tst_QTimeZone: improve readability of code and failure reports

When QCOMPARE(,) reports two 12-digit numbers, it's not always
immediately obvious what the difference is (much less what 1/3600000
of it is); nor is it obvious that (or why) a given 12-digit number is
in fact correct.  In contrast, our eyes can make sense of a
QDateTime's reported value quite well, enabling us to see what's
different; and it's possible to at least confirm the plausibility of
2-or-3 am on a spring or autumn day at a plausible transition (or even
to confirm it exactly by consulting suitable web-sites).  Also
document the actual transition happening in each case (since I *did*
consult a suitable web-site).  So prefer to QCOMPARE(,) two QDateTime
values instead of two 12-digit qint64s.

Where a that would be unsuitable, at least compare the difference to
zero, to make the error easier to understand (except when one of the
twelve-digit numbers consists entirely of 9s; that, for once, actually
is easy to see).

Write various multiples of 3600 as the relevant intelligible whole
number times 3600, rather than premultiplying, to make it obvious to
reders what's going on.

None of this changes what is actually tested.

Change-Id: I488e751283a55d4623c93612af13ad631144900d
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 64 insertions, 36 deletions

diff --git a/tests/auto/corelib/tools/qtimezone/tst_qtimezone.cpp b/tests/auto/corelib/tools/qtimezone/tst_qtimezone.cpp
index ccad9299d3..767236603a 100644
--- a/tests/auto/corelib/tools/qtimezone/tst_qtimezone.cpp
+++ b/tests/auto/corelib/tools/qtimezone/tst_qtimezone.cpp
@@ -167,11 +167,11 @@ void tst_QTimeZone::createTest()
     QDateTime jun = QDateTime(QDate(2012, 6, 1), QTime(0, 0, 0), Qt::UTC);
     QDateTime janPrev = QDateTime(QDate(2011, 1, 1), QTime(0, 0, 0), Qt::UTC);
 
-    QCOMPARE(tz.offsetFromUtc(jan), 46800);
-    QCOMPARE(tz.offsetFromUtc(jun), 43200);
+    QCOMPARE(tz.offsetFromUtc(jan), 13 * 3600);
+    QCOMPARE(tz.offsetFromUtc(jun), 12 * 3600);
 
-    QCOMPARE(tz.standardTimeOffset(jan), 43200);
-    QCOMPARE(tz.standardTimeOffset(jun), 43200);
+    QCOMPARE(tz.standardTimeOffset(jan), 12 * 3600);
+    QCOMPARE(tz.standardTimeOffset(jun), 12 * 3600);
 
     QCOMPARE(tz.daylightTimeOffset(jan), 3600);
     QCOMPARE(tz.daylightTimeOffset(jun), 0);
@@ -183,38 +183,46 @@ void tst_QTimeZone::createTest()
     // Only test transitions if host system supports them
     if (tz.hasTransitions()) {
         QTimeZone::OffsetData tran = tz.nextTransition(jan);
-        QCOMPARE(tran.atUtc.toMSecsSinceEpoch(), (qint64)1333202400000);
-        QCOMPARE(tran.offsetFromUtc, 43200);
-        QCOMPARE(tran.standardTimeOffset, 43200);
+        // 2012-04-01 03:00 NZDT, +13 -> +12
+        QCOMPARE(tran.atUtc,
+                 QDateTime(QDate(2012, 4, 1), QTime(3, 0), Qt::OffsetFromUTC, 13 * 3600));
+        QCOMPARE(tran.offsetFromUtc, 12 * 3600);
+        QCOMPARE(tran.standardTimeOffset, 12 * 3600);
         QCOMPARE(tran.daylightTimeOffset, 0);
 
         tran = tz.nextTransition(jun);
-        QCOMPARE(tran.atUtc.toMSecsSinceEpoch(), (qint64)1348927200000);
-        QCOMPARE(tran.offsetFromUtc, 46800);
-        QCOMPARE(tran.standardTimeOffset, 43200);
+        // 2012-09-30 02:00 NZST, +12 -> +13
+        QCOMPARE(tran.atUtc,
+                 QDateTime(QDate(2012, 9, 30), QTime(2, 0), Qt::OffsetFromUTC, 12 * 3600));
+        QCOMPARE(tran.offsetFromUtc, 13 * 3600);
+        QCOMPARE(tran.standardTimeOffset, 12 * 3600);
         QCOMPARE(tran.daylightTimeOffset, 3600);
 
