/// <summary>for normal (non-snapshot) file.</summary>
        /// <exception cref="System.Exception"/>
        public virtual void TestNonSnapshotPathINodes()
        {
            // Get the inodes by resolving the path of a normal file
            string[]     names       = INode.GetPathNames(file1.ToString());
            byte[][]     components  = INode.GetPathComponents(names);
            INodesInPath nodesInPath = INodesInPath.Resolve(fsdir.rootDir, components, false);

            // The number of inodes should be equal to components.length
            NUnit.Framework.Assert.AreEqual(nodesInPath.Length(), components.Length);
            // The returned nodesInPath should be non-snapshot
            AssertSnapshot(nodesInPath, false, null, -1);
            // The last INode should be associated with file1
            NUnit.Framework.Assert.IsTrue("file1=" + file1 + ", nodesInPath=" + nodesInPath,
                                          nodesInPath.GetINode(components.Length - 1) != null);
            NUnit.Framework.Assert.AreEqual(nodesInPath.GetINode(components.Length - 1).GetFullPathName
                                                (), file1.ToString());
            NUnit.Framework.Assert.AreEqual(nodesInPath.GetINode(components.Length - 2).GetFullPathName
                                                (), sub1.ToString());
            NUnit.Framework.Assert.AreEqual(nodesInPath.GetINode(components.Length - 3).GetFullPathName
                                                (), dir.ToString());
            nodesInPath = INodesInPath.Resolve(fsdir.rootDir, components, false);
            NUnit.Framework.Assert.AreEqual(nodesInPath.Length(), components.Length);
            AssertSnapshot(nodesInPath, false, null, -1);
            NUnit.Framework.Assert.AreEqual(nodesInPath.GetLastINode().GetFullPathName(), file1
                                            .ToString());
        }
        /// <summary>for snapshot file after deleting the original file.</summary>
        /// <exception cref="System.Exception"/>
        public virtual void TestSnapshotPathINodesAfterDeletion()
        {
            // Create a snapshot for the dir, and check the inodes for the path
            // pointing to a snapshot file
            hdfs.AllowSnapshot(sub1);
            hdfs.CreateSnapshot(sub1, "s2");
            // Delete the original file /TestSnapshot/sub1/file1
            hdfs.Delete(file1, false);
            Org.Apache.Hadoop.Hdfs.Server.Namenode.Snapshot.Snapshot snapshot;
            {
                // Resolve the path for the snapshot file
                // /TestSnapshot/sub1/.snapshot/s2/file1
                string       snapshotPath = sub1.ToString() + "/.snapshot/s2/file1";
                string[]     names        = INode.GetPathNames(snapshotPath);
                byte[][]     components   = INode.GetPathComponents(names);
                INodesInPath nodesInPath  = INodesInPath.Resolve(fsdir.rootDir, components, false);
                // Length of inodes should be (components.length - 1), since we will ignore
                // ".snapshot"
                NUnit.Framework.Assert.AreEqual(nodesInPath.Length(), components.Length - 1);
                // SnapshotRootIndex should be 3: {root, Testsnapshot, sub1, s2, file1}
                snapshot = GetSnapshot(nodesInPath, "s2", 3);
                AssertSnapshot(nodesInPath, true, snapshot, 3);
                // Check the INode for file1 (snapshot file)
                INode inode = nodesInPath.GetLastINode();
                NUnit.Framework.Assert.AreEqual(file1.GetName(), inode.GetLocalName());
                NUnit.Framework.Assert.IsTrue(inode.AsFile().IsWithSnapshot());
            }
            // Check the INodes for path /TestSnapshot/sub1/file1
            string[]     names_1       = INode.GetPathNames(file1.ToString());
            byte[][]     components_1  = INode.GetPathComponents(names_1);
            INodesInPath nodesInPath_1 = INodesInPath.Resolve(fsdir.rootDir, components_1, false
                                                              );

