[#579] Timestamp encoding precision

Author: xinchen10

src/Types/Encoder.cs

@@ -383,11 +383,21 @@ public static void AddKnownDescribed(Descriptor descriptor, CreateDescribed ctor
         /// <returns></returns>
         public static long DateTimeToTimestamp(DateTime dateTime)
         {
-#if (NANOFRAMEWORK_1_0)
-            return (long)((dateTime.Ticks - epochTicks) / TicksPerMillisecond);
-#else
-            return (long)((dateTime.ToUniversalTime().Ticks - epochTicks) / TicksPerMillisecond);
+            DateTime utc = dateTime;
+#if !NANOFRAMEWORK_1_0
+            if (dateTime.Kind == DateTimeKind.Local)
+            {
+                utc = dateTime.ToUniversalTime();
+            }
 #endif
+            long ticks = utc.Ticks - epochTicks;
+            long ms = ticks / TicksPerMillisecond;
+            long remainder = ticks % TicksPerMillisecond;
+            if (remainder >= TicksPerMillisecond / 2)
+            {
+                ms++;
+            }
+            return ms;
         }
 
         /// <summary>

test/Test.Amqp.Net/AmqpCodecTests.cs

@@ -282,6 +282,22 @@ public void AmqpCodecListTest()
             EnsureEqual((IList)described.Value, (IList)described4.Value);
         }
 
+        [TestMethod()]
+        public void AmqpCodecTimestampTest()
+        {
+            DateTime now = DateTime.UtcNow;
+            now = new DateTime(now.Year, now.Month, now.Day, now.Hour, now.Minute, now.Second, now.Millisecond, DateTimeKind.Utc);
+            long ms = Encoder.DateTimeToTimestamp(now);
+            DateTime value = Encoder.TimestampToDateTime(ms);
+            Assert.AreEqual(now, value);
+
+            value = Encoder.TimestampToDateTime(Encoder.DateTimeToTimestamp(DateTime.MaxValue));
+            Assert.AreEqual(DateTime.MaxValue, value);
+
+            value = Encoder.TimestampToDateTime(Encoder.DateTimeToTimestamp(DateTime.MinValue));
+            Assert.AreEqual(DateTime.MinValue, value);
+        }
+
         [TestMethod()]
         public void AmqpCodecTimestampRangeTest()
         {
@@ -839,7 +855,7 @@ static void EnsureEqual(Map map1, Map map2)
 
         static void EnsureEqual(DateTime d1, DateTime d2)
         {
-            Assert.IsTrue(Math.Abs((d1.ToUniversalTime() - d2.ToUniversalTime()).TotalMilliseconds) < 5, "Datetime difference is greater than 5ms.");
+            Assert.IsTrue(Math.Abs((d1 - d2).TotalMilliseconds) < 5, "Datetime difference is greater than 5ms.");
         }
 
         static void EnsureEqual(object x, object y)