Add some more QDate::{start,end}OfDay() tests

While investigating an assertion failure I noticed that the existing
tests didn't even exercise these methods for local time or zone time.
Of course, we can't robustly test these time-specs, due to vagueries
of offset details and zone availability, but we can at least verify
that they return date-times on the specified date. Add a test-case for
the start of 1900, on which the assertions were first seen; it is the
earliest moment representable with tm_year >= 0, after all.

One of these tests fails on 6.2 but the fix for that (as opposed to
the the assertion) requires 6.3's improvements to the handling of
time_t's fuller range - too risky a change to pick back to 6.2.

Task-number: QTBUG-99747
Change-Id: I98f5d7850a701972b2d8ea2ce203a2b3e7071354
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
(cherry picked from commit 830fd1908ba14d434d1715304a430b62d0281eee)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 12 insertions, 0 deletions

diff --git a/tests/auto/corelib/time/qdate/tst_qdate.cpp b/tests/auto/corelib/time/qdate/tst_qdate.cpp
index 911ad90a7a..4a5725c42e 100644
--- a/tests/auto/corelib/time/qdate/tst_qdate.cpp
+++ b/tests/auto/corelib/time/qdate/tst_qdate.cpp
@@ -568,6 +568,7 @@ void tst_QDate::startOfDay_endOfDay_fixed_data()
     } data[] = {
         { "epoch", QDate(1970, 1, 1) },
         { "y2k-leap-day", QDate(2000, 2, 29) },
+        { "start-1900", QDate(1900, 1, 1) }, // QTBUG-99747
         // Just outside the start and end of 32-bit time_t:
         { "pre-sign32", QDate(start32sign.date().year(), 1, 1) },
         { "post-sign32", QDate(end32sign.date().year(), 12, 31) },
@@ -605,6 +606,17 @@ void tst_QDate::startOfDay_endOfDay_fixed()
         QCOMPARE(date.addDays(1).startOfDay(Qt::OffsetFromUTC, offset).addMSecs(-1), end);
         QCOMPARE(date.addDays(-1).endOfDay(Qt::OffsetFromUTC, offset).addMSecs(1), start);
     }
+
+    // Minimal testing for LocalTime and TimeZone
+    QCOMPARE(date.startOfDay(Qt::LocalTime).date(), date);
+    QCOMPARE(date.endOfDay(Qt::LocalTime).date(), date);
+#if QT_CONFIG(timezone)
+    const QTimeZone cet("Europe/Oslo");
+    if (cet.isValid()) {
+        QCOMPARE(date.startOfDay(cet).date(), date);
+        QCOMPARE(date.endOfDay(cet).date(), date);
+    }
+#endif
 }
 
 void tst_QDate::startOfDay_endOfDay_bounds()