Restore previous 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 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 patch restores the historic behavior.
This was not caught 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".
Driveby: Test function "findSpring" did some operations in
local time, even though being asked to work in a specific
time zone. Fixed that.

Fixes: QTBUG-86960
Fixes: QTBUG-89208
Pick-to: 6.0 5.15
Change-Id: Iecce5898bf9711a10e7dfc0a25e4bbeaed1c8ade
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/tests/auto/corelib/time/qdatetime/tst_qdatetime.cpp b/tests/auto/corelib/time/qdatetime/tst_qdatetime.cpp
index 44916e96f5..e28ae128c8 100644
--- a/tests/auto/corelib/time/qdatetime/tst_qdatetime.cpp
+++ b/tests/auto/corelib/time/qdatetime/tst_qdatetime.cpp
@@ -2826,6 +2826,9 @@ 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());
     }
 }
 
@@ -3250,6 +3253,8 @@ void tst_QDateTime::daylightTransitions() const
         QVERIFY(!missing.isValid());
         QCOMPARE(missing.date(), QDate(2012, 3, 25));
         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));
         QVERIFY(after.isValid());