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Posted to common-commits@hadoop.apache.org by cm...@apache.org on 2013/07/12 00:36:37 UTC

svn commit: r1502387 - /hadoop/common/branches/branch-2.1-beta/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/SymlinkBaseTest.java

Author: cmccabe
Date: Thu Jul 11 22:36:37 2013
New Revision: 1502387

URL: http://svn.apache.org/r1502387
Log:
HADOOP-9418.  Add symlink support to DistributedFileSystem (Andrew Wang via Colin Patrick McCabe)

Added:
    hadoop/common/branches/branch-2.1-beta/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/SymlinkBaseTest.java

Added: hadoop/common/branches/branch-2.1-beta/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/SymlinkBaseTest.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/branch-2.1-beta/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/SymlinkBaseTest.java?rev=1502387&view=auto
==============================================================================
--- hadoop/common/branches/branch-2.1-beta/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/SymlinkBaseTest.java (added)
+++ hadoop/common/branches/branch-2.1-beta/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/SymlinkBaseTest.java Thu Jul 11 22:36:37 2013
@@ -0,0 +1,1373 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.fs;
+
+import java.io.*;
+import java.net.URI;
+import java.util.EnumSet;
+import org.apache.hadoop.fs.FileContext;
+import org.apache.hadoop.fs.Options.CreateOpts;
+import org.apache.hadoop.fs.Options.Rename;
+import org.apache.hadoop.fs.permission.FsPermission;
+import org.apache.hadoop.fs.CreateFlag;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.fs.FSDataOutputStream;
+import org.apache.hadoop.test.GenericTestUtils;
+
+import static org.junit.Assert.*;
+import static org.junit.Assume.assumeTrue;
+import org.junit.Test;
+import org.junit.Before;
+import org.junit.After;
+
+/**
+ * Base test for symbolic links
+ */
+public abstract class SymlinkBaseTest {
+  static final long seed = 0xDEADBEEFL;
+  static final int  blockSize =  8192;
+  static final int  fileSize  = 16384;
+  static final int numBlocks = fileSize / blockSize;
+
+  protected static FSTestWrapper wrapper;
+
+  abstract protected String getScheme();
+  abstract protected String testBaseDir1() throws IOException;
+  abstract protected String testBaseDir2() throws IOException;
+  abstract protected URI testURI();
+
+  protected IOException unwrapException(IOException e) {
+    return e;
+  }
+
+  protected static void createAndWriteFile(Path p) throws IOException {
+    createAndWriteFile(wrapper, p);
+  }
+
+  protected static void createAndWriteFile(FSTestWrapper wrapper, Path p)
+      throws IOException {
+    wrapper.createFile(p, numBlocks, CreateOpts.createParent(),
+        CreateOpts.repFac((short) 1), CreateOpts.blockSize(blockSize));
+  }
+
+  protected static void readFile(Path p) throws IOException {
+    wrapper.readFile(p, fileSize);
+  }
+
+  protected static void appendToFile(Path p) throws IOException {
+    wrapper.appendToFile(p, numBlocks,
+        CreateOpts.blockSize(blockSize));
+  }
+
+  @Before
+  public void setUp() throws Exception {
+    wrapper.mkdir(new Path(testBaseDir1()), FileContext.DEFAULT_PERM, true);
+    wrapper.mkdir(new Path(testBaseDir2()), FileContext.DEFAULT_PERM, true);
+  }
+
+  @After
+  public void tearDown() throws Exception {
+    wrapper.delete(new Path(testBaseDir1()), true);
+    wrapper.delete(new Path(testBaseDir2()), true);
+  }
+
+  @Test(timeout=10000)
+  /** The root is not a symlink */
+  public void testStatRoot() throws IOException {
