[tests] Add tests for setting extent in 'Export Map to Image/PDF' dialogs, both with normal behavior and with locking the scale activated

src/app/qgsmapsavedialog.h

@@ -109,6 +109,8 @@ class APP_EXPORT QgsMapSaveDialog : public QDialog, private Ui::QgsMapSaveDialog
     float mDevicePixelRatio;
 
     QString mInfoDetails;
+
+    friend class TestQgsMapSaveDialog;
 };
 
 #endif // QGSMAPSAVEDIALOG_H

tests/src/app/CMakeLists.txt

@@ -23,6 +23,7 @@ set(TESTS
   testqgsidentify.cpp
   testqgslayerpropertiesdialogs.cpp
   testqgsmapcanvasdockwidget.cpp
+  testqgsmapsavedialog.cpp
   testqgsmaptooladdpart.cpp
   testqgsmaptooldeletepart.cpp
   testqgsmaptooladdring.cpp

tests/src/app/testqgsmapsavedialog.cpp

@@ -0,0 +1,94 @@
+/***************************************************************************
+     testqgsmapsavedialog.cpp
+     ------------------------------
+    Date                 : September 2025
+    Copyright            : (C) 2025 by Germán Carrillo
+    Email                : german at opengis dot ch
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgstest.h"
+#include <QObject>
+
+#include "qgisapp.h"
+#include "qgsapplication.h"
+#include "qgsmapsavedialog.h"
+#include "qgsmapcanvas.h"
+
+
+class TestQgsMapSaveDialog : public QgsTest
+{
+    Q_OBJECT
+
+  public:
+    TestQgsMapSaveDialog()
+      : QgsTest( QStringLiteral( "Map save dialogs" ) )
+    {}
+
+  private:
+    QgisApp *mQgisApp = nullptr;
+
+  private slots:
+
+    void initTestCase()
+    {
+      QgsApplication::init();
+      QgsApplication::initQgis();
+      mQgisApp = new QgisApp();
+    }
+
+    void cleanupTestCase()
+    {
+      QgsApplication::exitQgis();
+    }
+
+    void testUpdateExtent()
+    {
+      // Set up base canvas
+      QgsMapCanvas canvas;
+      canvas.setDestinationCrs( QgsCoordinateReferenceSystem( QStringLiteral( "EPSG:3857" ) ) );
+      canvas.setFrameStyle( QFrame::NoFrame );
+      canvas.resize( 800, 600 );
+      canvas.show(); // to make the canvas resize
+      canvas.hide();
+      canvas.setExtent( QgsRectangle( 623913, 5720967, 1215325, 6068610 ) );
+
+      // Set up dialog
+      QgsMapSaveDialog dialog( nullptr, &canvas );
+      dialog.updateDpi( 96 );
+      dialog.mLockScale->setChecked( false ); // Default, let's make it explicit
+
+      // Check initial status
+      QCOMPARE( dialog.mScaleWidget->scale(), 2794072 );
+      QCOMPARE( dialog.mDpi, 96 );
+
+      // Check update extent without locking the scale
+      dialog.mScaleWidget->setScale( 10000 ); // First set a different arbitrary scale
+      QCOMPARE( dialog.mScaleWidget->scale(), 10000 );
+
+      QgsRectangle canvasExtent( 1028930.8433, 5910111.234, 1031976.2192, 5912395.266 );
+      canvas.setExtent( canvasExtent );
+      dialog.mExtentGroupBox->setOutputExtentFromCurrent(); // Same as set extent from "Map Canvas Extent"
+      QCOMPARE( dialog.mExtentGroupBox->outputExtent(), canvasExtent );
+      QCOMPARE( dialog.mScaleWidget->scale(), 14388 );
+
+      // Check update extent locking the scale
+      dialog.mScaleWidget->setScale( 10000 ); // First set a different arbitrary scale
+      QCOMPARE( dialog.mScaleWidget->scale(), 10000 );
+      dialog.mLockScale->setChecked( true );
+
+      canvas.setExtent( canvasExtent );
+      dialog.mExtentGroupBox->setOutputExtentFromCurrent(); // Same as set extent from "Map Canvas Extent"
+      QCOMPARE( dialog.mExtentGroupBox->outputExtent(), canvasExtent );
+      QCOMPARE( dialog.mScaleWidget->scale(), 10000 ); // Our arbitrary scale is kept!
+    }
+};
+
+QGSTEST_MAIN( TestQgsMapSaveDialog )
+#include "testqgsmapsavedialog.moc"