         tran = tz.previousTransition(jan);
-        QCOMPARE(tran.atUtc.toMSecsSinceEpoch(), (qint64)1316872800000);
-        QCOMPARE(tran.offsetFromUtc, 46800);
-        QCOMPARE(tran.standardTimeOffset, 43200);
+        // 2011-09-25 02:00 NZST, +12 -> +13
+        QCOMPARE(tran.atUtc,
+                 QDateTime(QDate(2011, 9, 25), QTime(2, 0), Qt::OffsetFromUTC, 12 * 3600));
+        QCOMPARE(tran.offsetFromUtc, 13 * 3600);
+        QCOMPARE(tran.standardTimeOffset, 12 * 3600);
         QCOMPARE(tran.daylightTimeOffset, 3600);
 
         tran = tz.previousTransition(jun);
-        QCOMPARE(tran.atUtc.toMSecsSinceEpoch(), (qint64)1333202400000);
-        QCOMPARE(tran.offsetFromUtc, 43200);
-        QCOMPARE(tran.standardTimeOffset, 43200);
+        // 2012-04-01 03:00 NZDT, +13 -> +12 (again)
+        QCOMPARE(tran.atUtc,
+                 QDateTime(QDate(2012, 4, 1), QTime(3, 0), Qt::OffsetFromUTC, 13 * 3600));
+        QCOMPARE(tran.offsetFromUtc, 12 * 3600);
+        QCOMPARE(tran.standardTimeOffset, 12 * 3600);
         QCOMPARE(tran.daylightTimeOffset, 0);
 
         QTimeZone::OffsetDataList expected;
-        tran.atUtc = QDateTime::fromMSecsSinceEpoch(1301752800000, Qt::UTC);
-        tran.offsetFromUtc = 46800;
-        tran.standardTimeOffset = 43200;
+        tran.atUtc = QDateTime(QDate(2011, 4, 3), QTime(2, 0), Qt::OffsetFromUTC, 13 * 3600);
+        tran.offsetFromUtc = 13 * 3600;
+        tran.standardTimeOffset = 12 * 3600;
         tran.daylightTimeOffset = 3600;
         expected << tran;
-        tran.atUtc = QDateTime::fromMSecsSinceEpoch(1316872800000, Qt::UTC);
-        tran.offsetFromUtc = 43200;
-        tran.standardTimeOffset = 43200;
+        tran.atUtc = QDateTime(QDate(2011, 9, 25), QTime(2, 0), Qt::OffsetFromUTC, 12 * 3600);
+        tran.offsetFromUtc = 12 * 3600;
+        tran.standardTimeOffset = 12 * 3600;
         tran.daylightTimeOffset = 0;
         expected << tran;
         QTimeZone::OffsetDataList result = tz.transitions(janPrev, jan);
@@ -845,7 +853,8 @@ void tst_QTimeZone::tzTest()
     }
 
     dat = tzp.nextTransition(-9999999999999);
-    QCOMPARE(dat.atMSecsSinceEpoch, (qint64)-2422054408000);
+    QCOMPARE(QDateTime::fromMSecsSinceEpoch(dat.atMSecsSinceEpoch, Qt::OffsetFromUTC, 3600),
+             QDateTime(QDate(1893, 4, 1), QTime(0, 6, 32), Qt::OffsetFromUTC, 3600));
     QCOMPARE(dat.standardTimeOffset, 3600);
     QCOMPARE(dat.daylightTimeOffset, 0);
 
@@ -855,37 +864,41 @@ void tst_QTimeZone::tzTest()
 
