Add test for QgsScaleRangeWidget::setScaleRange

See #15463 as this test guards after the fix for that bug
(minScale visibility corrupted upon project load)

tests/src/gui/CMakeLists.txt

@@ -122,6 +122,7 @@ ADD_QGIS_TEST(projectionissues testprojectionissues.cpp)
 ADD_QGIS_TEST(qgsguitest testqgsgui.cpp)
 ADD_QGIS_TEST(rubberbandtest testqgsrubberband.cpp)
 ADD_QGIS_TEST(scalecombobox testqgsscalecombobox.cpp)
+ADD_QGIS_TEST(scalerangewidget testqgsscalerangewidget.cpp)
 ADD_QGIS_TEST(spinbox testqgsspinbox.cpp)
 ADD_QGIS_TEST(sqlcomposerdialog testqgssqlcomposerdialog.cpp)
 ADD_QGIS_TEST(editorwidgetregistrytest testqgseditorwidgetregistry.cpp)

tests/src/gui/testqgsscalerangewidget.cpp

@@ -0,0 +1,93 @@
+/***************************************************************************
+                         testqgsscalerangewidget.cpp
+                         ---------------------------
+    begin                : May 2017
+    copyright            : (C) 2017 by Sandro Santilli
+    email                : strk at kbt dot io
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   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 "qgsscalerangewidget.h"
+#include "qgsapplication.h"
+#include "qgslogger.h"
+
+#include <QObject>
+#include <QLineEdit>
+#include <QComboBox>
+#include <QtTest/QSignalSpy>
+
+#include <memory>
+
+/** @ingroup UnitTests
+ * This is a unit test for the scale range widget
+ *
+ * @see QgsScaleRangeWidget
+ */
+class TestQgsScaleRangeWidget : public QObject
+{
+    Q_OBJECT
+  private slots:
+    void initTestCase();// will be called before the first testfunction is executed.
+    void cleanupTestCase();// will be called after the last testfunction was executed.
+    void init();// will be called before each testfunction is executed.
+    void cleanup();// will be called after every testfunction.
+    void test_setScaleRange();
+  private:
+    std::unique_ptr<QgsScaleRangeWidget> widget;
+};
+
+void TestQgsScaleRangeWidget::initTestCase()
+{
+  QgsApplication::init();
+  QgsApplication::initQgis();
+}
+
+void TestQgsScaleRangeWidget::cleanupTestCase()
+{
+  QgsApplication::exitQgis();
+}
+
+void TestQgsScaleRangeWidget::init()
+{
+  widget.reset( new QgsScaleRangeWidget() );
+}
+
+void TestQgsScaleRangeWidget::cleanup()
+{
+}
+
+void TestQgsScaleRangeWidget::test_setScaleRange()
+{
+  // Test that setting scale range is always honoured
+  // rather than being limited by previously set
+  // max or min.
+  // See https://issues.qgis.org/issues/15463
+
+  widget->setScaleRange( 4.0, 6.0 );
+  QCOMPARE( widget->minimumScale(), 4.0 );
+  QCOMPARE( widget->maximumScale(), 6.0 );
+
+  widget->setScaleRange( 8.0, 10.0 );
+  QCOMPARE( widget->minimumScale(), 8.0 );
+  QCOMPARE( widget->maximumScale(), 10.0 );
+
+  widget->setScaleRange( 2.0, 4.0 );
+  QCOMPARE( widget->minimumScale(), 2.0 );
+  QCOMPARE( widget->maximumScale(), 4.0 );
+
+  // TODO: test passing min > max
+
+}
+
+QGSTEST_MAIN( TestQgsScaleRangeWidget )
+#include "testqgsscalerangewidget.moc"