From 0857f815af6d6a0c1d9400effa115f52347587df Mon Sep 17 00:00:00 2001
From: Pisotskyi Pavel <ppis@isd.dp.ua>
Date: Thu, 18 Jan 2024 14:14:09 +0200
Subject: [PATCH] The getDate() method returns 0 for December 31st before 1970.

---
 Jint.Tests/Runtime/DateTests.cs   | 21 +++++++++++++++++++++
 Jint/Native/Date/DatePrototype.cs |  2 +-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/Jint.Tests/Runtime/DateTests.cs b/Jint.Tests/Runtime/DateTests.cs
index 3ac6b9e16d..1698b2871f 100644
--- a/Jint.Tests/Runtime/DateTests.cs
+++ b/Jint.Tests/Runtime/DateTests.cs
@@ -104,6 +104,27 @@ public void CanParseLocaleString(string input, long expected)
         Assert.Equal(expected, _engine.Evaluate($"new Date('{input}') * 1").AsNumber());
     }
 
+    [Theory]
+    [InlineData("December 31 1900 12:00:00 +0300", 31)]
+    [InlineData("January 1 1969 12:00:00 +0300", 1)]
+    [InlineData("December 31 1969 12:00:00 +0300", 31)]
+    [InlineData("January 1 1970 12:00:00 +0300", 1)]
+    [InlineData("December 31 1970 12:00:00 +0300", 31)]
+    public void CanParseDate(string input, int expectedDate)
+    {
+        TimeZoneInfo timeZoneInfo;
+        try
+        {
+            timeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById("Europe/Kiev");
+        }
+        catch
+        {
+            timeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById("FLE Standard Time");
+        }
+        var engine = new Engine(options => options.LocalTimeZone(timeZoneInfo));
+        Assert.Equal(expectedDate, _engine.Evaluate($"new Date('{input}').getDate()").AsNumber());
+    }
+
     [Fact]
     public void CanUseMoment()
     {
diff --git a/Jint/Native/Date/DatePrototype.cs b/Jint/Native/Date/DatePrototype.cs
index 5427d34794..e2fbf53bfb 100644
--- a/Jint/Native/Date/DatePrototype.cs
+++ b/Jint/Native/Date/DatePrototype.cs
@@ -1270,7 +1270,7 @@ private static bool AreFinite(double value1, double value2, double value3, doubl
 
         private static readonly int[] kDaysInMonths = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
 
-        private static Date YearMonthDayFromTime(DatePresentation t) => YearMonthDayFromDays(t.Value / 1000 / 60 / 60 / 24);
+        private static Date YearMonthDayFromTime(DatePresentation t) => YearMonthDayFromDays((long) System.Math.Floor(t.Value / 1000 / 60 / 60 / 24d));
 
         private static Date YearMonthDayFromDays(long days)
         {