            // The length of inodes should be equal to components.length
            NUnit.Framework.Assert.AreEqual(nodesInPath_1.Length(), components_1.Length);
            // The number of non-null elements should be components.length - 1 since
            // file1 has been deleted
            NUnit.Framework.Assert.AreEqual(GetNumNonNull(nodesInPath_1), components_1.Length
                                            - 1);
            // The returned nodesInPath should be non-snapshot
            AssertSnapshot(nodesInPath_1, false, snapshot, -1);
            // The last INode should be null, and the one before should be associated
            // with sub1
            NUnit.Framework.Assert.IsNull(nodesInPath_1.GetINode(components_1.Length - 1));
            NUnit.Framework.Assert.AreEqual(nodesInPath_1.GetINode(components_1.Length - 2).GetFullPathName
                                                (), sub1.ToString());
            NUnit.Framework.Assert.AreEqual(nodesInPath_1.GetINode(components_1.Length - 3).GetFullPathName
                                                (), dir.ToString());
            hdfs.DeleteSnapshot(sub1, "s2");
            hdfs.DisallowSnapshot(sub1);
        }
        /// <summary>for snapshot file while adding a new file after snapshot.</summary>
        /// <exception cref="System.Exception"/>
        public virtual void TestSnapshotPathINodesWithAddedFile()
        {
            // Create a snapshot for the dir, and check the inodes for the path
            // pointing to a snapshot file
            hdfs.AllowSnapshot(sub1);
            hdfs.CreateSnapshot(sub1, "s4");
            // Add a new file /TestSnapshot/sub1/file3
            Path file3 = new Path(sub1, "file3");

            DFSTestUtil.CreateFile(hdfs, file3, 1024, Replication, seed);
            Org.Apache.Hadoop.Hdfs.Server.Namenode.Snapshot.Snapshot s4;
            {
                // Check the inodes for /TestSnapshot/sub1/.snapshot/s4/file3
                string       snapshotPath = sub1.ToString() + "/.snapshot/s4/file3";
                string[]     names        = INode.GetPathNames(snapshotPath);
                byte[][]     components   = INode.GetPathComponents(names);
                INodesInPath nodesInPath  = INodesInPath.Resolve(fsdir.rootDir, components, false);
                // Length of inodes should be (components.length - 1), since we will ignore
                // ".snapshot"
                NUnit.Framework.Assert.AreEqual(nodesInPath.Length(), components.Length - 1);
                // The number of non-null inodes should be components.length - 2, since
                // snapshot of file3 does not exist
                NUnit.Framework.Assert.AreEqual(GetNumNonNull(nodesInPath), components.Length - 2
                                                );
                s4 = GetSnapshot(nodesInPath, "s4", 3);
                // SnapshotRootIndex should still be 3: {root, Testsnapshot, sub1, s4, null}
                AssertSnapshot(nodesInPath, true, s4, 3);
                // Check the last INode in inodes, which should be null
                NUnit.Framework.Assert.IsNull(nodesInPath.GetINode(nodesInPath.Length() - 1));
            }
            // Check the inodes for /TestSnapshot/sub1/file3
            string[]     names_1       = INode.GetPathNames(file3.ToString());
            byte[][]     components_1  = INode.GetPathComponents(names_1);
            INodesInPath nodesInPath_1 = INodesInPath.Resolve(fsdir.rootDir, components_1, false
                                                              );

