a2324cd8d7c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -624,6 +624,9 @@ ADD_DEFINITIONS(-DQT_DEPRECATED_WARNINGS)
 # Unfortunately Qwt uses deprecated QString::null in headers, preventing this being raised above 5.8
 ADD_DEFINITIONS(-DQT_DISABLE_DEPRECATED_BEFORE=0x050800)
 
+# For fast string concatenation
+ADD_DEFINITIONS(-DQT_USE_QSTRINGBUILDER)
+
 IF (WITH_GEOREFERENCER)
   FIND_PACKAGE(GSL REQUIRED)
   SET(HAVE_GEOREFERENCER TRUE)
diff --git a/src/analysis/processing/qgsalgorithmlayouttoimage.cpp b/src/analysis/processing/qgsalgorithmlayouttoimage.cpp
index 1f2dc530389..d99dd614123 100644
--- a/src/analysis/processing/qgsalgorithmlayouttoimage.cpp
+++ b/src/analysis/processing/qgsalgorithmlayouttoimage.cpp
@@ -92,7 +92,7 @@ void QgsLayoutToImageAlgorithm::initAlgorithm( const QVariantMap & )
       continue;
 
     QString longName = format.toUpper() + QObject::tr( " format" );
-    QString glob = "*." + format;
+    QString glob = QStringLiteral( "*." ) + format;
 
     if ( format == "png" && !imageFilters.empty() )
       imageFilters.insert( 0, QStringLiteral( "%1 (%2 %3)" ).arg( longName, glob.toLower(), glob.toUpper() ) );
diff --git a/src/analysis/processing/qgsalgorithmstringconcatenation.cpp b/src/analysis/processing/qgsalgorithmstringconcatenation.cpp
index 97579d7f257..8a9dda63575 100644
--- a/src/analysis/processing/qgsalgorithmstringconcatenation.cpp
+++ b/src/analysis/processing/qgsalgorithmstringconcatenation.cpp
@@ -72,7 +72,7 @@ QVariantMap QgsStringConcatenationAlgorithm::processAlgorithm( const QVariantMap
   QString input_2 = parameterAsString( parameters, QStringLiteral( "INPUT_2" ), context );
 
   QVariantMap outputs;
-  outputs.insert( QStringLiteral( "CONCATENATION" ), input_1 + input_2 );
+  outputs.insert( QStringLiteral( "CONCATENATION" ), QString( input_1 + input_2 ) );
   return outputs;
 }
 
diff --git a/src/analysis/processing/qgsprojectstylealgorithms.cpp b/src/analysis/processing/qgsprojectstylealgorithms.cpp
index dd79d0c7982..730c7b0f09b 100644
--- a/src/analysis/processing/qgsprojectstylealgorithms.cpp
+++ b/src/analysis/processing/qgsprojectstylealgorithms.cpp
@@ -34,7 +34,7 @@ bool QgsSaveToStyleVisitor::visit( const QgsStyleEntityVisitorInterface::StyleLe
 {
   if ( mObjects.empty() || mObjects.contains( entity.entity->type() ) )
   {
-    const QString name = ( mParentNames.join( ' ' ) + ' ' + entity.description ).trimmed();
+    const QString name = QString( mParentNames.join( ' ' ) + ' ' + entity.description ).trimmed();
     QString candidate = name;
     int i = 1;
     bool exists = true;
diff --git a/src/app/options/qgsoptions.cpp b/src/app/options/qgsoptions.cpp
index 4fd17b8df3e..cb3e1289c42 100644
--- a/src/app/options/qgsoptions.cpp
+++ b/src/app/options/qgsoptions.cpp
@@ -793,7 +793,7 @@ QgsOptions::QgsOptions( QWidget *parent, Qt::WindowFlags fl, const QList<QgsOpti
   // templates
   cbxProjectDefaultNew->setChecked( mSettings->value( QStringLiteral( "/qgis/newProjectDefault" ), QVariant( false ) ).toBool() );
   QString templateDirName = mSettings->value( QStringLiteral( "/qgis/projectTemplateDir" ),
-                            QgsApplication::qgisSettingsDirPath() + "project_templates" ).toString();
+                            QString( QgsApplication::qgisSettingsDirPath() + "project_templates" ) ).toString();
   // make dir if it doesn't exist - should just be called once
   QDir templateDir;
   if ( ! templateDir.exists( templateDirName ) )
diff --git a/src/app/qgisapp.cpp b/src/app/qgisapp.cpp
index 9b9f9244e79..1542183a5b3 100644
--- a/src/app/qgisapp.cpp
+++ b/src/app/qgisapp.cpp
@@ -1117,7 +1117,7 @@ QgisApp::QgisApp( QSplashScreen *splash, bool restorePlugins, bool skipVersionCh
   mSaveRollbackInProgress = false;
 
   QString templateDirName = settings.value( QStringLiteral( "qgis/projectTemplateDir" ),
-                            QgsApplication::qgisSettingsDirPath() + "project_templates" ).toString();
+                            QString( QgsApplication::qgisSettingsDirPath() + "project_templates" ) ).toString();
   if ( !QFileInfo::exists( templateDirName ) )
   {
     // create default template directory
@@ -5049,7 +5049,7 @@ void QgisApp::saveRecentProjectPath( bool savePreviewImage, const QIcon &iconOve
   QgsRecentProjectItemsModel::RecentProjectData projectData;
   projectData.path = QgsProject::instance()->absoluteFilePath();
   QString templateDirName = QgsSettings().value( QStringLiteral( "qgis/projectTemplateDir" ),
-                            QgsApplication::qgisSettingsDirPath() + "project_templates" ).toString();
+                            QString( QgsApplication::qgisSettingsDirPath() + "project_templates" ) ).toString();
 
   // We don't want the template path to appear in the recent projects list. Never.
   if ( projectData.path.startsWith( templateDirName ) )
@@ -5160,7 +5160,7 @@ void QgisApp::updateProjectFromTemplates()
   // get list of project files in template dir
   QgsSettings settings;
   QString templateDirName = settings.value( QStringLiteral( "qgis/projectTemplateDir" ),
-                            QgsApplication::qgisSettingsDirPath() + "project_templates" ).toString();
+                            QString( QgsApplication::qgisSettingsDirPath() + "project_templates" ) ).toString();
   QDir templateDir( templateDirName );
   QStringList filters( QStringLiteral( "*.qgs" ) );
   filters << QStringLiteral( "*.qgz" );
@@ -6672,7 +6672,7 @@ void QgisApp::fileNewFromTemplateAction( QAction *qAction )
   {
     QgsSettings settings;
     QString templateDirName = settings.value( QStringLiteral( "qgis/projectTemplateDir" ),
-                              QgsApplication::qgisSettingsDirPath() + "project_templates" ).toString();
+                              QString( QgsApplication::qgisSettingsDirPath() + "project_templates" ) ).toString();
     fileNewFromTemplate( templateDirName + QDir::separator() + qAction->text() );
   }
 }
@@ -7243,7 +7243,7 @@ void QgisApp::fileSaveAs()
     // Retrieve last used project dir from persistent settings
     QgsSettings settings;
     defaultPath = settings.value( QStringLiteral( "UI/lastProjectDir" ), QDir::homePath() ).toString();
-    defaultPath += + '/' + QgsProject::instance()->title();
+    defaultPath += QString( '/' + QgsProject::instance()->title() );
   }
 
   const QString qgsExt = tr( "QGIS files" ) + " (*.qgs *.QGS)";
@@ -16484,7 +16484,7 @@ void QgisApp::populateProjectStorageMenu( QMenu *menu, const bool saving )
     {
       QgsSettings settings;
       QString templateDirName = settings.value( QStringLiteral( "qgis/projectTemplateDir" ),
-          QgsApplication::qgisSettingsDirPath() + "project_templates" ).toString();
+          QString( QgsApplication::qgisSettingsDirPath() + "project_templates" ) ).toString();
 
       const QString originalFilename = QgsProject::instance()->fileName();
       QString templateName = QFileInfo( originalFilename ).baseName();
diff --git a/src/app/qgsabout.cpp b/src/app/qgsabout.cpp
index 94c4693f236..932faa53af0 100644
--- a/src/app/qgsabout.cpp
+++ b/src/app/qgsabout.cpp
@@ -233,7 +233,7 @@ void QgsAbout::setWhatsNew()
   if ( !QFile::exists( QgsApplication::pkgDataPath() + "/doc/NEWS.html" ) )
     return;
 
-  txtWhatsNew->setSource( "file:///" + QgsApplication::pkgDataPath() + "/doc/NEWS.html" );
+  txtWhatsNew->setSource( QString( "file:///" + QgsApplication::pkgDataPath() + "/doc/NEWS.html" ) );
 }
 
 void QgsAbout::setPluginInfo()
diff --git a/src/app/qgsidentifyresultsdialog.cpp b/src/app/qgsidentifyresultsdialog.cpp
index 14c553aed94..984818d42a6 100644
--- a/src/app/qgsidentifyresultsdialog.cpp
+++ b/src/app/qgsidentifyresultsdialog.cpp
@@ -574,7 +574,7 @@ void QgsIdentifyResultsDialog::addFeature( QgsVectorLayer *vlayer, const QgsFeat
 
     item = new QTableWidgetItem( QString::number( i ) );
     if ( fields.at( i ).name() == vlayer->displayField() )
-      item->setData( Qt::DisplayRole, vlayer->attributeDisplayName( i ) + " *" );
+      item->setData( Qt::DisplayRole, QString( vlayer->attributeDisplayName( i ) + " *" ) );
     else
       item->setData( Qt::DisplayRole, vlayer->attributeDisplayName( i ) );
     item->setData( Qt::UserRole, fields.at( i ).name() );
diff --git a/src/app/qgstemplateprojectsmodel.cpp b/src/app/qgstemplateprojectsmodel.cpp
index b6a8e82b802..5b0102f8885 100644
--- a/src/app/qgstemplateprojectsmodel.cpp
+++ b/src/app/qgstemplateprojectsmodel.cpp
@@ -34,7 +34,7 @@ QgsTemplateProjectsModel::QgsTemplateProjectsModel( QObject *parent )
 {
   const QStringList paths = QStandardPaths::standardLocations( QStandardPaths::AppDataLocation );
   QString templateDirName = QgsSettings().value( QStringLiteral( "qgis/projectTemplateDir" ),
-                            QgsApplication::qgisSettingsDirPath() + QStringLiteral( "project_templates" ) ).toString();
+                            QString( QgsApplication::qgisSettingsDirPath() + QStringLiteral( "project_templates" ) ) ).toString();
 
   for ( const QString &templatePath : paths )
   {
diff --git a/src/core/layout/qgslayoutitemhtml.cpp b/src/core/layout/qgslayoutitemhtml.cpp
index 5bf72963559..1980bcc6bef 100644
--- a/src/core/layout/qgslayoutitemhtml.cpp
+++ b/src/core/layout/qgslayoutitemhtml.cpp
@@ -198,7 +198,7 @@ void QgsLayoutItemHtml::loadHtml( const bool useCache, const QgsExpressionContex
   {
     QByteArray ba;
     ba.append( mUserStylesheet.toUtf8() );
-    QUrl cssFileURL = QUrl( "data:text/css;charset=utf-8;base64," + ba.toBase64() );
+    QUrl cssFileURL = QUrl( QString( "data:text/css;charset=utf-8;base64," + ba.toBase64() ) );
     settings->setUserStyleSheetUrl( cssFileURL );
   }
   else
diff --git a/src/core/layout/qgslayoutitemlabel.cpp b/src/core/layout/qgslayoutitemlabel.cpp
index 4ee7f74d539..e43874f9329 100644
--- a/src/core/layout/qgslayoutitemlabel.cpp
+++ b/src/core/layout/qgslayoutitemlabel.cpp
@@ -611,7 +611,7 @@ QUrl QgsLayoutItemLabel::createStylesheetUrl() const
 