+    assertFalse(wrapper.getFileLinkStatus(new Path("/")).isSymlink());
+  }
+
+  @Test(timeout=10000)
+  /** Test setWorkingDirectory not resolves symlinks */
+  public void testSetWDNotResolvesLinks() throws IOException {
+    Path dir       = new Path(testBaseDir1());
+    Path linkToDir = new Path(testBaseDir1()+"/link");
+    wrapper.createSymlink(dir, linkToDir, false);
+    wrapper.setWorkingDirectory(linkToDir);
+    assertEquals(linkToDir.getName(), wrapper.getWorkingDirectory().getName());
+  }
+
+  @Test(timeout=10000)
+  /** Test create a dangling link */
+  public void testCreateDanglingLink() throws IOException {
+    Path file = new Path("/noSuchFile");
+    Path link = new Path(testBaseDir1()+"/link");
+    wrapper.createSymlink(file, link, false);
+    try {
+      wrapper.getFileStatus(link);
+      fail("Got file status of non-existant file");
+    } catch (FileNotFoundException f) {
+      // Expected
+    }
+    wrapper.delete(link, false);
+  }
+
+  @Test(timeout=10000)
+  /** Test create a link to null and empty path */
+  public void testCreateLinkToNullEmpty() throws IOException {
+    Path link = new Path(testBaseDir1()+"/link");
+    try {
+      wrapper.createSymlink(null, link, false);
+      fail("Can't create symlink to null");
+    } catch (java.lang.NullPointerException e) {
+      // Expected, create* with null yields NPEs
+    }
+    try {
+      wrapper.createSymlink(new Path(""), link, false);
+      fail("Can't create symlink to empty string");
+    } catch (java.lang.IllegalArgumentException e) {
+      // Expected, Path("") is invalid
+    }
+  }
+
+  @Test(timeout=10000)
+  /** Create a link with createParent set */
+  public void testCreateLinkCanCreateParent() throws IOException {
+    Path file = new Path(testBaseDir1()+"/file");
+    Path link = new Path(testBaseDir2()+"/linkToFile");
+    createAndWriteFile(file);
+    wrapper.delete(new Path(testBaseDir2()), true);
+    try {
+      wrapper.createSymlink(file, link, false);
+      fail("Created link without first creating parent dir");
+    } catch (IOException x) {
+      // Expected. Need to create testBaseDir2() first.
+    }
+    assertFalse(wrapper.exists(new Path(testBaseDir2())));
+    wrapper.createSymlink(file, link, true);
+    readFile(link);
+  }
+
+  @Test(timeout=10000)
+  /** Try to create a directory given a path that refers to a symlink */
+  public void testMkdirExistingLink() throws IOException {
+    Path dir  = new Path(testBaseDir1()+"/link");
+    wrapper.createSymlink(new Path("/doesNotExist"), dir, false);
+    try {
+      wrapper.mkdir(dir, FileContext.DEFAULT_PERM, false);
+      fail("Created a dir where a symlink exists");
+    } catch (FileAlreadyExistsException e) {
+      // Expected. The symlink already exists.
+    } catch (IOException e) {
+      // LocalFs just throws an IOException
+      assertEquals("file", getScheme());
+    }
+  }
+
+  @Test(timeout=10000)
+  /** Try to create a file with parent that is a dangling link */
+  public void testCreateFileViaDanglingLinkParent() throws IOException {
+    Path dir  = new Path(testBaseDir1()+"/dangling");
+    Path file = new Path(testBaseDir1()+"/dangling/file");
+    wrapper.createSymlink(new Path("/doesNotExist"), dir, false);
+    FSDataOutputStream out;
+    try {
+      out = wrapper.create(file, EnumSet.of(CreateFlag.CREATE),
+                      CreateOpts.repFac((short) 1),
+                      CreateOpts.blockSize(blockSize));
+      out.close();
+      fail("Created a link with dangling link parent");
+    } catch (FileNotFoundException e) {
+      // Expected. The parent is dangling.
