CSHARP-945: Throw ArgumentOutOfRangeException when ObjectId constructor is passed a DateTime that is out of range.

Author: rstam

src/MongoDB.Bson.Tests/ObjectModel/ObjectIdTests.cs

@@ -107,6 +107,23 @@ public void TestDateTimeConstructor()
             Assert.IsTrue(bytes.SequenceEqual(objectId.ToByteArray()));
         }
 
+        [TestCase(int.MinValue)]
+        [TestCase(int.MaxValue)]
+        public void TestDateTimeConstructorAtEdgeOfRange(int secondsSinceEpoch)
+        {
+            var timestamp = BsonConstants.UnixEpoch.AddSeconds(secondsSinceEpoch);
+            var objectId = new ObjectId(timestamp, 0, 0, 0);
+            Assert.AreEqual(timestamp, objectId.CreationTime);
+        }
+
+        [TestCase((long)int.MinValue - 1)]
+        [TestCase((long)int.MaxValue + 1)]
+        public void TestDateTimeConstructorArgumentOutOfRangeException(long secondsSinceEpoch)
+        {
+            var timestamp = BsonConstants.UnixEpoch.AddSeconds(secondsSinceEpoch);
+            Assert.Throws<ArgumentOutOfRangeException>(() => new ObjectId(timestamp, 0, 0, 0));
+        }
+
         [Test]
         public void TestStringConstructor()
         {

src/MongoDB.Bson/ObjectModel/ObjectId.cs

@@ -409,7 +409,12 @@ private static int GetMachineHash()
 
         private static int GetTimestampFromDateTime(DateTime timestamp)
         {
-            return (int)Math.Floor((BsonUtils.ToUniversalTime(timestamp) - BsonConstants.UnixEpoch).TotalSeconds);
+            var secondsSinceEpoch = (long)Math.Floor((BsonUtils.ToUniversalTime(timestamp) - BsonConstants.UnixEpoch).TotalSeconds);
+            if (secondsSinceEpoch < int.MinValue || secondsSinceEpoch > int.MaxValue)
+            {
+                throw new ArgumentOutOfRangeException("timestamp");
+            }
+            return (int)secondsSinceEpoch;
         }
 
         // public methods