   QByteArray ba;
   ba.append( stylesheet.toUtf8() );
-  QUrl cssFileURL = QUrl( "data:text/css;charset=utf-8;base64," + ba.toBase64() );
+  QUrl cssFileURL = QUrl( QString( "data:text/css;charset=utf-8;base64," + ba.toBase64() ) );
 
   return cssFileURL;
 }
diff --git a/src/core/processing/qgsprocessingutils.cpp b/src/core/processing/qgsprocessingutils.cpp
index 46fbcf97e92..6198194dd69 100644
--- a/src/core/processing/qgsprocessingutils.cpp
+++ b/src/core/processing/qgsprocessingutils.cpp
@@ -908,14 +908,14 @@ QVariant QgsProcessingUtils::generateIteratingDestination( const QVariant &input
     }
     else if ( res.startsWith( QLatin1String( "memory:" ) ) )
     {
-      return res + '_' + id.toString();
+      return QString( res + '_' + id.toString() );
     }
     else
     {
       // assume a filename type output for now
       // TODO - uris?
       int lastIndex = res.lastIndexOf( '.' );
-      return res.left( lastIndex ) + '_' + id.toString() + res.mid( lastIndex );
+      return QString( res.left( lastIndex ) + '_' + id.toString() + res.mid( lastIndex ) );
     }
   }
 }
diff --git a/src/core/qgsnetworkaccessmanager.h b/src/core/qgsnetworkaccessmanager.h
index f5f22963cb8..97ca9ee06cb 100644
--- a/src/core/qgsnetworkaccessmanager.h
+++ b/src/core/qgsnetworkaccessmanager.h
@@ -38,8 +38,8 @@ class QgsFeedback;
 #include "qgsconfig.h"
 constexpr int sFilePrefixLength = CMAKE_SOURCE_DIR[sizeof( CMAKE_SOURCE_DIR ) - 1] == '/' ? sizeof( CMAKE_SOURCE_DIR ) + 1 : sizeof( CMAKE_SOURCE_DIR );
 
-#define QgsSetRequestInitiatorClass(request, _class) request.setAttribute( static_cast< QNetworkRequest::Attribute >( QgsNetworkRequestParameters::AttributeInitiatorClass ), _class ); request.setAttribute( static_cast< QNetworkRequest::Attribute >( QgsNetworkRequestParameters::AttributeInitiatorRequestId ), QString( __FILE__ ).mid( sFilePrefixLength ) + ':' + QString::number( __LINE__ ) + " (" + __FUNCTION__ + ")" );
-#define QgsSetRequestInitiatorId(request, str) request.setAttribute( static_cast< QNetworkRequest::Attribute >( QgsNetworkRequestParameters::AttributeInitiatorRequestId ), QString( __FILE__ ).mid( sFilePrefixLength ) + ':' + QString::number( __LINE__ ) + " (" + __FUNCTION__ + "): " + str );
+#define QgsSetRequestInitiatorClass(request, _class) request.setAttribute( static_cast< QNetworkRequest::Attribute >( QgsNetworkRequestParameters::AttributeInitiatorClass ), _class ); request.setAttribute( static_cast< QNetworkRequest::Attribute >( QgsNetworkRequestParameters::AttributeInitiatorRequestId ), QString(QString( __FILE__ ).mid( sFilePrefixLength ) + ':' + QString::number( __LINE__ ) + " (" + __FUNCTION__ + ")") );
+#define QgsSetRequestInitiatorId(request, str) request.setAttribute( static_cast< QNetworkRequest::Attribute >( QgsNetworkRequestParameters::AttributeInitiatorRequestId ), QString(QString( __FILE__ ).mid( sFilePrefixLength ) + ':' + QString::number( __LINE__ ) + " (" + __FUNCTION__ + "): " + str) );
 #endif
 
 /**
diff --git a/src/core/symbology/qgscptcityarchive.cpp b/src/core/symbology/qgscptcityarchive.cpp
index 7c0abe344a7..5b20320163d 100644
--- a/src/core/symbology/qgscptcityarchive.cpp
+++ b/src/core/symbology/qgscptcityarchive.cpp
@@ -138,7 +138,7 @@ QString QgsCptCityArchive::defaultBaseDir()
 
   // use CptCity/baseDir setting if set, default is user dir
   baseDir = settings.value( QStringLiteral( "CptCity/baseDir" ),
-                            QgsApplication::pkgDataPath() + "/resources" ).toString();
+                            QString( QgsApplication::pkgDataPath() + "/resources" ) ).toString();
   // sub-dir defaults to cpt-city
   archiveName = settings.value( QStringLiteral( "CptCity/archiveName" ), DEFAULT_CPTCITY_ARCHIVE ).toString();
 
@@ -447,7 +447,7 @@ void QgsCptCityArchive::initDefaultArchive()
   QgsSettings settings;
   // use CptCity/baseDir setting if set, default is user dir
   QString baseDir = settings.value( QStringLiteral( "CptCity/baseDir" ),
-                                    QgsApplication::pkgDataPath() + "/resources" ).toString();
+                                    QString( QgsApplication::pkgDataPath() + "/resources" ) ).toString();
   // sub-dir defaults to
   QString defArchiveName = settings.value( QStringLiteral( "CptCity/archiveName" ), DEFAULT_CPTCITY_ARCHIVE ).toString();
 
@@ -463,7 +463,7 @@ void QgsCptCityArchive::initArchives( bool loadAll )
 
   // use CptCity/baseDir setting if set, default is user dir
   baseDir = settings.value( QStringLiteral( "CptCity/baseDir" ),
-                            QgsApplication::pkgDataPath() + "/resources" ).toString();
+                            QString( QgsApplication::pkgDataPath() + "/resources" ) ).toString();
   // sub-dir defaults to
   defArchiveName = settings.value( QStringLiteral( "CptCity/archiveName" ), DEFAULT_CPTCITY_ARCHIVE ).toString();
 
@@ -1312,7 +1312,7 @@ QgsCptCityBrowserModel::QgsCptCityBrowserModel( QObject *parent,
   , mViewType( viewType )
 {
   Q_ASSERT( mArchive );
-  QgsDebugMsg( "archiveName = " + archive->archiveName() + " viewType=" + static_cast< int >( viewType ) );
+  QgsDebugMsg( QLatin1String( "archiveName = " ) + archive->archiveName() + " viewType=" + QString::number( static_cast< int >( viewType ) ) );
   // keep iconsize for now, but not effectively used
   mIconSize = QSize( 100, 15 );
   addRootItems();
@@ -1381,7 +1381,7 @@ QVariant QgsCptCityBrowserModel::data( const QModelIndex &index, int role ) cons
   {
     if ( item->type() == QgsCptCityDataItem::ColorRamp &&
          mViewType == List )
-      return item->path() + '\n' + item->info();
+      return QString( item->path() + '\n' + item->info() );
     return item->toolTip();
   }
   else if ( role == Qt::DecorationRole && index.column() == 1 &&
diff --git a/src/core/vectortile/qgsmapboxglstyleconverter.cpp b/src/core/vectortile/qgsmapboxglstyleconverter.cpp
index 782f6c3d121..2c6d75c7653 100644
--- a/src/core/vectortile/qgsmapboxglstyleconverter.cpp
+++ b/src/core/vectortile/qgsmapboxglstyleconverter.cpp
@@ -2303,7 +2303,7 @@ QString QgsMapBoxGlStyleConverter::parseExpression( const QVariantList &expressi
   {
     // ! inverts next expression's meaning
     QVariantList contraJsonExpr = expression.value( 1 ).toList();
-    contraJsonExpr[0] = op + contraJsonExpr[0].toString();
+    contraJsonExpr[0] = QString( op + contraJsonExpr[0].toString() );
     // ['!', ['has', 'level']] -> ['!has', 'level']
     return parseKey( contraJsonExpr );
   }
diff --git a/src/gui/locator/qgslocatorwidget.cpp b/src/gui/locator/qgslocatorwidget.cpp
index 7192a2d0d2e..657fe5a833b 100644
--- a/src/gui/locator/qgslocatorwidget.cpp
+++ b/src/gui/locator/qgslocatorwidget.cpp
@@ -439,7 +439,7 @@ void QgsLocatorFilterFilter::fetchResults( const QString &string, const QgsLocat
     QgsLocatorResult result;
     result.displayString = filter->activePrefix();
     result.description = filter->displayName();
-    result.userData = filter->activePrefix() + ' ';
+    result.userData = QString( filter->activePrefix() + ' ' );
     result.icon = QgsApplication::getThemeIcon( QStringLiteral( "/search.svg" ) );
     emit resultFetched( result );
   }
diff --git a/src/gui/symbology/qgsgraduatedsymbolrendererwidget.cpp b/src/gui/symbology/qgsgraduatedsymbolrendererwidget.cpp
index 717911cbcfa..338620756b9 100644
--- a/src/gui/symbology/qgsgraduatedsymbolrendererwidget.cpp
+++ b/src/gui/symbology/qgsgraduatedsymbolrendererwidget.cpp
@@ -165,7 +165,7 @@ QVariant QgsGraduatedSymbolRendererModel::data( const QModelIndex &index, int ro
       {
         int decimalPlaces = mRenderer->classificationMethod()->labelPrecision() + 2;
         if ( decimalPlaces < 0 ) decimalPlaces = 0;
-        return QLocale().toString( range.lowerValue(), 'f', decimalPlaces ) + " - " + QLocale().toString( range.upperValue(), 'f', decimalPlaces );
+        return QString( QLocale().toString( range.lowerValue(), 'f', decimalPlaces ) + " - " + QLocale().toString( range.upperValue(), 'f', decimalPlaces ) );
       }
       case 2:
         return range.label();
diff --git a/src/plugins/grass/qgsgrassmoduleinput.cpp b/src/plugins/grass/qgsgrassmoduleinput.cpp
index 55e38baacb3..9487c56724c 100644
--- a/src/plugins/grass/qgsgrassmoduleinput.cpp
+++ b/src/plugins/grass/qgsgrassmoduleinput.cpp
@@ -332,7 +332,7 @@ QVariant QgsGrassModuleInputModel::data( const QModelIndex &index, int role ) co
       QString mapset = QStandardItemModel::data( index, QgsGrassModuleInputModel::MapsetRole ).toString();
       if ( mapset != QgsGrass::getDefaultMapset() )
       {
-        data = data.toString() + "@" + mapset;
+        data = QString( data.toString() + "@" + mapset );
       }
     }
   }
diff --git a/src/providers/postgres/qgspostgresprovider.cpp b/src/providers/postgres/qgspostgresprovider.cpp
index c391627ae1d..b5471600355 100644
--- a/src/providers/postgres/qgspostgresprovider.cpp
+++ b/src/providers/postgres/qgspostgresprovider.cpp
@@ -4935,9 +4935,9 @@ QList<QgsRelation> QgsPostgresProvider::discoverRelations( const QgsVectorLayer
     "   FROM pg_constraint c "
     "   WHERE contype = 'f' "
     "     AND c.conrelid::regclass = " +
-    QgsPostgresConn::quotedValue( QgsPostgresConn::quotedIdentifier( mSchemaName ) +
+    QgsPostgresConn::quotedValue( QString( QgsPostgresConn::quotedIdentifier( mSchemaName ) +
                                   '.' +
-                                  QgsPostgresConn::quotedIdentifier( mTableName ) ) +
+                                  QgsPostgresConn::quotedIdentifier( mTableName ) ) ) +
     "::regclass ) "
     "SELECT fk.conname as constraint_name, "
     "       a.attname as column_name, "
diff --git a/src/providers/wfs/qgswfsprovider.cpp b/src/providers/wfs/qgswfsprovider.cpp
index b8a6a8b0992..541e342a079 100644
--- a/src/providers/wfs/qgswfsprovider.cpp
+++ b/src/providers/wfs/qgswfsprovider.cpp
@@ -185,7 +185,7 @@ void QgsWFSProviderSQLFunctionValidator::visit( const QgsSQLStatement::NodeFunct
     for ( const QgsWfsCapabilities::Function &f : constMSpatialPredicatesList )
     {
       if ( n.name().compare( f.name, Qt::CaseInsensitive ) == 0 ||
-           ( "ST_" + n.name() ).compare( f.name, Qt::CaseInsensitive ) == 0 )
+           QString( "ST_" + n.name() ).compare( f.name, Qt::CaseInsensitive ) == 0 )
       {
         foundMatch = true;
       }
diff --git a/src/server/qgsserverogcapihandler.cpp b/src/server/qgsserverogcapihandler.cpp
index 982146ede7a..3880508a4ef 100644
--- a/src/server/qgsserverogcapihandler.cpp
+++ b/src/server/qgsserverogcapihandler.cpp
@@ -287,7 +287,7 @@ void QgsServerOgcApiHandler::htmlDump( const json &data, const QgsServerApiConte
   {
     // Get the template directory and the file name
     QFileInfo pathInfo { path };
-    Environment env { ( pathInfo.dir().path() + QDir::separator() ).toStdString() };
+    Environment env { QString( pathInfo.dir().path() + QDir::separator() ).toStdString() };
 