            // The number of inodes should be equal to components.length
            NUnit.Framework.Assert.AreEqual(nodesInPath_1.Length(), components_1.Length);
            // The returned nodesInPath should be non-snapshot
            AssertSnapshot(nodesInPath_1, false, s4, -1);
            // The last INode should be associated with file3
            NUnit.Framework.Assert.AreEqual(nodesInPath_1.GetINode(components_1.Length - 1).GetFullPathName
                                                (), file3.ToString());
            NUnit.Framework.Assert.AreEqual(nodesInPath_1.GetINode(components_1.Length - 2).GetFullPathName
                                                (), sub1.ToString());
            NUnit.Framework.Assert.AreEqual(nodesInPath_1.GetINode(components_1.Length - 3).GetFullPathName
                                                (), dir.ToString());
            hdfs.DeleteSnapshot(sub1, "s4");
            hdfs.DisallowSnapshot(sub1);
        }
        /// <summary>for snapshot file while modifying file after snapshot.</summary>
        /// <exception cref="System.Exception"/>
        public virtual void TestSnapshotPathINodesAfterModification()
        {
            // First check the INode for /TestSnapshot/sub1/file1
            string[]     names       = INode.GetPathNames(file1.ToString());
            byte[][]     components  = INode.GetPathComponents(names);
            INodesInPath nodesInPath = INodesInPath.Resolve(fsdir.rootDir, components, false);

            // The number of inodes should be equal to components.length
            NUnit.Framework.Assert.AreEqual(nodesInPath.Length(), components.Length);
            // The last INode should be associated with file1
            NUnit.Framework.Assert.AreEqual(nodesInPath.GetINode(components.Length - 1).GetFullPathName
                                                (), file1.ToString());
            // record the modification time of the inode
            long modTime = nodesInPath.GetINode(nodesInPath.Length() - 1).GetModificationTime
                               ();

            // Create a snapshot for the dir, and check the inodes for the path
            // pointing to a snapshot file
            hdfs.AllowSnapshot(sub1);
            hdfs.CreateSnapshot(sub1, "s3");
            // Modify file1
            DFSTestUtil.AppendFile(hdfs, file1, "the content for appending");
            // Check the INodes for snapshot of file1
            string snapshotPath = sub1.ToString() + "/.snapshot/s3/file1";

            names      = INode.GetPathNames(snapshotPath);
            components = INode.GetPathComponents(names);
            INodesInPath ssNodesInPath = INodesInPath.Resolve(fsdir.rootDir, components, false
                                                              );

            // Length of ssInodes should be (components.length - 1), since we will
            // ignore ".snapshot"
            NUnit.Framework.Assert.AreEqual(ssNodesInPath.Length(), components.Length - 1);
            Org.Apache.Hadoop.Hdfs.Server.Namenode.Snapshot.Snapshot s3 = GetSnapshot(ssNodesInPath
                                                                                      , "s3", 3);
            AssertSnapshot(ssNodesInPath, true, s3, 3);
            // Check the INode for snapshot of file1
            INode snapshotFileNode = ssNodesInPath.GetLastINode();

            NUnit.Framework.Assert.AreEqual(snapshotFileNode.GetLocalName(), file1.GetName());
            NUnit.Framework.Assert.IsTrue(snapshotFileNode.AsFile().IsWithSnapshot());
            // The modification time of the snapshot INode should be the same with the
            // original INode before modification
            NUnit.Framework.Assert.AreEqual(modTime, snapshotFileNode.GetModificationTime(ssNodesInPath
                                                                                          .GetPathSnapshotId()));
            // Check the INode for /TestSnapshot/sub1/file1 again
            names      = INode.GetPathNames(file1.ToString());
            components = INode.GetPathComponents(names);
            INodesInPath newNodesInPath = INodesInPath.Resolve(fsdir.rootDir, components, false
                                                               );

            AssertSnapshot(newNodesInPath, false, s3, -1);
            // The number of inodes should be equal to components.length
            NUnit.Framework.Assert.AreEqual(newNodesInPath.Length(), components.Length);
            // The last INode should be associated with file1
            int last = components.Length - 1;

