Partial fix DateTime UTC/Local in index key litedb-org#921

LiteDB.Tests/Database/DateTimeMinMax_Tests.cs

@@ -0,0 +1,79 @@
+using System;
+using System.IO;
+using System.Linq;
+using LiteDB;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace LiteDBDateTimeIndexMinMax
+{
+    #region Model
+
+    public class DateTimeTest
+    {
+        public int Id { get; set; }
+        public DateTime? Date { get; set; }
+    }
+
+    #endregion
+
+    [TestClass]
+    public class DateTimeMinMax_Tests
+    {
+        [TestMethod]
+        public void DateTimeMinMax_Test()
+        {
+            var memory = new MemoryStream();
+
+            using (var db = new LiteDatabase(memory))
+            {
+                var col = db.GetCollection<DateTimeTest>();
+                col.EnsureIndex(x => x.Date);
+
+                col.Insert(new DateTimeTest() { Id = 1, Date = new DateTime(2018, 02, 22, 0, 0, 0) });
+                col.Insert(new DateTimeTest() { Id = 2, Date = new DateTime(2018, 02, 22, 23, 59, 59) });
+
+                MinMaxCommon(col);
+            }
+
+            using (var db = new LiteDatabase(memory))
+            {
+                var col = db.GetCollection<DateTimeTest>();
+
+                MinMaxCommon(col);
+
+                col.Insert(new DateTimeTest() { Id = 3, Date = new DateTime(2018, 02, 21, 23, 59, 59) });
+                col.Insert(new DateTimeTest() { Id = 4, Date = new DateTime(2018, 02, 23, 0, 0, 0) });
+                col.Insert(new DateTimeTest() { Id = 5, Date = new DateTime(2018, 02, 22, 0, 0, 1) });
+                col.Insert(new DateTimeTest() { Id = 6, Date = new DateTime(2018, 02, 22, 23, 59, 58) });
+
+                MinMaxCommon(col);
+            }
+
+            using (var db = new LiteDatabase(memory))
+            {
+                var col = db.GetCollection<DateTimeTest>();
+
+                MinMaxCommon(col);
+            }
+        }
+
+        private void MinMaxCommon(LiteCollection<DateTimeTest> coll)
+        {
+            var searchdatetime = new DateTime(2018, 02, 22, 0, 0, 10);
+
+            var min = coll.Min(x => x.Date).AsDateTime;
+            var max = coll.Max(x => x.Date).AsDateTime;
+
+            var smaller = coll.FindOne(x => x.Date < searchdatetime);
+            var greater = coll.FindOne(x => x.Date > searchdatetime);
+
+            var all = coll.FindAll().ToList();
+
+            var linqmin = all.Min(x => x.Date);
+            var linqmax = all.Max(x => x.Date);
+
+            Assert.AreEqual(min, linqmin);
+            Assert.AreEqual(max, linqmax);
+        }
+    }
+}

LiteDB/Utils/ByteReader.cs

@@ -129,7 +129,12 @@ public string ReadString(int length)
 
         public DateTime ReadDateTime()
         {
-            return new DateTime(this.ReadInt64(), DateTimeKind.Utc);
+            // fix #921 converting index key into LocalTime
+            // this is not best solution because uctDate must be a global parameter
+            // this will be review in v5
+            var date = new DateTime(this.ReadInt64(), DateTimeKind.Utc);
+
+            return date.ToLocalTime();
         }
 
         public Guid ReadGuid()