     // For template debugging:
     env.add_callback( "json_dump", 0, [ = ]( Arguments & )
diff --git a/tests/src/analysis/testqgsprocessing.cpp b/tests/src/analysis/testqgsprocessing.cpp
index 60c16136e99..487e0618d48 100644
--- a/tests/src/analysis/testqgsprocessing.cpp
+++ b/tests/src/analysis/testqgsprocessing.cpp
@@ -2183,7 +2183,7 @@ void TestQgsProcessing::parameters()
 
   QVERIFY( context.temporaryLayerStore()->mapLayers().isEmpty() );
   QString testDataDir = QStringLiteral( TEST_DATA_DIR ) + '/'; //defined in CmakeLists.txt
-  f.setAttribute( 0, testDataDir + "/raster/band1_float32_noct_epsg4326.tif" );
+  f.setAttribute( 0, QString( testDataDir + "/raster/band1_float32_noct_epsg4326.tif" ) );
   context.expressionContext().setFeature( f );
   def->setName( QStringLiteral( "prop" ) );
   QVERIFY( QgsProcessingParameters::parameterAsLayer( def.get(), params, context ) );
@@ -2648,8 +2648,8 @@ void TestQgsProcessing::parameterCrs()
   QCOMPARE( def->valueAsPythonString( "EPSG:12003", context ), QStringLiteral( "'EPSG:12003'" ) );
   QCOMPARE( def->valueAsPythonString( "ProjectCrs", context ), QStringLiteral( "'ProjectCrs'" ) );
   QCOMPARE( def->valueAsPythonString( QStringLiteral( "c:\\test\\new data\\test.dat" ), context ), QStringLiteral( "'c:\\\\test\\\\new data\\\\test.dat'" ) );
-  QCOMPARE( def->valueAsPythonString( raster1, context ), QString( "'" ) + testDataDir + QStringLiteral( "landsat_4326.tif'" ) );
-  QCOMPARE( def->valueAsPythonString( r1->id(), context ), QString( "'" ) + testDataDir + QStringLiteral( "landsat_4326.tif'" ) );
+  QCOMPARE( def->valueAsPythonString( raster1, context ), QString( QString( "'" ) + testDataDir + QStringLiteral( "landsat_4326.tif'" ) ) );
+  QCOMPARE( def->valueAsPythonString( r1->id(), context ), QString( QString( "'" ) + testDataDir + QStringLiteral( "landsat_4326.tif'" ) ) );
   QCOMPARE( def->valueAsPythonString( QVariant::fromValue( QgsProperty::fromExpression( "\"a\"=1" ) ), context ), QStringLiteral( "QgsProperty.fromExpression('\"a\"=1')" ) );
   QCOMPARE( def->valueAsPythonString( "uri='complex' username=\"complex\"", context ), QStringLiteral( "'uri=\\'complex\\' username=\\\"complex\\\"'" ) );
 
@@ -2771,9 +2771,9 @@ void TestQgsProcessing::parameterMapLayer()
   QCOMPARE( QgsProcessingParameters::parameterAsLayer( def.get(), params, context ), v1 );
 
   QCOMPARE( def->valueAsPythonString( QVariant(), context ), QStringLiteral( "None" ) );
-  QCOMPARE( def->valueAsPythonString( raster1, context ), QString( "'" ) + testDataDir + QStringLiteral( "tenbytenraster.asc'" ) );
-  QCOMPARE( def->valueAsPythonString( r1->id(), context ), QString( "'" ) + testDataDir + QStringLiteral( "tenbytenraster.asc'" ) );
-  QCOMPARE( def->valueAsPythonString( QVariant::fromValue( r1 ), context ), QString( "'" ) + testDataDir + QStringLiteral( "tenbytenraster.asc'" ) );
+  QCOMPARE( def->valueAsPythonString( raster1, context ), QString( QString( "'" ) + testDataDir + QStringLiteral( "tenbytenraster.asc'" ) ) );
+  QCOMPARE( def->valueAsPythonString( r1->id(), context ), QString( QString( "'" ) + testDataDir + QStringLiteral( "tenbytenraster.asc'" ) ) );
+  QCOMPARE( def->valueAsPythonString( QVariant::fromValue( r1 ), context ), QString( QString( "'" ) + testDataDir + QStringLiteral( "tenbytenraster.asc'" ) ) );
   QCOMPARE( def->valueAsPythonString( QVariant::fromValue( QgsProperty::fromExpression( "\"a\"=1" ) ), context ), QStringLiteral( "QgsProperty.fromExpression('\"a\"=1')" ) );
   QCOMPARE( def->valueAsPythonString( QStringLiteral( "c:\\test\\new data\\test.dat" ), context ), QStringLiteral( "'c:\\\\test\\\\new data\\\\test.dat'" ) );
 
@@ -2850,10 +2850,10 @@ void TestQgsProcessing::parameterMapLayer()
   QVERIFY( def->checkValueIsAcceptable( QVariant::fromValue( v1 ) ) );
 
   pythonCode = def->asPythonString();
-  QCOMPARE( pythonCode, QStringLiteral( "QgsProcessingParameterMapLayer('optional', '', optional=True, defaultValue='" ) + v1->id() + "')" );
+  QCOMPARE( pythonCode, QString( QStringLiteral( "QgsProcessingParameterMapLayer('optional', '', optional=True, defaultValue='" ) + v1->id() + "')" ) );
 
   code = def->asScriptCode();
-  QCOMPARE( code, QStringLiteral( "##optional=optional layer " ) + v1->id() );
+  QCOMPARE( code, QString( QStringLiteral( "##optional=optional layer " ) + v1->id() ) );
   fromCode.reset( dynamic_cast< QgsProcessingParameterMapLayer * >( QgsProcessingParameters::parameterFromScriptCode( code ) ) );
   QVERIFY( fromCode.get() );
   QCOMPARE( fromCode->name(), def->name() );
@@ -3139,9 +3139,9 @@ void TestQgsProcessing::parameterExtent()
 
   QCOMPARE( def->valueAsPythonString( QVariant(), context ), QStringLiteral( "None" ) );
   QCOMPARE( def->valueAsPythonString( "1,2,3,4", context ), QStringLiteral( "'1,2,3,4'" ) );
-  QCOMPARE( def->valueAsPythonString( r1->id(), context ), QString( "'" ) + testDataDir + QStringLiteral( "landsat_4326.tif'" ) );
-  QCOMPARE( def->valueAsPythonString( QVariant::fromValue( r1 ), context ), QString( "'" ) + testDataDir + QStringLiteral( "landsat_4326.tif'" ) );
-  QCOMPARE( def->valueAsPythonString( raster2, context ), QString( "'" ) + testDataDir + QStringLiteral( "landsat.tif'" ) );
+  QCOMPARE( def->valueAsPythonString( r1->id(), context ), QString( QString( "'" ) + testDataDir + QStringLiteral( "landsat_4326.tif'" ) ) );
+  QCOMPARE( def->valueAsPythonString( QVariant::fromValue( r1 ), context ), QString( QString( "'" ) + testDataDir + QStringLiteral( "landsat_4326.tif'" ) ) );
+  QCOMPARE( def->valueAsPythonString( raster2, context ), QString( QString( "'" ) + testDataDir + QStringLiteral( "landsat.tif'" ) ) );
   QCOMPARE( def->valueAsPythonString( QVariant::fromValue( QgsProperty::fromExpression( "\"a\"=1" ) ), context ), QStringLiteral( "QgsProperty.fromExpression('\"a\"=1')" ) );
   QCOMPARE( def->valueAsPythonString( QgsRectangle( 11, 12, 13, 14 ), context ), QStringLiteral( "'11, 13, 12, 14'" ) );
   QCOMPARE( def->valueAsPythonString( QgsReferencedRectangle( QgsRectangle( 11, 12, 13, 14 ), QgsCoordinateReferenceSystem( "epsg:4326" ) ), context ), QStringLiteral( "'11, 13, 12, 14 [EPSG:4326]'" ) );
@@ -3929,9 +3929,9 @@ void TestQgsProcessing::parameterLayerList()
 
   QCOMPARE( def->valueAsPythonString( QVariant(), context ), QStringLiteral( "None" ) );
   QCOMPARE( def->valueAsPythonString( "layer12312312", context ), QStringLiteral( "'layer12312312'" ) );
-  QCOMPARE( def->valueAsPythonString( QVariant::fromValue( r1 ), context ), QStringLiteral( "['" ) + testDataDir + QStringLiteral( "tenbytenraster.asc']" ) );
-  QCOMPARE( def->valueAsPythonString( r1->id(), context ), QStringLiteral( "['" ) + testDataDir + QStringLiteral( "tenbytenraster.asc']" ) );
-  QCOMPARE( def->valueAsPythonString( QStringList() << r1->id() << raster2, context ), QStringLiteral( "['" ) + testDataDir + QStringLiteral( "tenbytenraster.asc','" ) + testDataDir + QStringLiteral( "landsat.tif']" ) );
+  QCOMPARE( def->valueAsPythonString( QVariant::fromValue( r1 ), context ), QString( QStringLiteral( "['" ) + testDataDir + QStringLiteral( "tenbytenraster.asc']" ) ) );
+  QCOMPARE( def->valueAsPythonString( r1->id(), context ), QString( QStringLiteral( "['" ) + testDataDir + QStringLiteral( "tenbytenraster.asc']" ) ) );
+  QCOMPARE( def->valueAsPythonString( QStringList() << r1->id() << raster2, context ), QString( QStringLiteral( "['" ) + testDataDir + QStringLiteral( "tenbytenraster.asc','" ) + testDataDir + QStringLiteral( "landsat.tif']" ) ) );
   QCOMPARE( def->valueAsPythonString( QVariant::fromValue( QgsProperty::fromExpression( "\"a\"=1" ) ), context ), QStringLiteral( "QgsProperty.fromExpression('\"a\"=1')" ) );
   QCOMPARE( def->valueAsPythonString( "uri='complex' username=\"complex\"", context ), QStringLiteral( "'uri=\\'complex\\' username=\\\"complex\\\"'" ) );
 
