Directory write time is now calculated based on the most recent file write to any file inside of that directory.

NzbDrone.Common.Test/DiskProviderFixture.cs

@@ -1,5 +1,6 @@
 // ReSharper disable InconsistentNaming
 
+using System;
 using System.IO;
 using System.Linq;
 using FluentAssertions;
@@ -151,6 +152,29 @@ namespace NzbDrone.Common.Test
             DiskProvider.PathEquals(first, second).Should().BeFalse();
         }
 
+        [Test]
+        public void empty_folder_should_return_folder_modified_date()
+        {
+            var tempfolder = new DirectoryInfo(TempFolder);
+            Mocker.Resolve<DiskProvider>().GetLastDirectoryWrite(TempFolder).Should().Be(tempfolder.LastWriteTimeUtc);
+        }
+
+        [Test]
+        public void folder_should_return_correct_value_for_last_write()
+        {
+            var appPath = new EnviromentProvider().ApplicationPath;
+            Mocker.Resolve<DiskProvider>().GetLastDirectoryWrite(appPath).Should().BeOnOrAfter(DateTime.UtcNow.AddMinutes(-10));
+            Mocker.Resolve<DiskProvider>().GetLastDirectoryWrite(appPath).Should().BeBefore(DateTime.UtcNow);
+        }
+
+        [Test]
+        [Explicit]
+        public void check_last_write()
+        {
+           Console.WriteLine(Mocker.Resolve<DiskProvider>().GetLastDirectoryWrite(@"C:\DRIVERS"));
+           Console.WriteLine(new DirectoryInfo(@"C:\DRIVERS").LastWriteTimeUtc);
+        }
+
         private void VerifyCopy()
         {
             BinFolder.Refresh();

NzbDrone.Common/DiskProvider.cs

@@ -31,7 +31,15 @@ namespace NzbDrone.Common
                 throw new DirectoryNotFoundException("Directory doesn't exist. " + path);
             }
 
-            GetFiles(path, SearchOption.AllDirectories);
+            var dirFiles = GetFiles(path, SearchOption.AllDirectories).ToList();
+
+            if (!dirFiles.Any())
+            {
+                return new DirectoryInfo(path).LastWriteTimeUtc;
+            }
+
+            return dirFiles.Select(f => new FileInfo(f))
+                            .Max(c => c.LastWriteTimeUtc);
         }
 
         public virtual bool FolderExists(string path)

NzbDrone.Core.Test/ProviderTests/PostDownloadProviderTests/ProcessDownloadProviderFixture.cs

@@ -20,10 +20,26 @@ namespace NzbDrone.Core.Test.ProviderTests.PostDownloadProviderTests
     [TestFixture]
     public class ProcessDownloadProviderFixture : CoreTest
     {
+
+        private void WithOldWrite()
+        {
+            Mocker.GetMock<DiskProvider>()
+                .Setup(c => c.GetLastDirectoryWrite(It.IsAny<String>()))
+                .Returns(DateTime.Now.AddDays(-5));
+        }
+
+        private void WithRecentWrite()
+        {
+            Mocker.GetMock<DiskProvider>()
+                .Setup(c => c.GetLastDirectoryWrite(It.IsAny<String>()))
+                .Returns(DateTime.UtcNow);
+        }
+
         [Test]
         public void should_skip_if_folder_is_tagged_and_too_fresh()
         {
             WithStrictMocker();
+            WithRecentWrite();
 
             var droppedFolder = new DirectoryInfo(TempFolder + "\\_test\\");
             droppedFolder.Create();
@@ -34,11 +50,11 @@ namespace NzbDrone.Core.Test.ProviderTests.PostDownloadProviderTests
         [Test]
         public void should_continue_processing_if_folder_is_tagged_and_not_fresh()
         {
+            WithOldWrite();
+
             var droppedFolder = new DirectoryInfo(TempFolder + "\\_test\\");
             droppedFolder.Create();
 