     // Tets high dates use the POSIX rule
     dat = tzp.data(stdHi);
-    QCOMPARE(dat.atMSecsSinceEpoch, (qint64)stdHi);
+    QCOMPARE(dat.atMSecsSinceEpoch - stdHi, (qint64)0);
     QCOMPARE(dat.offsetFromUtc, 3600);
     QCOMPARE(dat.standardTimeOffset, 3600);
     QCOMPARE(dat.daylightTimeOffset, 0);
 
     dat = tzp.data(dstHi);
-    QCOMPARE(dat.atMSecsSinceEpoch, (qint64)dstHi);
+    QCOMPARE(dat.atMSecsSinceEpoch - dstHi, (qint64)0);
     QCOMPARE(dat.offsetFromUtc, 7200);
     QCOMPARE(dat.standardTimeOffset, 3600);
     QCOMPARE(dat.daylightTimeOffset, 3600);
 
     dat = tzp.previousTransition(stdHi);
-    QCOMPARE(dat.atMSecsSinceEpoch, (qint64)4096659600000);
+    QCOMPARE(QDateTime::fromMSecsSinceEpoch(dat.atMSecsSinceEpoch, Qt::OffsetFromUTC, 3600),
+             QDateTime(QDate(2099, 10, 26), QTime(2, 0), Qt::OffsetFromUTC, 3600));
     QCOMPARE(dat.offsetFromUtc, 3600);
     QCOMPARE(dat.standardTimeOffset, 3600);
     QCOMPARE(dat.daylightTimeOffset, 0);
 
     dat = tzp.previousTransition(dstHi);
-    QCOMPARE(dat.atMSecsSinceEpoch, (qint64)4109965200000);
+    QCOMPARE(QDateTime::fromMSecsSinceEpoch(dat.atMSecsSinceEpoch, Qt::OffsetFromUTC, 3600),
+             QDateTime(QDate(2100, 3, 29), QTime(2, 0), Qt::OffsetFromUTC, 3600));
     QCOMPARE(dat.offsetFromUtc, 7200);
     QCOMPARE(dat.standardTimeOffset, 3600);
     QCOMPARE(dat.daylightTimeOffset, 3600);
 
     dat = tzp.nextTransition(stdHi);
-    QCOMPARE(dat.atMSecsSinceEpoch, (qint64)4109965200000);
+    QCOMPARE(QDateTime::fromMSecsSinceEpoch(dat.atMSecsSinceEpoch, Qt::OffsetFromUTC, 3600),
+             QDateTime(QDate(2100, 3, 29), QTime(2, 0), Qt::OffsetFromUTC, 3600));
     QCOMPARE(dat.offsetFromUtc, 7200);
     QCOMPARE(dat.standardTimeOffset, 3600);
     QCOMPARE(dat.daylightTimeOffset, 3600);
 
     dat = tzp.nextTransition(dstHi);
-    QCOMPARE(dat.atMSecsSinceEpoch, (qint64)4128109200000);
+    QCOMPARE(QDateTime::fromMSecsSinceEpoch(dat.atMSecsSinceEpoch, Qt::OffsetFromUTC, 3600),
+             QDateTime(QDate(2100, 10, 25), QTime(2, 0), Qt::OffsetFromUTC, 3600));
     QCOMPARE(dat.offsetFromUtc, 3600);
     QCOMPARE(dat.standardTimeOffset, 3600);
     QCOMPARE(dat.daylightTimeOffset, 0);
@@ -1076,36 +1089,48 @@ void tst_QTimeZone::testCetPrivate(const QTimeZonePrivate &tzp)
     // Only test transitions if host system supports them
     if (tzp.hasTransitions()) {
         QTimeZonePrivate::Data tran = tzp.nextTransition(std);
-        QCOMPARE(tran.atMSecsSinceEpoch, (qint64)1332637200000);
+        // 2012-03-25 02:00 CET, +1 -> +2
+        QCOMPARE(QDateTime::fromMSecsSinceEpoch(tran.atMSecsSinceEpoch, Qt::UTC),
+                 QDateTime(QDate(2012, 3, 25), QTime(2, 0), Qt::OffsetFromUTC, 3600));
         QCOMPARE(tran.offsetFromUtc, 7200);
         QCOMPARE(tran.standardTimeOffset, 3600);
         QCOMPARE(tran.daylightTimeOffset, 3600);
 