@@ -3986,10 +3986,10 @@ void TestQgsProcessing::parameterLayerList()
   QCOMPARE( QgsProcessingParameters::parameterAsLayerList( def.get(), params, context ), QList< QgsMapLayer *>() << r1 );
 
   pythonCode = def->asPythonString();
-  QCOMPARE( pythonCode, QStringLiteral( "QgsProcessingParameterMultipleLayers('optional', '', optional=True, layerType=QgsProcessing.TypeMapLayer, defaultValue='" ) + v1->id() + "')" );
+  QCOMPARE( pythonCode, QString( QStringLiteral( "QgsProcessingParameterMultipleLayers('optional', '', optional=True, layerType=QgsProcessing.TypeMapLayer, defaultValue='" ) + v1->id() + "')" ) );
 
   code = def->asScriptCode();
-  QCOMPARE( code, QStringLiteral( "##optional=optional multiple vector " ) + v1->id() );
+  QCOMPARE( code, QString( QStringLiteral( "##optional=optional multiple vector " ) + v1->id() ) );
   fromCode.reset( dynamic_cast< QgsProcessingParameterMultipleLayers * >( QgsProcessingParameters::parameterFromScriptCode( code ) ) );
   QVERIFY( fromCode.get() );
   QCOMPARE( fromCode->name(), def->name() );
@@ -4008,16 +4008,16 @@ void TestQgsProcessing::parameterLayerList()
   QVERIFY( def->createFileFilter().contains( QStringLiteral( "*.*" ) ) );
 
   pythonCode = def->asPythonString();
-  QCOMPARE( pythonCode, QStringLiteral( "QgsProcessingParameterMultipleLayers('optional', '', optional=True, layerType=QgsProcessing.TypeMapLayer, defaultValue=['" ) + r1->publicSource() + "'])" );
+  QCOMPARE( pythonCode, QString( QStringLiteral( "QgsProcessingParameterMultipleLayers('optional', '', optional=True, layerType=QgsProcessing.TypeMapLayer, defaultValue=['" ) + r1->publicSource() + "'])" ) );
 
   code = def->asScriptCode();
-  QCOMPARE( code, QStringLiteral( "##optional=optional multiple vector " ) + v1->id() + "," + r1->publicSource() );
+  QCOMPARE( code, QString( QStringLiteral( "##optional=optional multiple vector " ) + v1->id() + "," + r1->publicSource() ) );
   fromCode.reset( dynamic_cast< QgsProcessingParameterMultipleLayers * >( QgsProcessingParameters::parameterFromScriptCode( code ) ) );
   QVERIFY( fromCode.get() );
   QCOMPARE( fromCode->name(), def->name() );
   QCOMPARE( fromCode->description(), QStringLiteral( "optional" ) );
   QCOMPARE( fromCode->flags(), def->flags() );
-  QCOMPARE( fromCode->defaultValue().toString(), v1->id() + "," + r1->publicSource() );
+  QCOMPARE( fromCode->defaultValue().toString(), QString( v1->id() + "," + r1->publicSource() ) );
   QCOMPARE( fromCode->layerType(), QgsProcessing::TypeVectorAnyGeometry );
 
   // optional with one default direct layer
@@ -4676,9 +4676,9 @@ void TestQgsProcessing::parameterRasterLayer()
   QVERIFY( !QgsProcessingParameters::parameterAsRasterLayer( def.get(), params, context ) );
 
   QCOMPARE( def->valueAsPythonString( QVariant(), context ), QStringLiteral( "None" ) );
-  QCOMPARE( def->valueAsPythonString( raster1, context ), QString( "'" ) + testDataDir + QStringLiteral( "tenbytenraster.asc'" ) );
-  QCOMPARE( def->valueAsPythonString( r1->id(), context ), QString( "'" ) + testDataDir + QStringLiteral( "tenbytenraster.asc'" ) );
-  QCOMPARE( def->valueAsPythonString( QVariant::fromValue( r1 ), context ), QString( "'" ) + testDataDir + QStringLiteral( "tenbytenraster.asc'" ) );
+  QCOMPARE( def->valueAsPythonString( raster1, context ), QString( QString( "'" ) + testDataDir + QStringLiteral( "tenbytenraster.asc'" ) ) );
+  QCOMPARE( def->valueAsPythonString( r1->id(), context ), QString( QString( "'" ) + testDataDir + QStringLiteral( "tenbytenraster.asc'" ) ) );
+  QCOMPARE( def->valueAsPythonString( QVariant::fromValue( r1 ), context ), QString( QString( "'" ) + testDataDir + QStringLiteral( "tenbytenraster.asc'" ) ) );
   QCOMPARE( def->valueAsPythonString( QVariant::fromValue( QgsProperty::fromExpression( "\"a\"=1" ) ), context ), QStringLiteral( "QgsProperty.fromExpression('\"a\"=1')" ) );
   QCOMPARE( def->valueAsPythonString( QStringLiteral( "c:\\test\\new data\\test.dat" ), context ), QStringLiteral( "'c:\\\\test\\\\new data\\\\test.dat'" ) );
 
@@ -4709,10 +4709,10 @@ void TestQgsProcessing::parameterRasterLayer()
   QCOMPARE( QgsProcessingParameters::parameterAsRasterLayer( def.get(), params, context )->id(), r1->id() );
 
   pythonCode = def->asPythonString();
-  QCOMPARE( pythonCode, QStringLiteral( "QgsProcessingParameterRasterLayer('optional', '', optional=True, defaultValue='" ) + r1->id() + "')" );
+  QCOMPARE( pythonCode, QString( QStringLiteral( "QgsProcessingParameterRasterLayer('optional', '', optional=True, defaultValue='" ) + r1->id() + "')" ) );
 
   code = def->asScriptCode();
-  QCOMPARE( code, QStringLiteral( "##optional=optional raster " ) + r1->id() );
+  QCOMPARE( code, QString( QStringLiteral( "##optional=optional raster " ) + r1->id() ) );
   fromCode.reset( dynamic_cast< QgsProcessingParameterRasterLayer * >( QgsProcessingParameters::parameterFromScriptCode( code ) ) );
   QVERIFY( fromCode.get() );
   QCOMPARE( fromCode->name(), def->name() );
@@ -5635,9 +5635,9 @@ void TestQgsProcessing::parameterVectorLayer()
   QVERIFY( !QgsProcessingParameters::parameterAsVectorLayer( def.get(), params, context ) );
 
   QCOMPARE( def->valueAsPythonString( QVariant(), context ), QStringLiteral( "None" ) );
-  QCOMPARE( def->valueAsPythonString( vector1, context ), QString( "'" ) + testDataDir + QStringLiteral( "multipoint.shp'" ) );
-  QCOMPARE( def->valueAsPythonString( v1->id(), context ), QString( "'" ) + testDataDir + QStringLiteral( "multipoint.shp'" ) );
-  QCOMPARE( def->valueAsPythonString( QVariant::fromValue( v1 ), context ), QString( "'" ) + testDataDir + QStringLiteral( "multipoint.shp'" ) );
+  QCOMPARE( def->valueAsPythonString( vector1, context ), QString( QString( "'" ) + testDataDir + QStringLiteral( "multipoint.shp'" ) ) );
+  QCOMPARE( def->valueAsPythonString( v1->id(), context ), QString( QString( "'" ) + testDataDir + QStringLiteral( "multipoint.shp'" ) ) );
+  QCOMPARE( def->valueAsPythonString( QVariant::fromValue( v1 ), context ), QString( QString( "'" ) + testDataDir + QStringLiteral( "multipoint.shp'" ) ) );
   QCOMPARE( def->valueAsPythonString( QVariant::fromValue( QgsProperty::fromExpression( "\"a\"=1" ) ), context ), QStringLiteral( "QgsProperty.fromExpression('\"a\"=1')" ) );
   QCOMPARE( def->valueAsPythonString( QStringLiteral( "c:\\test\\new data\\test.dat" ), context ), QStringLiteral( "'c:\\\\test\\\\new data\\\\test.dat'" ) );
 
@@ -5677,10 +5677,10 @@ void TestQgsProcessing::parameterVectorLayer()
   QVERIFY( def->checkValueIsAcceptable( QgsProcessingFeatureSourceDefinition( "layer1231123" ) ) );
 
   pythonCode = def->asPythonString();
-  QCOMPARE( pythonCode, QStringLiteral( "QgsProcessingParameterVectorLayer('optional', '', optional=True, defaultValue='" ) + v1->id() + "')" );
+  QCOMPARE( pythonCode, QString( QStringLiteral( "QgsProcessingParameterVectorLayer('optional', '', optional=True, defaultValue='" ) + v1->id() + "')" ) );
 
   code = def->asScriptCode();
-  QCOMPARE( code, QStringLiteral( "##optional=optional vector " ) + v1->id() );
+  QCOMPARE( code, QString( QStringLiteral( "##optional=optional vector " ) + v1->id() ) );
   fromCode.reset( dynamic_cast< QgsProcessingParameterVectorLayer * >( QgsProcessingParameters::parameterFromScriptCode( code ) ) );
   QVERIFY( fromCode.get() );
   QCOMPARE( fromCode->name(), def->name() );
@@ -5764,9 +5764,9 @@ void TestQgsProcessing::parameterMeshLayer()
   QVERIFY( !QgsProcessingParameters::parameterAsVectorLayer( def.get(), params, context ) );
 
   QCOMPARE( def->valueAsPythonString( QVariant(), context ), QStringLiteral( "None" ) );
-  QCOMPARE( def->valueAsPythonString( mesh, context ), QString( "'" ) + testDataDir + QStringLiteral( "mesh/quad_and_triangle.2dm'" ) );
-  QCOMPARE( def->valueAsPythonString( m1->id(), context ), QString( "'" ) + testDataDir + QStringLiteral( "mesh/quad_and_triangle.2dm'" ) );
-  QCOMPARE( def->valueAsPythonString( QVariant::fromValue( m1 ), context ), QString( "'" ) + testDataDir + QStringLiteral( "mesh/quad_and_triangle.2dm'" ) );
+  QCOMPARE( def->valueAsPythonString( mesh, context ), QString( QString( "'" ) + testDataDir + QStringLiteral( "mesh/quad_and_triangle.2dm'" ) ) );
+  QCOMPARE( def->valueAsPythonString( m1->id(), context ), QString( QString( "'" ) + testDataDir + QStringLiteral( "mesh/quad_and_triangle.2dm'" ) ) );
+  QCOMPARE( def->valueAsPythonString( QVariant::fromValue( m1 ), context ), QString( QString( "'" ) + testDataDir + QStringLiteral( "mesh/quad_and_triangle.2dm'" ) ) );
   QCOMPARE( def->valueAsPythonString( QVariant::fromValue( QgsProperty::fromExpression( "\"a\"=1" ) ), context ), QStringLiteral( "QgsProperty.fromExpression('\"a\"=1')" ) );
   QCOMPARE( def->valueAsPythonString( QStringLiteral( "c:\\test\\new data\\test.2dm" ), context ), QStringLiteral( "'c:\\\\test\\\\new data\\\\test.2dm'" ) );
 
