Add a test and remove a work-around for a fixed bug

The ASN.1 parser for a date-time had to check the date-time string was
all digits to catch the case of a sign in the month field, which used
to be accepted when it should not be. That bug has now been fixed, so
remove the work-around and add a second date-time test-case, renaming
(and modernising) the existing one for consistency.

Task-number: QTBUG-84349
Change-Id: I649c5129312b6865af08b22ba6893cb4e29243f8
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>

src/plugins/tls/shared/qasn1element.cpp

@@ -261,13 +261,6 @@ QDateTime QAsn1Element::toDateTime() const
     if (mValue.back() != 'Z')
         return result;
 
-    // In addition, check that we only have digits representing the
-    // date/time. This should not really be necessary (there's no such
-    // thing as negative months/days/etc.); it's a workaround for
-    // QTBUG-84349.
-    if (!std::all_of(mValue.begin(), mValue.end() - 1, isAsciiDigit))
-        return result;
-
     if (mType == UtcTimeType && mValue.size() == 13) {
         result = QDateTime::fromString(QString::fromLatin1(mValue),
                                        QStringLiteral("yyMMddHHmmsst"));

tests/auto/corelib/time/qdatetime/tst_qdatetime.cpp

@@ -2908,10 +2908,11 @@ void tst_QDateTime::fromStringStringFormat_data()
         << QString(u8"yyyy🤣MM🤣ddThh🤣mm🤣ss.zt")
         << QDateTime(QDate(2005, 6, 28), QTime(7, 57, 30, 1), Qt::UTC);
 
-    // QTBUG-84349
-    QTest::newRow("QTBUG-84349: positive sign in month")
-            << QStringLiteral("9922+221102233Z") << QStringLiteral("yyyyMMddHHmmsst")
-            << QDateTime();
+    // Two tests derived from malformed ASN.1 strings (QTBUG-84349):
+    QTest::newRow("ASN.1:UTC")
+        << u"22+221102233Z"_qs << u"yyMMddHHmmsst"_qs << QDateTime();
+    QTest::newRow("ASN.1:Generalized")
+        << u"9922+221102233Z"_qs << u"yyyyMMddHHmmsst"_qs << QDateTime();
 
     // fuzzer test
     QTest::newRow("integer overflow found by fuzzer")