Test QDateTime behavior in DST gap

Historic QDateTime behavior when being asked to create a
QDateTime in the DST gap was to interpret the given date
as if it was in the time before that gap, mapping it to a point
in time after the gap. This has changed (after Qt 5.15) with
a04411119ead3d4473e4f0ac4bceedc585977b2f .
Since then, the given date is interpreted as if it was in the
time after the gap, thus being mapped to a point in time
before the gap.
This was not caught (in dev) by Coin because machines ran in
timezone "Atlantic/Reykjavik" which does not have DST since 1967.
This patch changes tests to always run in "Europe/Oslo".
A support function and each test-case thus need to use zone-time
instead of local time.

Fixes: QTBUG-86960
Fixes: QTBUG-89208
Change-Id: Iecce5898bf9711a10e7dfc0a25e4bbeaed1c8ade
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
(cherry picked from commit 3d785249ba43cf4bd895ed679bac2791e0130dc5)
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

2 files changed, 16 insertions, 11 deletions

diff --git a/tests/auto/corelib/time/qdatetime/tst_qdatetime.cpp b/tests/auto/corelib/time/qdatetime/tst_qdatetime.cpp
index 4a0fc81a9c..3f0af84e4e 100644
--- a/tests/auto/corelib/time/qdatetime/tst_qdatetime.cpp
+++ b/tests/auto/corelib/time/qdatetime/tst_qdatetime.cpp
@@ -2705,6 +2705,9 @@ void tst_QDateTime::fromStringStringFormat()
 #endif
         // OffsetFromUTC needs an offset check - we may as well do it for all:
         QCOMPARE(dt.offsetFromUtc(), expected.offsetFromUtc());
+    } else {
+        QCOMPARE(dt.isValid(), expected.isValid());
+        QCOMPARE(dt.toMSecsSinceEpoch(), expected.toMSecsSinceEpoch());
     }
 }
 
@@ -3176,7 +3179,9 @@ void tst_QDateTime::daylightTransitions() const
         QDateTime missing(QDate(2012, 3, 25), QTime(2, 0, 0));
         QVERIFY(!missing.isValid());
         QCOMPARE(missing.date(), QDate(2012, 3, 25));
-        QCOMPARE(missing.time(), QTime(2, 0, 0));
+        QCOMPARE(missing.time(), QTime(2, 0));
+        // datetimeparser relies on toMSecsSinceEpoch to still work:
+        QCOMPARE(missing.toMSecsSinceEpoch(), daylight2012);
 
         QDateTime after(QDate(2012, 3, 25), QTime(3, 0, 0));
         QVERIFY(after.isValid());
diff --git a/tests/auto/widgets/widgets/qdatetimeedit/tst_qdatetimeedit.cpp b/tests/auto/widgets/widgets/qdatetimeedit/tst_qdatetimeedit.cpp
index 1582835fda..456d0d55e0 100644
--- a/tests/auto/widgets/widgets/qdatetimeedit/tst_qdatetimeedit.cpp
+++ b/tests/auto/widgets/widgets/qdatetimeedit/tst_qdatetimeedit.cpp
@@ -4475,7 +4475,7 @@ static QDateTime findSpring(int year, const QTimeZone &timeZone)
         return QDateTime();
 
     // Southern hemisphere spring is after midsummer
-    const QDateTime midSummer = QDate(year, 6, 21).startOfDay();
+    const QDateTime midSummer = QDate(year, 6, 21).startOfDay(timeZone);
     const QTimeZone::OffsetData transition =
         midSummer.isDaylightTime() ? timeZone.previousTransition(midSummer)
                                    : timeZone.nextTransition(midSummer);
@@ -4596,7 +4596,7 @@ void tst_QDateTimeEdit::stepIntoDSTGap_data()
     QTest::addColumn<int>("steps");
     QTest::addColumn<QDateTime>("end");
 
-    const QTimeZone timeZone = QTimeZone::systemTimeZone();
+    const QTimeZone timeZone = QTimeZone("Europe/Oslo");
     if (!timeZone.hasDaylightTime())
         QSKIP("This test needs to run in a timezone that observes DST!");
 
@@ -4611,14 +4611,14 @@ void tst_QDateTimeEdit::stepIntoDSTGap_data()
     // change hour
     if (springGap.hour() != 0) {
         QTest::addRow("hour up into %s gap", qPrintable(springGap.toString("hh:mm")))
-            << QDateTime(spring, springGap.addSecs(-3600))
+            << QDateTime(spring, springGap.addSecs(-3600), timeZone)
             << QDateTimeEdit::HourSection
             << +1
             << springTransition;
 
         // 3:00:10 into 2:00:10 should get us to 1:00:10
         QTest::addRow("hour down into %s gap", qPrintable(springGap.toString("hh:mm")))
-            << QDateTime(spring, springGap.addSecs(3610))
+            << QDateTime(spring, springGap.addSecs(3610), timeZone)
             << QDateTimeEdit::HourSection
             << -1
             << QDateTime(spring, springGap.addSecs(-3590));
@@ -4628,7 +4628,7 @@ void tst_QDateTimeEdit::stepIntoDSTGap_data()
     if (spring.day() != 1) {
         // today's 2:05 is tomorrow's 3:05
         QTest::addRow("day up into %s gap", qPrintable(springGap.toString("hh:mm")))
-            << QDateTime(spring.addDays(-1), springGap.addSecs(300))
+            << QDateTime(spring.addDays(-1), springGap.addSecs(300), timeZone)
             << QDateTimeEdit::DaySection
             << +1
             << springTransition.addSecs(300);
@@ -4636,7 +4636,7 @@ void tst_QDateTimeEdit::stepIntoDSTGap_data()
 
     if (spring.day() != spring.daysInMonth()) {
         QTest::addRow("day down into %s gap", qPrintable(springGap.toString("hh:mm")))
-            << QDateTime(spring.addDays(1), springGap)
+            << QDateTime(spring.addDays(1), springGap, timeZone)
             << QDateTimeEdit::DaySection
             << -1
             << springTransition;
@@ -4644,24 +4644,24 @@ void tst_QDateTimeEdit::stepIntoDSTGap_data()
 
     // 2018-03-25 - change month
     QTest::addRow("month up into %s gap", qPrintable(springGap.toString("hh:mm")))
-        << QDateTime(spring.addMonths(-1), springGap)
+        << QDateTime(spring.addMonths(-1), springGap, timeZone)
         << QDateTimeEdit::MonthSection
         << +1
         << springTransition;
     QTest::addRow("month down into %s gap", qPrintable(springGap.toString("hh:mm")))
-        << QDateTime(spring.addMonths(1), springGap)
+        << QDateTime(spring.addMonths(1), springGap, timeZone)
         << QDateTimeEdit::MonthSection
         << -1
         << springTransition;
 
     // 2018-03-25 - change year
     QTest::addRow("year up into %s gap", qPrintable(springGap.toString("hh:mm")))
-        << QDateTime(spring.addYears(-1), springGap)
+        << QDateTime(spring.addYears(-1), springGap, timeZone)
         << QDateTimeEdit::YearSection
         << +1
         << springTransition;
     QTest::addRow("year down into %s gap", qPrintable(springGap.toString("hh:mm")))
-        << QDateTime(spring.addYears(1), springGap)
+        << QDateTime(spring.addYears(1), springGap, timeZone)
         << QDateTimeEdit::YearSection
         << -1
         << springTransition;