@@ -5806,10 +5806,10 @@ void TestQgsProcessing::parameterMeshLayer()
   QVERIFY( def->checkValueIsAcceptable( QgsProcessingFeatureSourceDefinition( "layer1231123" ) ) );
 
   pythonCode = def->asPythonString();
-  QCOMPARE( pythonCode, QStringLiteral( "QgsProcessingParameterMeshLayer('optional', '', optional=True, defaultValue='" ) + m1->id() + "')" );
+  QCOMPARE( pythonCode, QString( QStringLiteral( "QgsProcessingParameterMeshLayer('optional', '', optional=True, defaultValue='" ) + m1->id() + "')" ) );
 
   code = def->asScriptCode();
-  QCOMPARE( code, QStringLiteral( "##optional=optional mesh " ) + m1->id() );
+  QCOMPARE( code, QString( QStringLiteral( "##optional=optional mesh " ) + m1->id() ) );
   fromCode.reset( dynamic_cast< QgsProcessingParameterMeshLayer * >( QgsProcessingParameters::parameterFromScriptCode( code ) ) );
   QVERIFY( fromCode.get() );
   QCOMPARE( fromCode->name(), def->name() );
@@ -5977,9 +5977,9 @@ void TestQgsProcessing::parameterFeatureSource()
   QVERIFY( def->checkValueIsAcceptable( QgsProcessingFeatureSourceDefinition( "layer1231123" ) ) );
 
   pythonCode = def->asPythonString();
-  QCOMPARE( pythonCode, QStringLiteral( "QgsProcessingParameterFeatureSource('optional', '', optional=True, types=[QgsProcessing.TypeVectorAnyGeometry], defaultValue='" ) + v1->id() + "')" );
+  QCOMPARE( pythonCode, QString( QStringLiteral( "QgsProcessingParameterFeatureSource('optional', '', optional=True, types=[QgsProcessing.TypeVectorAnyGeometry], defaultValue='" ) + v1->id() + "')" ) );
   code = def->asScriptCode();
-  QCOMPARE( code, QStringLiteral( "##optional=optional source " ) + v1->id() );
+  QCOMPARE( code, QString( QStringLiteral( "##optional=optional source " ) + v1->id() ) );
   fromCode.reset( dynamic_cast< QgsProcessingParameterFeatureSource * >( QgsProcessingParameters::parameterFromScriptCode( code ) ) );
   QVERIFY( fromCode.get() );
   QCOMPARE( fromCode->name(), def->name() );
@@ -8643,13 +8643,13 @@ void TestQgsProcessing::modelScope()
   pc.setProject( &p );
   p.setFileName( TEST_DATA_DIR + QStringLiteral( "/test_file.qgs" ) );
   scope.reset( QgsExpressionContextUtils::processingModelAlgorithmScope( &alg, params, pc ) );
-  QCOMPARE( scope->variable( QStringLiteral( "model_path" ) ).toString(), QStringLiteral( TEST_DATA_DIR ) + QStringLiteral( "/test_file.qgs" ) );
+  QCOMPARE( scope->variable( QStringLiteral( "model_path" ) ).toString(), QString( QStringLiteral( TEST_DATA_DIR ) + QStringLiteral( "/test_file.qgs" ) ) );
   QCOMPARE( scope->variable( QStringLiteral( "model_folder" ) ).toString(), QStringLiteral( TEST_DATA_DIR ) );
 
   alg.setSourceFilePath( TEST_DATA_DIR + QStringLiteral( "/processing/my_model.model3" ) );
   scope.reset( QgsExpressionContextUtils::processingModelAlgorithmScope( &alg, params, pc ) );
-  QCOMPARE( scope->variable( QStringLiteral( "model_path" ) ).toString(), QStringLiteral( TEST_DATA_DIR ) + QStringLiteral( "/processing/my_model.model3" ) );
-  QCOMPARE( scope->variable( QStringLiteral( "model_folder" ) ).toString(), QStringLiteral( TEST_DATA_DIR ) + QStringLiteral( "/processing" ) );
+  QCOMPARE( scope->variable( QStringLiteral( "model_path" ) ).toString(), QString( QStringLiteral( TEST_DATA_DIR ) + QStringLiteral( "/processing/my_model.model3" ) ) );
+  QCOMPARE( scope->variable( QStringLiteral( "model_folder" ) ).toString(), QString( QStringLiteral( TEST_DATA_DIR ) + QStringLiteral( "/processing" ) ) );
 
   QgsExpressionContext ctx = alg.createExpressionContext( QVariantMap(), pc );
   QVERIFY( scope->hasVariable( QStringLiteral( "model_path" ) ) );
@@ -10536,7 +10536,7 @@ void TestQgsProcessing::modelValidate()
   QCOMPARE( errors.at( 0 ), QStringLiteral( "Model input <i>cc</i> used for parameter <i>INPUT</i> does not exist" ) );
 
   goodSource.setSource( QgsProcessingModelChildParameterSource::StaticValue );
-  goodSource.setStaticValue( QStringLiteral( TEST_DATA_DIR ) + "/polys.shp" );
+  goodSource.setStaticValue( QString( QStringLiteral( TEST_DATA_DIR ) + "/polys.shp" ) );
   m.childAlgorithm( QStringLiteral( "cx1" ) ).addParameterSources( QStringLiteral( "INPUT" ), QList< QgsProcessingModelChildParameterSource >() << goodSource );
 
   QVERIFY( m.validateChildAlgorithm( QStringLiteral( "cx1" ), errors ) );
@@ -10836,7 +10836,7 @@ void TestQgsProcessing::convertCompatible()
   QVERIFY( gpkgLayer->isValid() );
   out = QgsProcessingUtils::convertToCompatibleFormat( gpkgLayer.get(), false, QStringLiteral( "test" ), QStringList() << "gpkg" << "shp", QString( "shp" ), context, &feedback );
   // layer must be translated -- we do not know if external tool can handle picking the correct layer automatically
-  QCOMPARE( out, testDataDir + QStringLiteral( "points_gpkg.gpkg" ) );
+  QCOMPARE( out, QString( testDataDir + QStringLiteral( "points_gpkg.gpkg" ) ) );
   gpkgPath = testDataDir + "points_gpkg.gpkg|layername=points_small";
   gpkgLayer = qgis::make_unique< QgsVectorLayer >( gpkgPath, "vl" );
   QVERIFY( gpkgLayer->isValid() );
@@ -10849,13 +10849,13 @@ void TestQgsProcessing::convertCompatible()
   QVERIFY( gpkgLayer->isValid() );
   out = QgsProcessingUtils::convertToCompatibleFormatAndLayerName( gpkgLayer.get(), false, QStringLiteral( "test" ), QStringList() << "gpkg" << "shp", QString( "shp" ), context, &feedback, layerName );
   // layer SHOULD NOT be translated -- in this case we know that the external tool can handle specifying the correct layer
-  QCOMPARE( out, testDataDir + QStringLiteral( "points_gpkg.gpkg" ) );
+  QCOMPARE( out, QString( testDataDir + QStringLiteral( "points_gpkg.gpkg" ) ) );
   QCOMPARE( layerName, QStringLiteral( "points_gpkg" ) );
   gpkgPath = testDataDir + "points_gpkg.gpkg|layername=points_small";
   gpkgLayer = qgis::make_unique< QgsVectorLayer >( gpkgPath, "vl" );
   QVERIFY( gpkgLayer->isValid() );
   out = QgsProcessingUtils::convertToCompatibleFormatAndLayerName( gpkgLayer.get(), false, QStringLiteral( "test" ), QStringList() << "gpkg" << "shp", QString( "shp" ), context, &feedback, layerName );
-  QCOMPARE( out, testDataDir + QStringLiteral( "points_gpkg.gpkg" ) );
+  QCOMPARE( out, QString( testDataDir + QStringLiteral( "points_gpkg.gpkg" ) ) );
   QCOMPARE( layerName, QStringLiteral( "points_small" ) );
 
   // also test evaluating parameter to compatible format
@@ -10863,9 +10863,9 @@ void TestQgsProcessing::convertCompatible()
   QVariantMap params;
   params.insert( QStringLiteral( "source" ), QgsProcessingFeatureSourceDefinition( layer->id(), false ) );
   out = QgsProcessingParameters::parameterAsCompatibleSourceLayerPath( def.get(), params, context, QStringList() << "shp", QString( "shp" ), &feedback );
-  QCOMPARE( out, testDataDir + "points.shp" );
+  QCOMPARE( out, QString( testDataDir + "points.shp" ) );
   out = QgsProcessingParameters::parameterAsCompatibleSourceLayerPathAndLayerName( def.get(), params, context, QStringList() << "shp", QString( "shp" ), &feedback, &layerName );
-  QCOMPARE( out, testDataDir + "points.shp" );
+  QCOMPARE( out, QString( testDataDir + "points.shp" ) );
   QCOMPARE( layerName, QString() );
 
   // incompatible format, will be converted
@@ -10882,9 +10882,9 @@ void TestQgsProcessing::convertCompatible()
   // layer as input
   params.insert( QStringLiteral( "source" ), QVariant::fromValue( layer ) );
   out = QgsProcessingParameters::parameterAsCompatibleSourceLayerPath( def.get(), params, context, QStringList() << "shp", QString( "shp" ), &feedback );
-  QCOMPARE( out, testDataDir + "points.shp" );
+  QCOMPARE( out, QString( testDataDir + "points.shp" ) );
   out = QgsProcessingParameters::parameterAsCompatibleSourceLayerPathAndLayerName( def.get(), params, context, QStringList() << "shp", QString( "shp" ), &feedback, &layerName );
-  QCOMPARE( out, testDataDir + "points.shp" );
+  QCOMPARE( out, QString( testDataDir + "points.shp" ) );
   QCOMPARE( layerName, QString() );
 
   // incompatible format, will be converted
@@ -10935,9 +10935,9 @@ void TestQgsProcessing::convertCompatible()
   def.reset( new QgsProcessingParameterFeatureSource( QStringLiteral( "source" ), QString(), QList<int>(), QVariant::fromValue( layer ) ) );
   params.remove( QStringLiteral( "source" ) );
   out = QgsProcessingParameters::parameterAsCompatibleSourceLayerPath( def.get(), params, context, QStringList() << "shp", QString( "shp" ), &feedback );
-  QCOMPARE( out, testDataDir + "points.shp" );
+  QCOMPARE( out, QString( testDataDir + "points.shp" ) );
   out = QgsProcessingParameters::parameterAsCompatibleSourceLayerPathAndLayerName( def.get(), params, context, QStringList() << "shp", QString( "shp" ), &feedback, &layerName );
-  QCOMPARE( out, testDataDir + "points.shp" );
+  QCOMPARE( out, QString( testDataDir + "points.shp" ) );
   QCOMPARE( layerName, QString() );
 
   // geopackage with layer
@@ -10947,7 +10947,7 @@ void TestQgsProcessing::convertCompatible()
   params.insert( QStringLiteral( "source" ), QVariant::fromValue( gpkgLayer.get() ) );
   out = QgsProcessingParameters::parameterAsCompatibleSourceLayerPath( def.get(), params, context, QStringList() << "gpkg" << "shp", QString( "shp" ), &feedback );
   // layer must be translated -- we do not know if external tool can handle picking the correct layer automatically
-  QCOMPARE( out, testDataDir + QStringLiteral( "points_gpkg.gpkg" ) );
+  QCOMPARE( out, QString( testDataDir + QStringLiteral( "points_gpkg.gpkg" ) ) );
   gpkgPath = testDataDir + "points_gpkg.gpkg|layername=points_small";
   gpkgLayer = qgis::make_unique< QgsVectorLayer >( gpkgPath, "vl" );
   QVERIFY( gpkgLayer->isValid() );
@@ -10962,22 +10962,22 @@ void TestQgsProcessing::convertCompatible()
   params.insert( QStringLiteral( "source" ), QVariant::fromValue( gpkgLayer.get() ) );
   out = QgsProcessingParameters::parameterAsCompatibleSourceLayerPathAndLayerName( def.get(), params, context, QStringList() << "gpkg" << "shp", QString( "shp" ), &feedback, &layerName );
   // layer SHOULD NOT be translated -- in this case we know that the external tool can handle specifying the correct layer
-  QCOMPARE( out, testDataDir + QStringLiteral( "points_gpkg.gpkg" ) );
+  QCOMPARE( out, QString( testDataDir + QStringLiteral( "points_gpkg.gpkg" ) ) );
   QCOMPARE( layerName, QStringLiteral( "points_gpkg" ) );
   gpkgPath = testDataDir + "points_gpkg.gpkg|layername=points_small";
   gpkgLayer = qgis::make_unique< QgsVectorLayer >( gpkgPath, "vl" );
   QVERIFY( gpkgLayer->isValid() );
   params.insert( QStringLiteral( "source" ), QVariant::fromValue( gpkgLayer.get() ) );
   out = QgsProcessingParameters::parameterAsCompatibleSourceLayerPathAndLayerName( def.get(), params, context, QStringList() << "gpkg" << "shp", QString( "shp" ), &feedback, &layerName );
-  QCOMPARE( out, testDataDir + QStringLiteral( "points_gpkg.gpkg" ) );
+  QCOMPARE( out, QString( testDataDir + QStringLiteral( "points_gpkg.gpkg" ) ) );
   QCOMPARE( layerName, QStringLiteral( "points_small" ) );
 