         tran = tzp.nextTransition(dst);
-        QCOMPARE(tran.atMSecsSinceEpoch, (qint64)1351386000000);
+        // 2012-10-28 03:00 CEST, +2 -> +1
+        QCOMPARE(QDateTime::fromMSecsSinceEpoch(tran.atMSecsSinceEpoch, Qt::UTC),
+                 QDateTime(QDate(2012, 10, 28), QTime(3, 0), Qt::OffsetFromUTC, 2 * 3600));
         QCOMPARE(tran.offsetFromUtc, 3600);
         QCOMPARE(tran.standardTimeOffset, 3600);
         QCOMPARE(tran.daylightTimeOffset, 0);
 
         tran = tzp.previousTransition(std);
-        QCOMPARE(tran.atMSecsSinceEpoch, (qint64)1319936400000);
+        // 2011-10-30 03:00 CEST, +2 -> +1
+        QCOMPARE(QDateTime::fromMSecsSinceEpoch(tran.atMSecsSinceEpoch, Qt::UTC),
+                 QDateTime(QDate(2011, 10, 30), QTime(3, 0), Qt::OffsetFromUTC, 2 * 3600));
         QCOMPARE(tran.offsetFromUtc, 3600);
         QCOMPARE(tran.standardTimeOffset, 3600);
         QCOMPARE(tran.daylightTimeOffset, 0);
 
         tran = tzp.previousTransition(dst);
-        QCOMPARE(tran.atMSecsSinceEpoch, (qint64)1332637200000);
+        // 2012-03-25 02:00 CET, +1 -> +2 (again)
+        QCOMPARE(QDateTime::fromMSecsSinceEpoch(tran.atMSecsSinceEpoch, Qt::UTC),
+                 QDateTime(QDate(2012, 3, 25), QTime(2, 0), Qt::OffsetFromUTC, 3600));
         QCOMPARE(tran.offsetFromUtc, 7200);
         QCOMPARE(tran.standardTimeOffset, 3600);
         QCOMPARE(tran.daylightTimeOffset, 3600);
 
         QTimeZonePrivate::DataList expected;
-        tran.atMSecsSinceEpoch = (qint64)1301187600000;
+        // 2011-03-27 02:00 CET, +1 -> +2
+        tran.atMSecsSinceEpoch = QDateTime(QDate(2011, 3, 27), QTime(2, 0),
+                                           Qt::OffsetFromUTC, 3600).toMSecsSinceEpoch();
         tran.offsetFromUtc = 7200;
         tran.standardTimeOffset = 3600;
         tran.daylightTimeOffset = 3600;
         expected << tran;
-        tran.atMSecsSinceEpoch = (qint64)1319936400000;
+        // 2011-10-30 03:00 CEST, +2 -> +1
+        tran.atMSecsSinceEpoch = QDateTime(QDate(2011, 10, 30), QTime(3, 0),
+                                           Qt::OffsetFromUTC, 2 * 3600).toMSecsSinceEpoch();
         tran.offsetFromUtc = 3600;
         tran.standardTimeOffset = 3600;
         tran.daylightTimeOffset = 0;
@@ -1113,7 +1138,10 @@ void tst_QTimeZone::testCetPrivate(const QTimeZonePrivate &tzp)
         QTimeZonePrivate::DataList result = tzp.transitions(prev, std);
         QCOMPARE(result.count(), expected.count());
         for (int i = 0; i < expected.count(); ++i) {
-            QCOMPARE(result.at(i).atMSecsSinceEpoch, expected.at(i).atMSecsSinceEpoch);
+            QCOMPARE(QDateTime::fromMSecsSinceEpoch(result.at(i).atMSecsSinceEpoch,
+                                                    Qt::OffsetFromUTC, 3600),
+                     QDateTime::fromMSecsSinceEpoch(expected.at(i).atMSecsSinceEpoch,
+                                                    Qt::OffsetFromUTC, 3600));
             QCOMPARE(result.at(i).offsetFromUtc, expected.at(i).offsetFromUtc);
             QCOMPARE(result.at(i).standardTimeOffset, expected.at(i).standardTimeOffset);
             QCOMPARE(result.at(i).daylightTimeOffset, expected.at(i).daylightTimeOffset);