Reverse iteration in QMetaEnum::valueToKeys().

Otherwise, values that are composed of others are not handled
correctly. For example,
Qt::Dialog|Qt::FramelessWindowHint (Qt::Dialog=0x2|Qt::Window)
is currently output as
"Window|FramelessWindowHint" since
Qt::Window matches first and its bits are removed from the flag value
so that Qt::Dialog in the next iteration no longer matches.

Change-Id: I67db5c977c75f887392aa8f345c5e6e9d82c5c26
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/tests/auto/corelib/kernel/qmetaenum/tst_qmetaenum.cpp b/tests/auto/corelib/kernel/qmetaenum/tst_qmetaenum.cpp
index e81e105bfb..17b00ebf63 100644
--- a/tests/auto/corelib/kernel/qmetaenum/tst_qmetaenum.cpp
+++ b/tests/auto/corelib/kernel/qmetaenum/tst_qmetaenum.cpp
@@ -46,6 +46,8 @@ public:
 
 private slots:
     void fromType();
+    void valuesToKeys_data();
+    void valuesToKeys();
 };
 
 void tst_QMetaEnum::fromType()
@@ -57,5 +59,37 @@ void tst_QMetaEnum::fromType()
     QCOMPARE(meta.keyCount(), 2);
 }
 
+Q_DECLARE_METATYPE(Qt::WindowFlags)
+
+void tst_QMetaEnum::valuesToKeys_data()
+{
+   QTest::addColumn<Qt::WindowFlags>("windowFlags");
+   QTest::addColumn<QByteArray>("expected");
+
+   QTest::newRow("Window")
+       << Qt::WindowFlags(Qt::Window)
+       << QByteArrayLiteral("Window");
+
+   // Verify that Qt::Dialog does not cause 'Window' to appear in the output.
+   QTest::newRow("Frameless_Dialog")
+       << (Qt::Dialog | Qt::FramelessWindowHint)
+       << QByteArrayLiteral("Dialog|FramelessWindowHint");
+
+   // Similarly, Qt::WindowMinMaxButtonsHint should not show up as
+   // WindowMinimizeButtonHint|WindowMaximizeButtonHint
+   QTest::newRow("Tool_MinMax_StaysOnTop")
+       << (Qt::Tool | Qt::WindowMinMaxButtonsHint | Qt::WindowStaysOnTopHint)
+       << QByteArrayLiteral("Tool|WindowMinMaxButtonsHint|WindowStaysOnTopHint");
+}
+
+void tst_QMetaEnum::valuesToKeys()
+{
+    QFETCH(Qt::WindowFlags, windowFlags);
+    QFETCH(QByteArray, expected);
+
+    QMetaEnum me = QMetaEnum::fromType<Qt::WindowFlags>();
+    QCOMPARE(me.valueToKeys(windowFlags), expected);
+}
+
 QTEST_MAIN(tst_QMetaEnum)
 #include "tst_qmetaenum.moc"