   // output layer as input - e.g. from a previous model child
   params.insert( QStringLiteral( "source" ), QgsProcessingOutputLayerDefinition( layer->id() ) );
   out = QgsProcessingParameters::parameterAsCompatibleSourceLayerPath( def.get(), params, context, QStringList() << "shp", QString( "shp" ), &feedback );
-  QCOMPARE( out, testDataDir + "points.shp" );
+  QCOMPARE( out, QString( testDataDir + "points.shp" ) );
   out = QgsProcessingParameters::parameterAsCompatibleSourceLayerPathAndLayerName( def.get(), params, context, QStringList() << "shp", QString( "shp" ), &feedback, &layerName );
-  QCOMPARE( out, testDataDir + "points.shp" );
+  QCOMPARE( out, QString( testDataDir + "points.shp" ) );
   QCOMPARE( layerName, QString() );
 }
 
diff --git a/tests/src/analysis/testqgsprocessingalgs.cpp b/tests/src/analysis/testqgsprocessingalgs.cpp
index a8555a03308..dff5ccd4482 100644
--- a/tests/src/analysis/testqgsprocessingalgs.cpp
+++ b/tests/src/analysis/testqgsprocessingalgs.cpp
@@ -261,7 +261,7 @@ void TestQgsProcessingAlgs::saveFeaturesAlg()
   QString dataDir( TEST_DATA_DIR ); //defined in CmakeLists.txt
 
   QVariantMap parameters;
-  parameters.insert( QStringLiteral( "INPUT" ), dataDir + "/points.shp" );
+  parameters.insert( QStringLiteral( "INPUT" ), QString( dataDir + "/points.shp" ) );
   parameters.insert( QStringLiteral( "LAYER_NAME" ), layerName );
   parameters.insert( QStringLiteral( "LAYER_OPTIONS" ), QStringLiteral( "COORDINATE_PRECISION=1" ) );
   parameters.insert( QStringLiteral( "OUTPUT" ), outputGeoJson );
@@ -1667,7 +1667,7 @@ void TestQgsProcessingAlgs::fillNoData()
 
   QVariantMap parameters;
 
-  parameters.insert( QStringLiteral( "INPUT" ), myDataPath + inputRaster );
+  parameters.insert( QStringLiteral( "INPUT" ), QString( myDataPath + inputRaster ) );
   parameters.insert( QStringLiteral( "BAND" ), inputBand );
   parameters.insert( QStringLiteral( "FILL_VALUE" ), fillValue );
   parameters.insert( QStringLiteral( "OUTPUT" ), QgsProcessing::TEMPORARY_OUTPUT );
@@ -2337,7 +2337,7 @@ void TestQgsProcessingAlgs::cellStatistics()
   parameters.insert( QStringLiteral( "INPUT" ), inputDatasetPaths );
   parameters.insert( QStringLiteral( "STATISTIC" ), statistic );
   parameters.insert( QStringLiteral( "IGNORE_NODATA" ), ignoreNoData );
-  parameters.insert( QStringLiteral( "REFERENCE_LAYER" ), myDataPath + referenceLayer );
+  parameters.insert( QStringLiteral( "REFERENCE_LAYER" ), QString( myDataPath + referenceLayer ) );
   parameters.insert( QStringLiteral( "OUTPUT" ), QgsProcessing::TEMPORARY_OUTPUT );
 
   //prepare expectedRaster
@@ -2578,7 +2578,7 @@ void TestQgsProcessingAlgs::rasterFrequencyByComparisonOperator()
 
   QVariantMap parameters;
 
-  parameters.insert( QStringLiteral( "INPUT_VALUE_RASTER" ), myDataPath + inputValueRaster );
+  parameters.insert( QStringLiteral( "INPUT_VALUE_RASTER" ), QString( myDataPath + inputValueRaster ) );
   parameters.insert( QStringLiteral( "INPUT_VALUE_RASTER_BAND" ), inputValueRasterBand );
   parameters.insert( QStringLiteral( "INPUT_RASTERS" ), inputDatasetPaths );
   parameters.insert( QStringLiteral( "IGNORE_NODATA" ), ignoreNoData );
@@ -2724,7 +2724,7 @@ void TestQgsProcessingAlgs::rasterLocalPosition()
   QVariantMap parameters;
 
   parameters.insert( QStringLiteral( "INPUT_RASTERS" ), inputDatasetPaths );
-  parameters.insert( QStringLiteral( "REFERENCE_LAYER" ), myDataPath + referenceRaster );
+  parameters.insert( QStringLiteral( "REFERENCE_LAYER" ), QString( myDataPath + referenceRaster ) );
   parameters.insert( QStringLiteral( "IGNORE_NODATA" ), ignoreNoData );
   parameters.insert( QStringLiteral( "OUTPUT" ), QgsProcessing::TEMPORARY_OUTPUT );
 
@@ -2946,7 +2946,7 @@ void TestQgsProcessingAlgs::roundRasterValues()
 
   QVariantMap parameters;
 
-  parameters.insert( QStringLiteral( "INPUT" ), myDataPath + inputRaster );
+  parameters.insert( QStringLiteral( "INPUT" ), QString( myDataPath + inputRaster ) );
   parameters.insert( QStringLiteral( "BAND" ), inputBand );
   parameters.insert( QStringLiteral( "ROUNDING_DIRECTION" ), roundingDirection );
   parameters.insert( QStringLiteral( "DECIMAL_PLACES" ), decimals );
@@ -3761,21 +3761,21 @@ void TestQgsProcessingAlgs::shapefileEncoding()
   QVariantMap results;
   results = alg->run( parameters, *context, &feedback, &ok );
 
-  parameters.insert( QStringLiteral( "INPUT" ), QStringLiteral( TEST_DATA_DIR ) + "/shapefile/iso-8859-1.shp" );
+  parameters.insert( QStringLiteral( "INPUT" ), QString( QStringLiteral( TEST_DATA_DIR ) + "/shapefile/iso-8859-1.shp" ) );
   results = alg->run( parameters, *context, &feedback, &ok );
   QVERIFY( ok );
   QCOMPARE( results.value( QStringLiteral( "ENCODING" ) ).toString(), QStringLiteral( "ISO-8859-1" ) );
   QCOMPARE( results.value( QStringLiteral( "CPG_ENCODING" ) ).toString(), QStringLiteral( "ISO-8859-1" ) );
   QCOMPARE( results.value( QStringLiteral( "LDID_ENCODING" ) ).toString(), QString() );
 
-  parameters.insert( QStringLiteral( "INPUT" ), QStringLiteral( TEST_DATA_DIR ) + "/shapefile/windows-1252_ldid.shp" );
+  parameters.insert( QStringLiteral( "INPUT" ), QString( QStringLiteral( TEST_DATA_DIR ) + "/shapefile/windows-1252_ldid.shp" ) );
   results = alg->run( parameters, *context, &feedback, &ok );
   QVERIFY( ok );
   QCOMPARE( results.value( QStringLiteral( "ENCODING" ) ).toString(), QStringLiteral( "CP1252" ) );
   QCOMPARE( results.value( QStringLiteral( "CPG_ENCODING" ) ).toString(), QString() );
   QCOMPARE( results.value( QStringLiteral( "LDID_ENCODING" ) ).toString(), QStringLiteral( "CP1252" ) );
 
-  parameters.insert( QStringLiteral( "INPUT" ), QStringLiteral( TEST_DATA_DIR ) + "/shapefile/system_encoding.shp" );
+  parameters.insert( QStringLiteral( "INPUT" ), QString( QStringLiteral( TEST_DATA_DIR ) + "/shapefile/system_encoding.shp" ) );
   results = alg->run( parameters, *context, &feedback, &ok );
   QVERIFY( ok );
   QCOMPARE( results.value( QStringLiteral( "ENCODING" ) ).toString(), QString() );
@@ -4722,7 +4722,7 @@ void TestQgsProcessingAlgs::exportAtlasLayoutPng()
   QVariantMap parameters;
   parameters.insert( QStringLiteral( "LAYOUT" ), QStringLiteral( "my layout" ) );
   parameters.insert( QStringLiteral( "COVERAGE_LAYER" ), QVariant::fromValue( polygonLayer ) );
-  parameters.insert( QStringLiteral( "FOLDER" ), QDir::tempPath() + "/my_atlas" );
+  parameters.insert( QStringLiteral( "FOLDER" ), QString( QDir::tempPath() + "/my_atlas" ) );
   parameters.insert( QStringLiteral( "FILENAME_EXPRESSION" ), QStringLiteral( "'export_'||@atlas_featurenumber" ) );
   parameters.insert( QStringLiteral( "DPI" ), 96 );
 
@@ -4774,7 +4774,7 @@ void TestQgsProcessingAlgs::tinMeshCreation()
 
   QVariantMap parameters;
   parameters.insert( QStringLiteral( "SOURCE_DATA" ), inputLayers );
-  parameters.insert( QStringLiteral( "OUTPUT_MESH" ), QDir::tempPath() + "/meshLayer.2dm" );
+  parameters.insert( QStringLiteral( "OUTPUT_MESH" ), QString( QDir::tempPath() + "/meshLayer.2dm" ) );
   parameters.insert( QStringLiteral( "MESH_FORMAT" ), 0 );
 
   std::unique_ptr< QgsProcessingContext > context = qgis::make_unique< QgsProcessingContext >();
diff --git a/tests/src/core/testqgslayoutmapgrid.cpp b/tests/src/core/testqgslayoutmapgrid.cpp
index 31e03721e4a..f438548eb59 100644
--- a/tests/src/core/testqgslayoutmapgrid.cpp
+++ b/tests/src/core/testqgslayoutmapgrid.cpp
@@ -1225,23 +1225,23 @@ void TestQgsLayoutMapGrid::annotationFormats()
   QgsExpressionContext expressionContext = gridGeographic.createExpressionContext();
 
   //normal e/w
-  QCOMPARE( gridGeographic.gridAnnotationString( 90, QgsLayoutItemMapGrid::Longitude, expressionContext ), QString( "90.0" ) + QChar( 176 ) + QString( "E" ) );
+  QCOMPARE( gridGeographic.gridAnnotationString( 90, QgsLayoutItemMapGrid::Longitude, expressionContext ), QString( "90.0°E" ) );
   QCOMPARE( gridProjected.gridAnnotationString( 90, QgsLayoutItemMapGrid::Longitude, expressionContext ), QString( "90.0E" ) );
 
   //0 degrees
-  QCOMPARE( gridGeographic.gridAnnotationString( 0, QgsLayoutItemMapGrid::Longitude, expressionContext ), QString( "0.0" ) + QChar( 176 ) );
+  QCOMPARE( gridGeographic.gridAnnotationString( 0, QgsLayoutItemMapGrid::Longitude, expressionContext ), QString( "0.0°" ) );
   QCOMPARE( gridProjected.gridAnnotationString( 0, QgsLayoutItemMapGrid::Longitude, expressionContext ), QString( "0.0E" ) );
 
   //180 degrees
-  QCOMPARE( gridGeographic.gridAnnotationString( 180, QgsLayoutItemMapGrid::Longitude, expressionContext ), QString( "180.0" ) + QChar( 176 ) );
+  QCOMPARE( gridGeographic.gridAnnotationString( 180, QgsLayoutItemMapGrid::Longitude, expressionContext ), QString( "180.0°" ) );
   QCOMPARE( gridProjected.gridAnnotationString( 180, QgsLayoutItemMapGrid::Longitude, expressionContext ), QString( "180.0E" ) );
 