            NUnit.Framework.Assert.AreEqual(newNodesInPath.GetINode(last).GetFullPathName(),
                                            file1.ToString());
            // The modification time of the INode for file3 should have been changed
            NUnit.Framework.Assert.IsFalse(modTime == newNodesInPath.GetINode(last).GetModificationTime
                                               ());
            hdfs.DeleteSnapshot(sub1, "s3");
            hdfs.DisallowSnapshot(sub1);
        }
        /// <summary>for snapshot file.</summary>
        /// <exception cref="System.Exception"/>
        public virtual void TestSnapshotPathINodes()
        {
            // Create a snapshot for the dir, and check the inodes for the path
            // pointing to a snapshot file
            hdfs.AllowSnapshot(sub1);
            hdfs.CreateSnapshot(sub1, "s1");
            // The path when accessing the snapshot file of file1 is
            // /TestSnapshot/sub1/.snapshot/s1/file1
            string snapshotPath = sub1.ToString() + "/.snapshot/s1/file1";

            string[]     names       = INode.GetPathNames(snapshotPath);
            byte[][]     components  = INode.GetPathComponents(names);
            INodesInPath nodesInPath = INodesInPath.Resolve(fsdir.rootDir, components, false);

            // Length of inodes should be (components.length - 1), since we will ignore
            // ".snapshot"
            NUnit.Framework.Assert.AreEqual(nodesInPath.Length(), components.Length - 1);
            // SnapshotRootIndex should be 3: {root, Testsnapshot, sub1, s1, file1}
            Org.Apache.Hadoop.Hdfs.Server.Namenode.Snapshot.Snapshot snapshot = GetSnapshot(nodesInPath
                                                                                            , "s1", 3);
            AssertSnapshot(nodesInPath, true, snapshot, 3);
            // Check the INode for file1 (snapshot file)
            INode snapshotFileNode = nodesInPath.GetLastINode();

            AssertINodeFile(snapshotFileNode, file1);
            NUnit.Framework.Assert.IsTrue(snapshotFileNode.GetParent().IsWithSnapshot());
            // Call getExistingPathINodes and request only one INode.
            nodesInPath = INodesInPath.Resolve(fsdir.rootDir, components, false);
            NUnit.Framework.Assert.AreEqual(nodesInPath.Length(), components.Length - 1);
            AssertSnapshot(nodesInPath, true, snapshot, 3);
            // Check the INode for file1 (snapshot file)
            AssertINodeFile(nodesInPath.GetLastINode(), file1);
            // Resolve the path "/TestSnapshot/sub1/.snapshot"
            string dotSnapshotPath = sub1.ToString() + "/.snapshot";

            names       = INode.GetPathNames(dotSnapshotPath);
            components  = INode.GetPathComponents(names);
            nodesInPath = INodesInPath.Resolve(fsdir.rootDir, components, false);
            // The number of INodes returned should still be components.length
            // since we put a null in the inode array for ".snapshot"
            NUnit.Framework.Assert.AreEqual(nodesInPath.Length(), components.Length);
            // No SnapshotRoot dir is included in the resolved inodes
            AssertSnapshot(nodesInPath, true, snapshot, -1);
            // The last INode should be null, the last but 1 should be sub1
            NUnit.Framework.Assert.IsNull(nodesInPath.GetLastINode());
            NUnit.Framework.Assert.AreEqual(nodesInPath.GetINode(-2).GetFullPathName(), sub1.
                                            ToString());
            NUnit.Framework.Assert.IsTrue(nodesInPath.GetINode(-2).IsDirectory());
            string[] invalidPathComponent = new string[] { "invalidDir", "foo", ".snapshot",
                                                           "bar" };
            Path invalidPath = new Path(invalidPathComponent[0]);

            for (int i = 1; i < invalidPathComponent.Length; i++)
            {
                invalidPath = new Path(invalidPath, invalidPathComponent[i]);
                try
                {
                    hdfs.GetFileStatus(invalidPath);
                    NUnit.Framework.Assert.Fail();
                }
                catch (FileNotFoundException fnfe)
                {
                    System.Console.Out.WriteLine("The exception is expected: " + fnfe);
                }
            }
            hdfs.DeleteSnapshot(sub1, "s1");
            hdfs.DisallowSnapshot(sub1);
        }