+    }
+  }
+
+  @Test(timeout=10000)
+  /** Delete a link */
+  public void testDeleteLink() throws IOException {
+    Path file = new Path(testBaseDir1()+"/file");
+    Path link = new Path(testBaseDir1()+"/linkToFile");
+    createAndWriteFile(file);
+    wrapper.createSymlink(file, link, false);
+    readFile(link);
+    wrapper.delete(link, false);
+    try {
+      readFile(link);
+      fail("Symlink should have been deleted");
+    } catch (IOException x) {
+      // Expected
+    }
+    // If we deleted the link we can put it back
+    wrapper.createSymlink(file, link, false);
+  }
+
+  @Test(timeout=10000)
+  /** Ensure open resolves symlinks */
+  public void testOpenResolvesLinks() throws IOException {
+    Path file = new Path(testBaseDir1()+"/noSuchFile");
+    Path link = new Path(testBaseDir1()+"/link");
+    wrapper.createSymlink(file, link, false);
+    try {
+      wrapper.open(link);
+      fail("link target does not exist");
+    } catch (FileNotFoundException x) {
+      // Expected
+    }
+    wrapper.delete(link, false);
+  }
+
+  @Test(timeout=10000)
+  /** Stat a link to a file */
+  public void testStatLinkToFile() throws IOException {
+    Path file = new Path(testBaseDir1()+"/file");
+    Path linkToFile = new Path(testBaseDir1()+"/linkToFile");
+    createAndWriteFile(file);
+    wrapper.createSymlink(file, linkToFile, false);
+    assertFalse(wrapper.getFileLinkStatus(linkToFile).isDirectory());
+    assertTrue(wrapper.isSymlink(linkToFile));
+    assertTrue(wrapper.isFile(linkToFile));
+    assertFalse(wrapper.isDir(linkToFile));
+    assertEquals(file.toUri().getPath(),
+                 wrapper.getLinkTarget(linkToFile).toString());
+    // The local file system does not fully resolve the link
+    // when obtaining the file status
+    if (!"file".equals(getScheme())) {
+      assertEquals(wrapper.getFileStatus(file),
+                   wrapper.getFileStatus(linkToFile));
+      assertEquals(wrapper.makeQualified(file),
+                   wrapper.getFileStatus(linkToFile).getPath());
+      assertEquals(wrapper.makeQualified(linkToFile),
+                   wrapper.getFileLinkStatus(linkToFile).getPath());
+    }
+  }
+
+  @Test(timeout=10000)
+  /** Stat a relative link to a file */
+  public void testStatRelLinkToFile() throws IOException {
+    assumeTrue(!"file".equals(getScheme()));
+    Path file       = new Path(testBaseDir1(), "file");
+    Path linkToFile = new Path(testBaseDir1(), "linkToFile");
+    createAndWriteFile(file);
+    wrapper.createSymlink(new Path("file"), linkToFile, false);
+    assertEquals(wrapper.getFileStatus(file),
+                 wrapper.getFileStatus(linkToFile));
+    assertEquals(wrapper.makeQualified(file),
+                 wrapper.getFileStatus(linkToFile).getPath());
+    assertEquals(wrapper.makeQualified(linkToFile),
+                 wrapper.getFileLinkStatus(linkToFile).getPath());
+  }
+
+  @Test(timeout=10000)
+  /** Stat a link to a directory */
+  public void testStatLinkToDir() throws IOException {
+    Path dir  = new Path(testBaseDir1());
+    Path linkToDir = new Path(testBaseDir1()+"/linkToDir");
+    wrapper.createSymlink(dir, linkToDir, false);
+
+    assertFalse(wrapper.getFileStatus(linkToDir).isSymlink());
+    assertTrue(wrapper.isDir(linkToDir));
+    assertFalse(wrapper.getFileLinkStatus(linkToDir).isDirectory());
+    assertTrue(wrapper.getFileLinkStatus(linkToDir).isSymlink());
+
+    assertFalse(wrapper.isFile(linkToDir));
+    assertTrue(wrapper.isDir(linkToDir));
+
+    assertEquals(dir.toUri().getPath(),
+                 wrapper.getLinkTarget(linkToDir).toString());
+  }
+
+  @Test(timeout=10000)
+  /** Stat a dangling link */
+  public void testStatDanglingLink() throws IOException {
+    Path file = new Path("/noSuchFile");
+    Path link = new Path(testBaseDir1()+"/link");
+    wrapper.createSymlink(file, link, false);
+    assertFalse(wrapper.getFileLinkStatus(link).isDirectory());
+    assertTrue(wrapper.getFileLinkStatus(link).isSymlink());
+  }
+
+  @Test(timeout=10000)
+  /** Stat a non-existant file */
+  public void testStatNonExistentFiles() throws IOException {
+    Path fileAbs = new Path("/doesNotExist");
+    try {
+      wrapper.getFileLinkStatus(fileAbs);
+      fail("Got FileStatus for non-existant file");
+    } catch (FileNotFoundException f) {
+      // Expected
+    }
+    try {
+      wrapper.getLinkTarget(fileAbs);
+      fail("Got link target for non-existant file");
+    } catch (FileNotFoundException f) {
+      // Expected
+    }
+  }
+
+  @Test(timeout=10000)
+  /** Test stat'ing a regular file and directory */
+  public void testStatNonLinks() throws IOException {
+    Path dir   = new Path(testBaseDir1());
+    Path file  = new Path(testBaseDir1()+"/file");
+    createAndWriteFile(file);
+    try {
+      wrapper.getLinkTarget(dir);
+      fail("Lstat'd a non-symlink");
+    } catch (IOException e) {
+      // Expected.