   //normal n/s
-  QCOMPARE( gridGeographic.gridAnnotationString( 45, QgsLayoutItemMapGrid::Latitude, expressionContext ), QString( "45.0" ) + QChar( 176 ) + QString( "N" ) );
+  QCOMPARE( gridGeographic.gridAnnotationString( 45, QgsLayoutItemMapGrid::Latitude, expressionContext ), QString( "45.0°N" ) );
   QCOMPARE( gridProjected.gridAnnotationString( 45, QgsLayoutItemMapGrid::Latitude, expressionContext ), QString( "45.0N" ) );
 
   //0 north/south
-  QCOMPARE( gridGeographic.gridAnnotationString( 0, QgsLayoutItemMapGrid::Latitude, expressionContext ), QString( "0.0" ) + QChar( 176 ) );
+  QCOMPARE( gridGeographic.gridAnnotationString( 0, QgsLayoutItemMapGrid::Latitude, expressionContext ), QString( "0.0°" ) );
   QCOMPARE( gridProjected.gridAnnotationString( 0, QgsLayoutItemMapGrid::Latitude, expressionContext ), QString( "0.0N" ) );
 
   //Custom format annotations
diff --git a/tests/src/core/testqgsproject.cpp b/tests/src/core/testqgsproject.cpp
index fc18d1b3c69..9b82c5c8109 100644
--- a/tests/src/core/testqgsproject.cpp
+++ b/tests/src/core/testqgsproject.cpp
@@ -150,7 +150,7 @@ void TestQgsProject::testPathResolver()
   QVERIFY( testFile.open( QIODevice::WriteOnly | QIODevice::Text ) );
   testFile.close();
   QVERIFY( QFile::exists( fi.path() + QStringLiteral( "/file1.txt" ) ) );
-  QCOMPARE( tempRel.readPath( "file1.txt" ), fi.path() + QStringLiteral( "/file1.txt" ) );
+  QCOMPARE( tempRel.readPath( "file1.txt" ), QString( fi.path() + QStringLiteral( "/file1.txt" ) ) );
 
   QgsPathResolver resolverAbs;
   QCOMPARE( resolverAbs.writePath( "/home/qgis/file1.txt" ), QString( "/home/qgis/file1.txt" ) );
@@ -269,7 +269,7 @@ void TestQgsProject::testPathResolverSvg()
   project.write( projectFilename );
 
   // make sure the path resolver works with relative paths (enabled by default)
-  QCOMPARE( project.pathResolver().readPath( "./a.txt" ), dirPath + "/a.txt" );
+  QCOMPARE( project.pathResolver().readPath( "./a.txt" ), QString( dirPath + "/a.txt" ) );
   QCOMPARE( project.pathResolver().writePath( dirPath + "/a.txt" ), QString( "./a.txt" ) );
 
   // check that the saved paths are relative
diff --git a/tests/src/core/testqgsziputils.cpp b/tests/src/core/testqgsziputils.cpp
index 11fad10d1e7..f17daa29d80 100644
--- a/tests/src/core/testqgsziputils.cpp
+++ b/tests/src/core/testqgsziputils.cpp
@@ -113,7 +113,7 @@ void TestQgsZipUtils::testZip()
   QVERIFY( QgsZipUtils::zip( zipDirPath + "/special_zip æì.zip", QStringList() << txtFile ) );
   QVERIFY( QgsZipUtils::unzip( zipDirPath + "/special_zip æì.zip", zipDirPath, files ) );
   QCOMPARE( files.count(), 1 );
-  QCOMPARE( files.at( 0 ), zipDirPath + "/aæýì.txt" );
+  QCOMPARE( files.at( 0 ), QString( zipDirPath + "/aæýì.txt" ) );
   QVERIFY( QFile::exists( zipDirPath + "/aæýì.txt" ) );
 }
 
diff --git a/tests/src/gui/testprocessinggui.cpp b/tests/src/gui/testprocessinggui.cpp
index a7e700f9cd3..13fdd83ad19 100644
--- a/tests/src/gui/testprocessinggui.cpp
+++ b/tests/src/gui/testprocessinggui.cpp
@@ -1144,10 +1144,10 @@ void TestProcessingGui::testFileWrapper()
     QWidget *w = wrapper.createWrappedWidget( context );
 
     QSignalSpy spy( &wrapper, &QgsProcessingFileWidgetWrapper::widgetValueHasChanged );
-    wrapper.setWidgetValue( TEST_DATA_DIR + QStringLiteral( "/points.shp" ), context );
+    wrapper.setWidgetValue( QString( TEST_DATA_DIR + QStringLiteral( "/points.shp" ) ), context );
     QCOMPARE( spy.count(), 1 );
-    QCOMPARE( wrapper.widgetValue().toString(),  TEST_DATA_DIR + QStringLiteral( "/points.shp" ) );
-    QCOMPARE( static_cast< QgsFileWidget * >( wrapper.wrappedWidget() )->filePath(),  TEST_DATA_DIR + QStringLiteral( "/points.shp" ) );
+    QCOMPARE( wrapper.widgetValue().toString(), QString( TEST_DATA_DIR + QStringLiteral( "/points.shp" ) ) );
+    QCOMPARE( static_cast< QgsFileWidget * >( wrapper.wrappedWidget() )->filePath(), QString( TEST_DATA_DIR + QStringLiteral( "/points.shp" ) ) );
     QCOMPARE( static_cast< QgsFileWidget * >( wrapper.wrappedWidget() )->filter(), QStringLiteral( "All files (*.*)" ) );
     QCOMPARE( static_cast< QgsFileWidget * >( wrapper.wrappedWidget() )->storageMode(),  QgsFileWidget::GetFile );
     wrapper.setWidgetValue( QString(), context );
@@ -3213,27 +3213,27 @@ void TestProcessingGui::testMultipleFileSelectionDialog()
   QCOMPARE( dlg->selectedOptions().size(), 1 );
   QCOMPARE( dlg->selectedOptions().at( 0 ).toString(), raster->source() );
   // existing value using full layer path not matching a project layer should work
-  dlg = qgis::make_unique< QgsProcessingMultipleInputPanelWidget >( param.get(), QVariantList() << raster->source() << QStringLiteral( TEST_DATA_DIR ) + "/landsat.tif", QList<QgsProcessingModelChildParameterSource >() );
+  dlg = qgis::make_unique< QgsProcessingMultipleInputPanelWidget >( param.get(), QVariantList() << raster->source() << QString( QStringLiteral( TEST_DATA_DIR ) + "/landsat.tif" ), QList<QgsProcessingModelChildParameterSource >() );
   dlg->setProject( QgsProject::instance() );
   QCOMPARE( dlg->mModel->rowCount(), 2 );
   QCOMPARE( dlg->mModel->data( dlg->mModel->index( 0, 0 ) ).toString(), QStringLiteral( "raster [EPSG:4326]" ) );
   QCOMPARE( dlg->mModel->data( dlg->mModel->index( 0, 0 ), Qt::UserRole ).toString(), raster->source() );
-  QCOMPARE( dlg->mModel->data( dlg->mModel->index( 1, 0 ) ).toString(), QStringLiteral( TEST_DATA_DIR ) + "/landsat.tif" );
-  QCOMPARE( dlg->mModel->data( dlg->mModel->index( 1, 0 ), Qt::UserRole ).toString(), QStringLiteral( TEST_DATA_DIR ) + "/landsat.tif" );
+  QCOMPARE( dlg->mModel->data( dlg->mModel->index( 1, 0 ) ).toString(), QString( QStringLiteral( TEST_DATA_DIR ) + "/landsat.tif" ) );
+  QCOMPARE( dlg->mModel->data( dlg->mModel->index( 1, 0 ), Qt::UserRole ).toString(), QString( QStringLiteral( TEST_DATA_DIR ) + "/landsat.tif" ) );
   QCOMPARE( dlg->selectedOptions().size(), 2 );
   QCOMPARE( dlg->selectedOptions().at( 0 ).toString(), raster->source() );
-  QCOMPARE( dlg->selectedOptions().at( 1 ).toString(), QStringLiteral( TEST_DATA_DIR ) + "/landsat.tif" );
+  QCOMPARE( dlg->selectedOptions().at( 1 ).toString(), QString( QStringLiteral( TEST_DATA_DIR ) + "/landsat.tif" ) );
 
   // should remember layer order
-  dlg = qgis::make_unique< QgsProcessingMultipleInputPanelWidget >( param.get(), QVariantList()  << QStringLiteral( TEST_DATA_DIR ) + "/landsat.tif" << raster->source(), QList<QgsProcessingModelChildParameterSource >() );
+  dlg = qgis::make_unique< QgsProcessingMultipleInputPanelWidget >( param.get(), QVariantList()  << QString( QStringLiteral( TEST_DATA_DIR ) + "/landsat.tif" ) << raster->source(), QList<QgsProcessingModelChildParameterSource >() );
   dlg->setProject( QgsProject::instance() );
   QCOMPARE( dlg->mModel->rowCount(), 2 );
-  QCOMPARE( dlg->mModel->data( dlg->mModel->index( 0, 0 ) ).toString(), QStringLiteral( TEST_DATA_DIR ) + "/landsat.tif" );
-  QCOMPARE( dlg->mModel->data( dlg->mModel->index( 0, 0 ), Qt::UserRole ).toString(), QStringLiteral( TEST_DATA_DIR ) + "/landsat.tif" );
+  QCOMPARE( dlg->mModel->data( dlg->mModel->index( 0, 0 ) ).toString(), QString( QStringLiteral( TEST_DATA_DIR ) + "/landsat.tif" ) );
+  QCOMPARE( dlg->mModel->data( dlg->mModel->index( 0, 0 ), Qt::UserRole ).toString(), QString( QStringLiteral( TEST_DATA_DIR ) + "/landsat.tif" ) );
   QCOMPARE( dlg->mModel->data( dlg->mModel->index( 1, 0 ) ).toString(), QStringLiteral( "raster [EPSG:4326]" ) );
   QCOMPARE( dlg->mModel->data( dlg->mModel->index( 1, 0 ), Qt::UserRole ).toString(), raster->source() );
   QCOMPARE( dlg->selectedOptions().size(), 2 );
-  QCOMPARE( dlg->selectedOptions().at( 0 ).toString(), QStringLiteral( TEST_DATA_DIR ) + "/landsat.tif" );
+  QCOMPARE( dlg->selectedOptions().at( 0 ).toString(), QString( QStringLiteral( TEST_DATA_DIR ) + "/landsat.tif" ) );
   QCOMPARE( dlg->selectedOptions().at( 1 ).toString(), raster->source() );
 
   // mesh
@@ -7866,7 +7866,7 @@ void TestProcessingGui::testOutputDefinitionWidget()
   v = panel.value();
   QVERIFY( v.canConvert< QgsProcessingOutputLayerDefinition>() );
   QCOMPARE( v.value< QgsProcessingOutputLayerDefinition>().createOptions.value( QStringLiteral( "fileEncoding" ) ).toString(), QStringLiteral( "utf8" ) );
-  QCOMPARE( v.value< QgsProcessingOutputLayerDefinition>().sink.staticValue().toString(), TEST_DATA_DIR + QStringLiteral( "/test.shp" ) );
+  QCOMPARE( v.value< QgsProcessingOutputLayerDefinition>().sink.staticValue().toString(), QString( TEST_DATA_DIR + QStringLiteral( "/test.shp" ) ) );
 
   // optional, test skipping
   sink.setFlags( sink.flags() | QgsProcessingParameterDefinition::FlagOptional );
@@ -8041,7 +8041,7 @@ void TestProcessingGui::testOutputDefinitionWidgetVectorOut()
   v = panel.value();
   QVERIFY( v.canConvert< QgsProcessingOutputLayerDefinition>() );
   QCOMPARE( v.value< QgsProcessingOutputLayerDefinition>().createOptions.value( QStringLiteral( "fileEncoding" ) ).toString(), QStringLiteral( "System" ) );
-  QCOMPARE( v.value< QgsProcessingOutputLayerDefinition>().sink.staticValue().toString(), TEST_DATA_DIR + QStringLiteral( "/test.shp" ) );
+  QCOMPARE( v.value< QgsProcessingOutputLayerDefinition>().sink.staticValue().toString(), QString( TEST_DATA_DIR + QStringLiteral( "/test.shp" ) ) );
 
