Rework tst_QDateTime::toString_isoDate() to eliminate an XFAIL

Instead of an XFAIL, actually test what we expect will happen for the
test, namely that the milliseconds will be lost. In the process,
verify that milliseconds since epoch also matches what was expected,
change an "expecting empty" condition to check for the "invalid"
test-case to which it's actually relevant and note that this test-case
shall need amended when we update our ISODate support to the 2019
update, which extends the year range.

Task-number: QTBUG-56552
Change-Id: I680aa31ee0dcc8fadabb5d4cd6c083a8afd48573
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
(cherry picked from commit cc93dadf772480df3b27fd031a471047a5db0038)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 17 insertions, 16 deletions

diff --git a/tests/auto/corelib/time/qdatetime/tst_qdatetime.cpp b/tests/auto/corelib/time/qdatetime/tst_qdatetime.cpp
index 7f4520219f..7d924f5842 100644
--- a/tests/auto/corelib/time/qdatetime/tst_qdatetime.cpp
+++ b/tests/auto/corelib/time/qdatetime/tst_qdatetime.cpp
@@ -829,7 +829,7 @@ void tst_QDateTime::toString_isoDate_data()
     QTest::newRow("negative non-integral OffsetFromUTC")
             << dt << Qt::ISODate
             << QString("1978-11-09T13:28:34-00:15");
-    QTest::newRow("invalid")
+    QTest::newRow("invalid") // ISODate < 2019 doesn't allow -ve year numbers; QTBUG-91070
             << QDateTime(QDate(-1, 11, 9), QTime(13, 28, 34), Qt::UTC)
             << Qt::ISODate << QString();
     QTest::newRow("without-ms")
@@ -842,25 +842,26 @@ void tst_QDateTime::toString_isoDate_data()
 
 void tst_QDateTime::toString_isoDate()
 {
-    QFETCH(QDateTime, datetime);
-    QFETCH(Qt::DateFormat, format);
-    QFETCH(QString, expected);
+    QFETCH(const QDateTime, datetime);
+    QFETCH(const Qt::DateFormat, format);
+    QFETCH(const QString, expected);
 
-    QString result = datetime.toString(format);
+    const QString result = datetime.toString(format);
     QCOMPARE(result, expected);
 
-    QDateTime resultDatetime = QDateTime::fromString(result, format);
-    // If expecting invalid result the datetime may still be valid, i.e. year < 0 or > 9999
-    if (!expected.isEmpty()) {
-        QEXPECT_FAIL("without-ms", "Qt::ISODate truncates milliseconds (QTBUG-56552)", Abort);
-
-        QCOMPARE(resultDatetime, datetime);
-        QCOMPARE(resultDatetime.date(), datetime.date());
-        QCOMPARE(resultDatetime.time(), datetime.time());
-        QCOMPARE(resultDatetime.timeSpec(), datetime.timeSpec());
-        QCOMPARE(resultDatetime.offsetFromUtc(), datetime.offsetFromUtc());
-    } else {
+    const QDateTime resultDatetime = QDateTime::fromString(result, format);
+    if (QByteArrayView(QTest::currentDataTag()) == "invalid") {
         QCOMPARE(resultDatetime, QDateTime());
+    } else {
+        const QDateTime when =
+            QByteArrayView(QTest::currentDataTag()) == "without-ms"
+            ? datetime.addMSecs(-datetime.time().msec()) : datetime;
+        QCOMPARE(resultDatetime.toMSecsSinceEpoch(), when.toMSecsSinceEpoch());
+        QCOMPARE(resultDatetime, when);
+        QCOMPARE(resultDatetime.date(), when.date());
+        QCOMPARE(resultDatetime.time(), when.time());
+        QCOMPARE(resultDatetime.timeSpec(), when.timeSpec());
+        QCOMPARE(resultDatetime.offsetFromUtc(), when.offsetFromUtc());
     }
 }