+    }
+    try {
+      wrapper.getLinkTarget(file);
+      fail("Lstat'd a non-symlink");
+    } catch (IOException e) {
+      // Expected.
+    }
+  }
+
+  @Test(timeout=10000)
+  /** Test links that link to each other */
+  public void testRecursiveLinks() throws IOException {
+    Path link1 = new Path(testBaseDir1()+"/link1");
+    Path link2 = new Path(testBaseDir1()+"/link2");
+    wrapper.createSymlink(link1, link2, false);
+    wrapper.createSymlink(link2, link1, false);
+    try {
+      readFile(link1);
+      fail("Read recursive link");
+    } catch (FileNotFoundException f) {
+      // LocalFs throws sub class of IOException, since File.exists
+      // returns false for a link to link.
+    } catch (IOException x) {
+      assertEquals("Possible cyclic loop while following symbolic link "+
+                   link1.toString(), x.getMessage());
+    }
+  }
+
+  /* Assert that the given link to a file behaves as expected. */
+  private void checkLink(Path linkAbs, Path expectedTarget, Path targetQual)
+      throws IOException {
+    Path dir = new Path(testBaseDir1());
+    // isFile/Directory
+    assertTrue(wrapper.isFile(linkAbs));
+    assertFalse(wrapper.isDir(linkAbs));
+
+    // Check getFileStatus
+    assertFalse(wrapper.getFileStatus(linkAbs).isSymlink());
+    assertFalse(wrapper.getFileStatus(linkAbs).isDirectory());
+    assertEquals(fileSize, wrapper.getFileStatus(linkAbs).getLen());
+
+    // Check getFileLinkStatus
+    assertTrue(wrapper.isSymlink(linkAbs));
+    assertFalse(wrapper.getFileLinkStatus(linkAbs).isDirectory());
+
+    // Check getSymlink always returns a qualified target, except
+    // when partially qualified paths are used (see tests below).
+    assertEquals(targetQual.toString(),
+        wrapper.getFileLinkStatus(linkAbs).getSymlink().toString());
+    assertEquals(targetQual, wrapper.getFileLinkStatus(linkAbs).getSymlink());
+    // Check that the target is qualified using the file system of the
+    // path used to access the link (if the link target was not specified
+    // fully qualified, in that case we use the link target verbatim).
+    if (!"file".equals(getScheme())) {
+      FileContext localFc = FileContext.getLocalFSFileContext();
+      Path linkQual = new Path(testURI().toString(), linkAbs);
+      assertEquals(targetQual,
+                   localFc.getFileLinkStatus(linkQual).getSymlink());
+    }
+
+    // Check getLinkTarget
+    assertEquals(expectedTarget, wrapper.getLinkTarget(linkAbs));
+
+    // Now read using all path types..
+    wrapper.setWorkingDirectory(dir);
+    readFile(new Path("linkToFile"));
+    readFile(linkAbs);
+    // And fully qualified.. (NB: for local fs this is partially qualified)
+    readFile(new Path(testURI().toString(), linkAbs));
+    // And partially qualified..
