Fix DateTime handling in Storage.cs and add hitl.db to OptunaTests.cs…

…proj

Optuna/Storage/RDB/Storage.cs

@@ -441,13 +441,14 @@ public Trial.Trial GetTrial(int trialId)
                     {
                         while (reader.Read())
                         {
+                            DateTime completeTime = reader.GetValue(3) is DBNull ? DateTime.MaxValue : reader.GetDateTime(3);
                             trial = new Trial.Trial
                             {
                                 TrialId = trialId,
                                 Number = reader.GetInt32(0),
                                 State = (TrialState)Enum.Parse(typeof(TrialState), reader.GetString(1), true),
                                 DatetimeStart = reader.GetDateTime(2),
-                                DatetimeComplete = reader.GetDateTime(3)
+                                DatetimeComplete = completeTime
                             };
                         }
                     }

OptunaTests/OptunaTests.csproj

@@ -27,6 +27,9 @@
     <None Update="TestFile\sqlite.db">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
+    <None Update="TestFile\hitl.db">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
   </ItemGroup>
 
 </Project>

OptunaTests/Storage/RDB/StorageTests.cs

@@ -13,6 +13,7 @@ public class SqliteStorageTests : IClassFixture<CreateStorage>, IDisposable
     {
         private readonly string _createFilePath = @"TestFile/created.db";
         private readonly string _existFilePath = @"TestFile/sqlite.db";
+        private readonly string _hitlFilePath = @"TestFile/hitl.db";
         private readonly List<string> _tempDBPaths = new List<string>();
 
         [Fact()]
@@ -86,6 +87,15 @@ public void GetAllStudiesTest()
             Assert.Equal(3, studies.Length);
         }
 
+        [Fact()]
+        public void LoadHitlDBTest()
+        {
+            var storage = new SqliteStorage(_hitlFilePath);
+            Study.Study[] study = storage.GetAllStudies();
+            Assert.Single(study);
+            Assert.Equal(DateTime.MinValue, study[0].Trials[0].DatetimeComplete);
+        }
+
         public void Dispose()
         {
             foreach (string path in _tempDBPaths)