Add test to verify that fileset file exists after repair.

This test would have failed prior to the changes in revision 0cfce6b
("Include fileset file when repairing missing dlist file").

This concerns issue duplicati#3982.

Duplicati/UnitTest/DisruptionTests.cs

@@ -115,6 +115,29 @@ public async Task FilesetFiles()
             Assert.AreEqual(2, backupTypes.Length);
             Assert.AreEqual(BackupType.FULL_BACKUP, backupTypes[1]);
             Assert.AreEqual(BackupType.PARTIAL_BACKUP, backupTypes[0]);
+
+            // Remove the dlist files.
+            foreach (string dlistFile in dlistFiles)
+            {
+                File.Delete(dlistFile);
+            }
+
+            // Run a repair and verify that the fileset file exists in the new dlist files.
+            using (Controller c = new Controller("file://" + this.TARGETFOLDER, options, null))
+            {
+                c.Repair();
+                List<IListResultFileset> filesets = c.List().Filesets.ToList();
+                Assert.AreEqual(2, filesets.Count);
+                Assert.AreEqual(BackupType.FULL_BACKUP, filesets.Single(x => x.Version == 1).IsFullBackup);
+                Assert.AreEqual(BackupType.PARTIAL_BACKUP, filesets.Single(x => x.Version == 0).IsFullBackup);
+
+                backupTypeMap = GetBackupTypesFromRemoteFiles(c, out _);
+            }
+
+            backupTypes = backupTypeMap.OrderByDescending(x => x.Key).Select(x => x.Value).ToArray();
+            Assert.AreEqual(2, backupTypes.Length);
+            Assert.AreEqual(BackupType.FULL_BACKUP, backupTypes[1]);
+            Assert.AreEqual(BackupType.PARTIAL_BACKUP, backupTypes[0]);
         }
 
         [Test]