-            droppedFolder.LastWriteTime = DateTime.Now.AddMinutes(-2);
-
             //Act
             Mocker.GetMock<SeriesProvider>().Setup(s => s.FindSeries(It.IsAny<String>())).Returns<Series>(null).Verifiable();
             Mocker.Resolve<PostDownloadProvider>().ProcessDownload(droppedFolder);
@@ -52,6 +68,8 @@ namespace NzbDrone.Core.Test.ProviderTests.PostDownloadProviderTests
         [Test]
         public void should_search_for_series_using_title_without_status()
         {
+            WithOldWrite();
+
             var droppedFolder = new DirectoryInfo(@"C:\Test\Unsorted TV\_unpack_The Office - S01E01 - Episode Title");
 
             Mocker.GetMock<SeriesProvider>().Setup(s => s.FindSeries("office")).Returns<Series>(null).Verifiable();
@@ -70,6 +88,7 @@ namespace NzbDrone.Core.Test.ProviderTests.PostDownloadProviderTests
         {
             //Setup
             WithStrictMocker();
+            WithOldWrite();
             var droppedFolder = new DirectoryInfo(@"C:\Test\Unsorted TV\The Office - S01E01 - Episode Title");
 
             var taggedFolder = @"C:\Test\Unsorted TV\_UnknownSeries_The Office - S01E01 - Episode Title";
@@ -91,6 +110,7 @@ namespace NzbDrone.Core.Test.ProviderTests.PostDownloadProviderTests
         {
             //Setup
             WithStrictMocker();
+            WithOldWrite();
             var droppedFolder = new DirectoryInfo(@"C:\Test\Unsorted TV\The Office - S01E01 - Episode Title");
 
             var taggedFolder = @"C:\Test\Unsorted TV\_ParseError_The Office - S01E01 - Episode Title";
@@ -120,6 +140,7 @@ namespace NzbDrone.Core.Test.ProviderTests.PostDownloadProviderTests
         {
             //Setup
             WithStrictMocker();
+            WithOldWrite();
             var droppedFolder = new DirectoryInfo(@"C:\Test\Unsorted TV\The Office - Season 01");
 
             var taggedFolder = PostDownloadProvider.GetTaggedFolderName(droppedFolder, PostDownloadStatusType.Unknown);
@@ -154,10 +175,10 @@ namespace NzbDrone.Core.Test.ProviderTests.PostDownloadProviderTests
         public void folder_shouldnt_be_tagged_with_same_tag_again(string path)
         {
             //Setup
-            
+
             var droppedFolder = new DirectoryInfo(TempFolder + path);
             droppedFolder.Create();
-            droppedFolder.LastWriteTime = DateTime.Now.AddHours(-1);
+            WithOldWrite();
 
             //Act
             Mocker.GetMock<SeriesProvider>().Setup(s => s.FindSeries(It.IsAny<String>())).Returns<Series>(null);
@@ -172,7 +193,7 @@ namespace NzbDrone.Core.Test.ProviderTests.PostDownloadProviderTests
         public void folder_should_not_be_tagged_if_existing_tag_is_diffrent()
         {
             //Setup
-            
+            WithOldWrite();
             var droppedFolder = new DirectoryInfo(TempFolder + @"\_UnknownEpisode_The Office - S01E01 - Episode Title");
             droppedFolder.Create();
             droppedFolder.LastWriteTime = DateTime.Now.AddHours(-1);

NzbDrone.Core/Providers/PostDownloadProvider.cs

@@ -50,7 +50,7 @@ namespace NzbDrone.Core.Providers
 
         public virtual void ProcessDownload(DirectoryInfo subfolderInfo)
         {
-            if (subfolderInfo.Name.StartsWith("_") && subfolderInfo.LastWriteTimeUtc.AddMinutes(1) > DateTime.UtcNow)
+            if (subfolderInfo.Name.StartsWith("_") && _diskProvider.GetLastDirectoryWrite(subfolderInfo.FullName).AddMinutes(2) > DateTime.UtcNow)
             {
                 Logger.Trace("[{0}] is too fresh. skipping", subfolderInfo.Name);
                 return;