Prevent static functions of Q[Gui]Application from crashing if there is no instance.

Add tests.

Task-number: QTBUG-44499
Change-Id: I160b089ad3f23ab71a87519e50f8a2ef5d2a4a6f
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>

2 files changed, 62 insertions, 0 deletions

diff --git a/tests/auto/gui/kernel/qguiapplication/tst_qguiapplication.cpp b/tests/auto/gui/kernel/qguiapplication/tst_qguiapplication.cpp
index 3cf7803cfb..b921e1519f 100644
--- a/tests/auto/gui/kernel/qguiapplication/tst_qguiapplication.cpp
+++ b/tests/auto/gui/kernel/qguiapplication/tst_qguiapplication.cpp
@@ -77,6 +77,8 @@ private slots:
     void layoutDirection();
     void globalShareContext();
 
+    void staticFunctions();
+
     void settableStyleHints_data();
     void settableStyleHints(); // Needs to run last as it changes style hints.
 };
@@ -966,6 +968,42 @@ void tst_QGuiApplication::globalShareContext()
 #endif
 }
 
+// Test that static functions do not crash if there is no application instance.
+void tst_QGuiApplication::staticFunctions()
+{
+    QGuiApplication::setApplicationDisplayName(QString());
+    QGuiApplication::applicationDisplayName();
+    QGuiApplication::allWindows();
+    QGuiApplication::topLevelWindows();
+    QGuiApplication::topLevelAt(QPoint(0, 0));
+    QGuiApplication::setWindowIcon(QIcon());
+    QGuiApplication::windowIcon();
+    QGuiApplication::platformName();
+    QGuiApplication::modalWindow();
+    QGuiApplication::focusWindow();
+    QGuiApplication::focusObject();
+    QGuiApplication::primaryScreen();
+    QGuiApplication::screens();
+    QGuiApplication::overrideCursor();
+    QGuiApplication::setOverrideCursor(QCursor());
+    QGuiApplication::changeOverrideCursor(QCursor());
+    QGuiApplication::restoreOverrideCursor();
+    QGuiApplication::keyboardModifiers();
+    QGuiApplication::queryKeyboardModifiers();
+    QGuiApplication::mouseButtons();
+    QGuiApplication::setLayoutDirection(Qt::LeftToRight);
+    QGuiApplication::layoutDirection();
+    QGuiApplication::styleHints();
+    QGuiApplication::setDesktopSettingsAware(true);
+    QGuiApplication::desktopSettingsAware();
+    QGuiApplication::inputMethod();
+    QGuiApplication::platformNativeInterface();
+    QGuiApplication::platformFunction(QByteArrayLiteral("bla"));
+    QGuiApplication::setQuitOnLastWindowClosed(true);
+    QGuiApplication::quitOnLastWindowClosed();
+    QGuiApplication::applicationState();
+}
+
 void tst_QGuiApplication::settableStyleHints_data()
 {
     QTest::addColumn<bool>("appInstance");
diff --git a/tests/auto/widgets/kernel/qapplication/tst_qapplication.cpp b/tests/auto/widgets/kernel/qapplication/tst_qapplication.cpp
index bab3337c0c..c3e8b51ccd 100644
--- a/tests/auto/widgets/kernel/qapplication/tst_qapplication.cpp
+++ b/tests/auto/widgets/kernel/qapplication/tst_qapplication.cpp
@@ -172,6 +172,8 @@ private slots:
 
     void abortQuitOnShow();
 
+    void staticFunctions();
+
     void settableStyleHints_data();
     void settableStyleHints();  // Needs to run last as it changes style hints.
 };
@@ -2299,6 +2301,28 @@ void tst_QApplication::abortQuitOnShow()
     QCOMPARE(app.exec(), 1);
 }
 
+// Test that static functions do not crash if there is no application instance.
+void tst_QApplication::staticFunctions()
+{
+    QApplication::setStyle(QStringLiteral("blub"));
+    QApplication::colorSpec();
+    QApplication::setColorSpec(42);
+    QApplication::allWidgets();
+    QApplication::topLevelWidgets();
+    QApplication::desktop();
+    QApplication::activePopupWidget();
+    QApplication::activeModalWidget();
+    QApplication::focusWidget();
+    QApplication::activeWindow();
+    QApplication::setActiveWindow(Q_NULLPTR);
+    QApplication::widgetAt(QPoint(0, 0));
+    QApplication::topLevelAt(QPoint(0, 0));
+    QApplication::setGlobalStrut(QSize(0, 0));
+    QApplication::globalStrut();
+    QApplication::isEffectEnabled(Qt::UI_General);
+    QApplication::setEffectEnabled(Qt::UI_General, false);
+}
+
 void tst_QApplication::settableStyleHints_data()
 {
     QTest::addColumn<bool>("appInstance");