   // optional, test skipping
   vector.setFlags( vector.flags() | QgsProcessingParameterDefinition::FlagOptional );
@@ -8154,7 +8154,7 @@ void TestProcessingGui::testOutputDefinitionWidgetRasterOut()
   v = panel.value();
   QVERIFY( v.canConvert< QgsProcessingOutputLayerDefinition>() );
   QCOMPARE( v.value< QgsProcessingOutputLayerDefinition>().createOptions.value( QStringLiteral( "fileEncoding" ) ).toString(), QStringLiteral( "System" ) );
-  QCOMPARE( v.value< QgsProcessingOutputLayerDefinition>().sink.staticValue().toString(), TEST_DATA_DIR + QStringLiteral( "/test.tif" ) );
+  QCOMPARE( v.value< QgsProcessingOutputLayerDefinition>().sink.staticValue().toString(), QString( TEST_DATA_DIR + QStringLiteral( "/test.tif" ) ) );
 
   // optional, test skipping
   raster.setFlags( raster.flags() | QgsProcessingParameterDefinition::FlagOptional );
@@ -8260,7 +8260,7 @@ void TestProcessingGui::testOutputDefinitionWidgetFolder()
   settings.setValue( QStringLiteral( "/Processing/Configuration/OUTPUTS_FOLDER" ), TEST_DATA_DIR );
   panel.setValue( QStringLiteral( "mystuff" ) );
   v = panel.value();
-  QCOMPARE( v.toString(), TEST_DATA_DIR + QStringLiteral( "/mystuff" ) );
+  QCOMPARE( v.toString(), QString( TEST_DATA_DIR + QStringLiteral( "/mystuff" ) ) );
 
   // optional, test skipping
   folder.setFlags( folder.flags() | QgsProcessingParameterDefinition::FlagOptional );
@@ -8361,7 +8361,7 @@ void TestProcessingGui::testOutputDefinitionWidgetFileOut()
   settings.setValue( QStringLiteral( "/Processing/Configuration/OUTPUTS_FOLDER" ), TEST_DATA_DIR );
   panel.setValue( QStringLiteral( "test.tif" ) );
   v = panel.value();
-  QCOMPARE( v.toString(), TEST_DATA_DIR + QStringLiteral( "/test.tif" ) );
+  QCOMPARE( v.toString(), QString( TEST_DATA_DIR + QStringLiteral( "/test.tif" ) ) );
 
   // optional, test skipping
   file.setFlags( file.flags() | QgsProcessingParameterDefinition::FlagOptional );
diff --git a/tests/src/gui/testqgsfilewidget.cpp b/tests/src/gui/testqgsfilewidget.cpp
index d2d5debd308..6717d761966 100644
--- a/tests/src/gui/testqgsfilewidget.cpp
+++ b/tests/src/gui/testqgsfilewidget.cpp
@@ -104,7 +104,7 @@ void TestQgsFileWidget::testDroppedFiles()
   mime->setUrls( QList<QUrl>() << QUrl::fromLocalFile( TEST_DATA_DIR + QStringLiteral( "/bug5598.shp" ) ) );
   event.reset( new QDropEvent( QPointF( 1, 1 ), Qt::CopyAction, mime.get(), Qt::LeftButton,  Qt::NoModifier ) );
   qobject_cast< QgsFileDropEdit * >( w->lineEdit() )->dropEvent( event.get() );
-  QCOMPARE( w->lineEdit()->text(), TEST_DATA_DIR + QStringLiteral( "/bug5598.shp" ) );
+  QCOMPARE( w->lineEdit()->text(), QString( TEST_DATA_DIR + QStringLiteral( "/bug5598.shp" ) ) );
 
   // also should support files dragged from browser
   mime->setUrls( QList<QUrl>() );
@@ -115,7 +115,7 @@ void TestQgsFileWidget::testDroppedFiles()
   mime.reset( QgsMimeDataUtils::encodeUriList( uriList ) );
   event.reset( new QDropEvent( QPointF( 1, 1 ), Qt::CopyAction, mime.get(), Qt::LeftButton,  Qt::NoModifier ) );
   qobject_cast< QgsFileDropEdit * >( w->lineEdit() )->dropEvent( event.get() );
-  QCOMPARE( w->lineEdit()->text(), TEST_DATA_DIR + QStringLiteral( "/mesh/quad_and_triangle.2dm" ) );
+  QCOMPARE( w->lineEdit()->text(), QString( TEST_DATA_DIR + QStringLiteral( "/mesh/quad_and_triangle.2dm" ) ) );
 
   QgsBrowserModel m;
   m.initialize();
@@ -124,14 +124,14 @@ void TestQgsFileWidget::testDroppedFiles()
   mime.reset( m.mimeData( QModelIndexList() << m.findItem( layerItem ) ) );
   event.reset( new QDropEvent( QPointF( 1, 1 ), Qt::CopyAction, mime.get(), Qt::LeftButton, Qt::NoModifier ) );
   qobject_cast< QgsFileDropEdit * >( w->lineEdit() )->dropEvent( event.get() );
-  QCOMPARE( w->lineEdit()->text(), QString( TEST_DATA_DIR ) + QStringLiteral( "/mesh/quad_and_triangle.txt" ) );
+  QCOMPARE( w->lineEdit()->text(), QString( QString( TEST_DATA_DIR ) + QStringLiteral( "/mesh/quad_and_triangle.txt" ) ) );
 
   // plain text should also be permitted
   mime = qgis::make_unique< QMimeData >();
   mime->setText( TEST_DATA_DIR + QStringLiteral( "/mesh/quad_and_triangle.2dm" ) );
   event.reset( new QDropEvent( QPointF( 1, 1 ), Qt::CopyAction, mime.get(), Qt::LeftButton,  Qt::NoModifier ) );
   qobject_cast< QgsFileDropEdit * >( w->lineEdit() )->dropEvent( event.get() );
-  QCOMPARE( w->lineEdit()->text(), TEST_DATA_DIR + QStringLiteral( "/mesh/quad_and_triangle.2dm" ) );
+  QCOMPARE( w->lineEdit()->text(), QString( TEST_DATA_DIR + QStringLiteral( "/mesh/quad_and_triangle.2dm" ) ) );
 
   mime.reset( new QMimeData() );
   mime->setUrls( QList<QUrl>() << QUrl::fromLocalFile( TEST_DATA_DIR + QStringLiteral( "/bug5598.shp" ) ) );
@@ -140,7 +140,7 @@ void TestQgsFileWidget::testDroppedFiles()
   w->setFilter( QStringLiteral( "Data (*.shp)" ) );
   w->setFilePath( QString() );
   qobject_cast< QgsFileDropEdit * >( w->lineEdit() )->dropEvent( event.get() );
-  QCOMPARE( w->lineEdit()->text(), TEST_DATA_DIR + QStringLiteral( "/bug5598.shp" ) );
+  QCOMPARE( w->lineEdit()->text(), QString( TEST_DATA_DIR + QStringLiteral( "/bug5598.shp" ) ) );
   w->setFilePath( QString() );
   // should be rejected, not compatible with filter
   mime->setUrls( QList<QUrl>() << QUrl::fromLocalFile( TEST_DATA_DIR + QStringLiteral( "/encoded_html.html" ) ) );
@@ -150,14 +150,14 @@ void TestQgsFileWidget::testDroppedFiles()
   // new filter, should be allowed now
   w->setFilter( QStringLiteral( "Data (*.shp);;HTML (*.HTML)" ) );
   qobject_cast< QgsFileDropEdit * >( w->lineEdit() )->dropEvent( event.get() );
-  QCOMPARE( w->lineEdit()->text(), TEST_DATA_DIR + QStringLiteral( "/encoded_html.html" ) );
+  QCOMPARE( w->lineEdit()->text(), QString( TEST_DATA_DIR + QStringLiteral( "/encoded_html.html" ) ) );
 
   //try with wildcard filter
   w->setFilter( QStringLiteral( "All files (*.*);;Data (*.shp);;HTML (*.HTML)" ) );
   mime->setUrls( QList<QUrl>() << QUrl::fromLocalFile( TEST_DATA_DIR + QStringLiteral( "/bug5598.prj" ) ) );
   event.reset( new QDropEvent( QPointF( 1, 1 ), Qt::CopyAction, mime.get(), Qt::LeftButton,  Qt::NoModifier ) );
   qobject_cast< QgsFileDropEdit * >( w->lineEdit() )->dropEvent( event.get() );
-  QCOMPARE( w->lineEdit()->text(), TEST_DATA_DIR + QStringLiteral( "/bug5598.prj" ) );
+  QCOMPARE( w->lineEdit()->text(), QString( TEST_DATA_DIR + QStringLiteral( "/bug5598.prj" ) ) );
 
   // try with folders
   w->setStorageMode( QgsFileWidget::GetDirectory );
@@ -166,7 +166,7 @@ void TestQgsFileWidget::testDroppedFiles()
   mime->setUrls( QList<QUrl>() << QUrl::fromLocalFile( TEST_DATA_DIR + QStringLiteral( "/mesh/quad_and_triangle.2dm" ) ) );
   event.reset( new QDropEvent( QPointF( 1, 1 ), Qt::CopyAction, mime.get(), Qt::LeftButton,  Qt::NoModifier ) );
   qobject_cast< QgsFileDropEdit * >( w->lineEdit() )->dropEvent( event.get() );
-  QCOMPARE( w->lineEdit()->text(), QString( TEST_DATA_DIR ) +  QStringLiteral( "/mesh" ) );
+  QCOMPARE( w->lineEdit()->text(), QString( QString( TEST_DATA_DIR ) +  QStringLiteral( "/mesh" ) ) );
 
   // but dropping a folder should work
   mime->setUrls( QList<QUrl>() << QUrl::fromLocalFile( TEST_DATA_DIR ) );
@@ -180,7 +180,7 @@ void TestQgsFileWidget::testDroppedFiles()
   mime.reset( m.mimeData( QModelIndexList() << m.findItem( dirItem ) ) );
   event.reset( new QDropEvent( QPointF( 1, 1 ), Qt::CopyAction, mime.get(), Qt::LeftButton, Qt::NoModifier ) );
   qobject_cast< QgsFileDropEdit * >( w->lineEdit() )->dropEvent( event.get() );
-  QCOMPARE( w->lineEdit()->text(), QString( TEST_DATA_DIR ) + QStringLiteral( "/mesh" ) );
+  QCOMPARE( w->lineEdit()->text(), QString( QString( TEST_DATA_DIR ) + QStringLiteral( "/mesh" ) ) );
 }
 
 void TestQgsFileWidget::testMultipleFiles()
diff --git a/tests/src/gui/testqgsnewdatabasetablewidget.cpp b/tests/src/gui/testqgsnewdatabasetablewidget.cpp
index 72666c18743..82c7d892aa9 100644
--- a/tests/src/gui/testqgsnewdatabasetablewidget.cpp
+++ b/tests/src/gui/testqgsnewdatabasetablewidget.cpp
@@ -273,7 +273,7 @@ void TestQgsNewDatabaseTableNameWidget::testWidgetSignalsGeopackage()
   QCOMPARE( w->table(), QString( "newTableName" ) );
   QCOMPARE( w->schema(), mGpkgPath );
   QCOMPARE( w->dataProviderKey(), QString( "ogr" ) );
-  QCOMPARE( w->uri(), mGpkgPath + QStringLiteral( "|layername=newTableName" ) );
+  QCOMPARE( w->uri(), QString( mGpkgPath + QStringLiteral( "|layername=newTableName" ) ) );
 #endif
 }