Extend QTest::failOnWarning() to a no-parameter fail-on-any-warning

Many users (albeit mostly in qtdeclarative) of failOnWarning() are
passing a catch-all regexp, which is only supported when regular
expression support is enabled. Make their lives easier and those
checks independent of the feature by adding a third overload, taking
no parameter, that fails on any (unanticipated) warning.

Implementation is trivial - just put a null QVariant in
failOnWarningList; it won't match either check on the entry that might
exempt a test from failing on a warning, so any warning at all will
trigger failure.

[ChangeLog][QtTest] QTest::failOnWarning() now has a no-parameter
overload to support the common case of fail-on-any-warning, without
needing to construct a match-everything regular expression.

Change-Id: Ic693f1c8619fd6e495543b85737d566134cf9d20
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

src/testlib/qtestcase.cpp

@@ -2201,6 +2201,19 @@ void QTest::ignoreMessage(QtMsgType type, const QRegularExpression &messagePatte
 }
 #endif // QT_CONFIG(regularexpression)
 
+/*!
+    \since 6.8
+    \overload failOnWarning()
+
+    Appends a test failure to the test log if any warning is output.
+
+    \sa failOnWarning()
+*/
+void QTest::failOnWarning()
+{
+    return QTestLog::failOnWarning();
+}
+
 /*!
     \since 6.3
     \overload failOnWarning()
@@ -2247,7 +2260,17 @@ void QTest::failOnWarning(const char *message)
     \code
     void FileTest::init()
     {
-        QTest::failOnWarning(QRegularExpression(".?"));
+        QTest::failOnWarning(
+            QRegularExpression("QFile::.*: File(.*) already open"));
+    }
+    \endcode
+
+    For the common case of failing on \e any warning pass no parameter:
+
+    \code
+    void FileTest::init()
+    {
+        QTest::failOnWarning();
     }
     \endcode
 

src/testlib/qtestcase.h

@@ -435,6 +435,7 @@ namespace QTest
 #if QT_CONFIG(regularexpression)
     Q_TESTLIB_EXPORT void ignoreMessage(QtMsgType type, const QRegularExpression &messagePattern);
 #endif
+    Q_TESTLIB_EXPORT void failOnWarning();
     Q_TESTLIB_EXPORT void failOnWarning(const char *message);
 #if QT_CONFIG(regularexpression)
     Q_TESTLIB_EXPORT void failOnWarning(const QRegularExpression &messagePattern);

src/testlib/qtestlog.cpp

@@ -629,6 +629,11 @@ void QTestLog::ignoreMessage(QtMsgType type, const QRegularExpression &expressio
 }
 #endif // QT_CONFIG(regularexpression)
 
+void QTestLog::failOnWarning()
+{
+    QTest::failOnWarningList.push_back({});
+}
+
 void QTestLog::failOnWarning(const char *msg)
 {
     QTest::failOnWarningList.push_back(QString::fromUtf8(msg));

src/testlib/qtestlog_p.h

@@ -71,6 +71,7 @@ public:
 #ifndef QT_NO_REGULAREXPRESSION
     static void ignoreMessage(QtMsgType type, const QRegularExpression &expression);
 #endif
+    static void failOnWarning();
     static void failOnWarning(const char *msg);
 #ifndef QT_NO_REGULAREXPRESSION
     static void failOnWarning(const QRegularExpression &expression);

tests/auto/corelib/itemmodels/qitemselectionmodel/tst_qitemselectionmodel.cpp

@@ -2981,7 +2981,7 @@ void tst_QItemSelectionModel::destroyModel()
     selectionModel->setCurrentIndex(itemModel->index(1, 0), QItemSelectionModel::Select);
     QVERIFY(selectionModel->currentIndex().isValid());
 
-    QTest::failOnWarning(QRegularExpression(".*"));
+    QTest::failOnWarning();
     itemModel.reset();
     QVERIFY(!selectionModel->currentIndex().isValid());
     QVERIFY(selectionModel->selection().isEmpty());