Be more fussy about the MakeDay() calculation

The ES Date spec goes into minute detail about doing various
algorithms in the dumbest possible way (like InLeapYear() calling
DaysInYear(), rather than the other way round) but, in MakeDay(),
leaves the implementation to solve the problem of finding the start of
the first day of a specified month in a given year. So exercise the
freedom we have in that to be a little more robust; and actually check
we have met the conditions the spec requires, returning NaN (as
specified) if not.

Added tests for some denormal dates and date-times and for a date
mentioned in QTBUG-78996.

Task-number: QTBUG-78996
Change-Id: I8d9a841dd1f1d9995273a3de8f6f9130207c7c2b
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/tests/auto/qml/qqmlecmascript/data/checkDate-denormal-leap.qml b/tests/auto/qml/qqmlecmascript/data/checkDate-denormal-leap.qml
new file mode 100644
index 0000000000..6dd84810e6
--- /dev/null
+++ b/tests/auto/qml/qqmlecmascript/data/checkDate-denormal-leap.qml
@@ -0,0 +1,11 @@
+import Qt.test 1.0
+import QtQuick 2.0
+
+MyTypeObject {
+    Component.onCompleted: {
+        dateProperty = new Date(2020, 2, 0) // Feb 29th
+        boolProperty = (dateProperty.getFullYear() == 2020
+                        && dateProperty.getMonth() == 1
+                        && dateProperty.getDate() == 29)
+    }
+}