+    boolean failureExpected = true;
+    // local files are special cased, no authority
+    if ("file".equals(getScheme())) {
+      failureExpected = false;
+    }
+    // FileSystem automatically adds missing authority if scheme matches default
+    else if (wrapper instanceof FileSystemTestWrapper) {
+      failureExpected = false;
+    }
+    try {
+      readFile(new Path(getScheme()+"://"+testBaseDir1()+"/linkToFile"));
+      assertFalse(failureExpected);
+    } catch (Exception e) {
+      if (!failureExpected) {
+        throw new IOException(e);
+      }
+      //assertTrue(failureExpected);
+    }
+
+    // Now read using a different file context (for HDFS at least)
+    if (wrapper instanceof FileContextTestWrapper
+        && !"file".equals(getScheme())) {
+      FSTestWrapper localWrapper = wrapper.getLocalFSWrapper();
+      localWrapper.readFile(new Path(testURI().toString(), linkAbs), fileSize);
+    }
+  }
+
+  @Test(timeout=10000)
+  /** Test creating a symlink using relative paths */
+  public void testCreateLinkUsingRelPaths() throws IOException {
+    Path fileAbs = new Path(testBaseDir1(), "file");
+    Path linkAbs = new Path(testBaseDir1(), "linkToFile");
+    Path schemeAuth = new Path(testURI().toString());
+    Path fileQual = new Path(schemeAuth, testBaseDir1()+"/file");
+    createAndWriteFile(fileAbs);
+
+    wrapper.setWorkingDirectory(new Path(testBaseDir1()));
+    wrapper.createSymlink(new Path("file"), new Path("linkToFile"), false);
+    checkLink(linkAbs, new Path("file"), fileQual);
+
+    // Now rename the link's parent. Because the target was specified
+    // with a relative path the link should still resolve.
+    Path dir1        = new Path(testBaseDir1());
+    Path dir2        = new Path(testBaseDir2());
+    Path linkViaDir2 = new Path(testBaseDir2(), "linkToFile");
+    Path fileViaDir2 = new Path(schemeAuth, testBaseDir2()+"/file");
+    wrapper.rename(dir1, dir2, Rename.OVERWRITE);
+    FileStatus[] stats = wrapper.listStatus(dir2);
+    assertEquals(fileViaDir2,
+        wrapper.getFileLinkStatus(linkViaDir2).getSymlink());
+    readFile(linkViaDir2);
+  }
+
+  @Test(timeout=10000)
+  /** Test creating a symlink using absolute paths */
+  public void testCreateLinkUsingAbsPaths() throws IOException {
+    Path fileAbs = new Path(testBaseDir1()+"/file");
+    Path linkAbs = new Path(testBaseDir1()+"/linkToFile");
+    Path schemeAuth = new Path(testURI().toString());
+    Path fileQual = new Path(schemeAuth, testBaseDir1()+"/file");
+    createAndWriteFile(fileAbs);
+
+    wrapper.createSymlink(fileAbs, linkAbs, false);
+    checkLink(linkAbs, fileAbs, fileQual);
+
+    // Now rename the link's parent. The target doesn't change and
+    // now no longer exists so accessing the link should fail.
+    Path dir1        = new Path(testBaseDir1());
+    Path dir2        = new Path(testBaseDir2());
+    Path linkViaDir2 = new Path(testBaseDir2(), "linkToFile");
+    wrapper.rename(dir1, dir2, Rename.OVERWRITE);
+    assertEquals(fileQual, wrapper.getFileLinkStatus(linkViaDir2).getSymlink());
+    try {
+      readFile(linkViaDir2);
+      fail("The target should not exist");
+    } catch (FileNotFoundException x) {
+      // Expected
+    }
+  }
+
+  @Test(timeout=10000)
+  /**
+   * Test creating a symlink using fully and partially qualified paths.
+   * NB: For local fs this actually tests partially qualified paths,
+   * as they don't support fully qualified paths.
