Convert date-time faithfully in QDateTimeEdit::setDateTime()

Previously, setDateTime() was documented to ignore the new date-time's
time-spec. It used the date and time (determined using that timespec)
with the QDateTimeEdit's configured spec. It is debatable whether that
really counts as ignoring its time-spec. All the same, that's what it
did. Fixing it is a behavior change. Added tests.

[ChangeLog][QtWidgets][QDateTimeEdit] QDateTimeEdit::setDateTime() now
converts the new datetime to the QDateTimeEdit's time-spec, rather
than combining its date and time (determined using the time spec it
came with) with the QDateTimeEdit's date and time.

Fixes: QTBUG-71181
Change-Id: Ibf0bd87723c3957ca00a2199d51d992032ef57ee
Reviewed-by: Paul Wicking <paul.wicking@qt.io>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Konstantin Shegunov <kshegunov@gmail.com>

1 files changed, 50 insertions, 0 deletions

diff --git a/tests/auto/widgets/widgets/qdatetimeedit/tst_qdatetimeedit.cpp b/tests/auto/widgets/widgets/qdatetimeedit/tst_qdatetimeedit.cpp
index 264625777f..9eae1f10ea 100644
--- a/tests/auto/widgets/widgets/qdatetimeedit/tst_qdatetimeedit.cpp
+++ b/tests/auto/widgets/widgets/qdatetimeedit/tst_qdatetimeedit.cpp
@@ -262,6 +262,8 @@ private slots:
     void timeSpec();
     void timeSpecBug();
     void timeSpecInit();
+    void setDateTime_data();
+    void setDateTime();
 
     void monthEdgeCase();
     void setLocale();
@@ -3476,6 +3478,54 @@ void tst_QDateTimeEdit::timeSpecInit()
     QCOMPARE(widget.dateTime(), utc);
 }
 
+void tst_QDateTimeEdit::setDateTime_data()
+{
+    QTest::addColumn<Qt::TimeSpec>("spec");
+    QDateTime localNoon(QDate(2019, 12, 24), QTime(12, 0), Qt::LocalTime);
+#if 0 // Not yet supported
+    QTest::addColumn<int>("offset");
+    QTest::addColumn<QByteArray>("zoneName");
+
+    QTest::newRow("OffsetFromUTC/LocalTime")
+        << Qt::OffsetFromUTC << 7200 << ""
+        << localNoon << localNoon.toOffsetFromUtc(7200);
+#if QT_CONFIG(timezone)
+    QTest::newRow("TimeZone/LocalTime")
+        << Qt::TimeZone << 0 << "Europe/Berlin"
+        << localNoon << localNoon.toTimeZone(QTimeZone("Europe/Berlin"));
+#endif
+#endif // unsupported
+    QTest::addColumn<QDateTime>("store");
+    QTest::addColumn<QDateTime>("expect");
+    QTest::newRow("LocalTime/LocalTime")
+        << Qt::LocalTime // << 0 << ""
+        << localNoon << localNoon;
+    QTest::newRow("LocalTime/UTC")
+        << Qt::LocalTime // << 0 << ""
+        << localNoon.toUTC() << localNoon;
+    QTest::newRow("UTC/LocalTime")
+        << Qt::UTC // << 0 << ""
+        << localNoon << localNoon.toUTC();
+    QTest::newRow("UTC/UTC")
+        << Qt::UTC // << 0 << ""
+        << localNoon.toUTC() << localNoon.toUTC();
+}
+
+void tst_QDateTimeEdit::setDateTime()
+{
+    QFETCH(const Qt::TimeSpec, spec);
+#if 0 // Not yet supported
+    QFETCH(const int, offset);
+    QFETCH(const QByteArray, zoneName);
+#endif // configuring the spec, when OffsetFromUTC or TimeZone
+    QFETCH(const QDateTime, store);
+    QFETCH(const QDateTime, expect);
+    QDateTimeEdit editor;
+    editor.setTimeSpec(spec);
+    editor.setDateTime(store);
+    QCOMPARE(editor.dateTime(), expect);
+}
+
 void tst_QDateTimeEdit::cachedDayTest()
 {
     testWidget->setDisplayFormat("MM/dd");