+   */
+  public void testCreateLinkUsingFullyQualPaths() throws IOException {
+    Path fileAbs  = new Path(testBaseDir1(), "file");
+    Path linkAbs  = new Path(testBaseDir1(), "linkToFile");
+    Path fileQual = new Path(testURI().toString(), fileAbs);
+    Path linkQual = new Path(testURI().toString(), linkAbs);
+    createAndWriteFile(fileAbs);
+
+    wrapper.createSymlink(fileQual, linkQual, false);
+    checkLink(linkAbs,
+              "file".equals(getScheme()) ? fileAbs : fileQual,
+              fileQual);
+
+    // Now rename the link's parent. The target doesn't change and
+    // now no longer exists so accessing the link should fail.
+    Path dir1        = new Path(testBaseDir1());
+    Path dir2        = new Path(testBaseDir2());
+    Path linkViaDir2 = new Path(testBaseDir2(), "linkToFile");
+    wrapper.rename(dir1, dir2, Rename.OVERWRITE);
+    assertEquals(fileQual, wrapper.getFileLinkStatus(linkViaDir2).getSymlink());
+    try {
+      readFile(linkViaDir2);
+      fail("The target should not exist");
+    } catch (FileNotFoundException x) {
+      // Expected
+    }
+  }
+
+  @Test(timeout=10000)
+  /**
+   * Test creating a symlink using partially qualified paths, ie a scheme
+   * but no authority and vice versa. We just test link targets here since
+   * creating using a partially qualified path is file system specific.
+   */
+  public void testCreateLinkUsingPartQualPath1() throws IOException {
+    // Partially qualified paths are covered for local file systems
+    // in the previous test.
+    assumeTrue(!"file".equals(getScheme()));
+    Path schemeAuth   = new Path(testURI().toString());
+    Path fileWoHost   = new Path(getScheme()+"://"+testBaseDir1()+"/file");
+    Path link         = new Path(testBaseDir1()+"/linkToFile");
+    Path linkQual     = new Path(schemeAuth, testBaseDir1()+"/linkToFile");
+    FSTestWrapper localWrapper = wrapper.getLocalFSWrapper();
+
+    wrapper.createSymlink(fileWoHost, link, false);
+    // Partially qualified path is stored
+    assertEquals(fileWoHost, wrapper.getLinkTarget(linkQual));
+    // NB: We do not add an authority
+    assertEquals(fileWoHost.toString(),
+      wrapper.getFileLinkStatus(link).getSymlink().toString());
+    assertEquals(fileWoHost.toString(),
+      wrapper.getFileLinkStatus(linkQual).getSymlink().toString());
+    // Ditto even from another file system
+    if (wrapper instanceof FileContextTestWrapper) {
+      assertEquals(fileWoHost.toString(),
+        localWrapper.getFileLinkStatus(linkQual).getSymlink().toString());
+    }
+    // Same as if we accessed a partially qualified path directly
+    try {
+      readFile(link);
+      fail("DFS requires URIs with schemes have an authority");
+    } catch (java.lang.RuntimeException e) {
+      assertTrue(wrapper instanceof FileContextTestWrapper);
+      // Expected
+    } catch (FileNotFoundException e) {
+      assertTrue(wrapper instanceof FileSystemTestWrapper);
+      GenericTestUtils.assertExceptionContains(
+          "File does not exist: /test1/file", e);
+    }
+  }
+
+  @Test(timeout=10000)
+  /** Same as above but vice versa (authority but no scheme) */
+  public void testCreateLinkUsingPartQualPath2() throws IOException {
+    Path link         = new Path(testBaseDir1(), "linkToFile");
+    Path fileWoScheme = new Path("//"+testURI().getAuthority()+
+                                 testBaseDir1()+"/file");
+    if ("file".equals(getScheme())) {
+      return;
+    }
+    wrapper.createSymlink(fileWoScheme, link, false);
+    assertEquals(fileWoScheme, wrapper.getLinkTarget(link));
+    assertEquals(fileWoScheme.toString(),
+      wrapper.getFileLinkStatus(link).getSymlink().toString());
+    try {
+      readFile(link);
+      fail("Accessed a file with w/o scheme");
+    } catch (IOException e) {
+      // Expected
+      if (wrapper instanceof FileContextTestWrapper) {
+        assertEquals("No AbstractFileSystem for scheme: null", e.getMessage());
+      } else if (wrapper instanceof FileSystemTestWrapper) {
+        assertEquals("No FileSystem for scheme: null", e.getMessage());
+      }
+    }
+  }
+
+  @Test(timeout=10000)
+  /** Lstat and readlink on a normal file and directory */
+  public void testLinkStatusAndTargetWithNonLink() throws IOException {
+    Path schemeAuth = new Path(testURI().toString());
+    Path dir        = new Path(testBaseDir1());
+    Path dirQual    = new Path(schemeAuth, dir.toString());
+    Path file       = new Path(testBaseDir1(), "file");
+    Path fileQual   = new Path(schemeAuth, file.toString());
+    createAndWriteFile(file);
+    assertEquals(wrapper.getFileStatus(file), wrapper.getFileLinkStatus(file));
+    assertEquals(wrapper.getFileStatus(dir), wrapper.getFileLinkStatus(dir));
+    try {
+      wrapper.getLinkTarget(file);
+      fail("Get link target on non-link should throw an IOException");
+    } catch (IOException x) {
+      assertEquals("Path "+fileQual+" is not a symbolic link", x.getMessage());
+    }
+    try {
+      wrapper.getLinkTarget(dir);
+      fail("Get link target on non-link should throw an IOException");
+    } catch (IOException x) {
+      assertEquals("Path "+dirQual+" is not a symbolic link", x.getMessage());
+    }
+  }
+
+  @Test(timeout=10000)
+  /** Test create symlink to a directory */
+  public void testCreateLinkToDirectory() throws IOException {
+    Path dir1      = new Path(testBaseDir1());
+    Path file      = new Path(testBaseDir1(), "file");
+    Path linkToDir = new Path(testBaseDir2(), "linkToDir");
+    createAndWriteFile(file);
+    wrapper.createSymlink(dir1, linkToDir, false);
+    assertFalse(wrapper.isFile(linkToDir));
+    assertTrue(wrapper.isDir(linkToDir));
+    assertTrue(wrapper.getFileStatus(linkToDir).isDirectory());
+    assertTrue(wrapper.getFileLinkStatus(linkToDir).isSymlink());
+  }
+
+  @Test(timeout=10000)
+  /** Test create and remove a file through a symlink */
+  public void testCreateFileViaSymlink() throws IOException {
+    Path dir         = new Path(testBaseDir1());
+    Path linkToDir   = new Path(testBaseDir2(), "linkToDir");
+    Path fileViaLink = new Path(linkToDir, "file");
+    wrapper.createSymlink(dir, linkToDir, false);
+    createAndWriteFile(fileViaLink);
+    assertTrue(wrapper.isFile(fileViaLink));
+    assertFalse(wrapper.isDir(fileViaLink));
+    assertFalse(wrapper.getFileLinkStatus(fileViaLink).isSymlink());
+    assertFalse(wrapper.getFileStatus(fileViaLink).isDirectory());
+    readFile(fileViaLink);
+    wrapper.delete(fileViaLink, true);
+    assertFalse(wrapper.exists(fileViaLink));
+  }
+
+  @Test(timeout=10000)
+  /** Test make and delete directory through a symlink */
+  public void testCreateDirViaSymlink() throws IOException {
+    Path dir1          = new Path(testBaseDir1());
+    Path subDir        = new Path(testBaseDir1(), "subDir");
+    Path linkToDir     = new Path(testBaseDir2(), "linkToDir");
+    Path subDirViaLink = new Path(linkToDir, "subDir");
+    wrapper.createSymlink(dir1, linkToDir, false);
+    wrapper.mkdir(subDirViaLink, FileContext.DEFAULT_PERM, true);
+    assertTrue(wrapper.isDir(subDirViaLink));
+    wrapper.delete(subDirViaLink, false);
+    assertFalse(wrapper.exists(subDirViaLink));
+    assertFalse(wrapper.exists(subDir));
+  }
+
+  @Test(timeout=10000)
+  /** Create symlink through a symlink */
+  public void testCreateLinkViaLink() throws IOException {
+    Path dir1        = new Path(testBaseDir1());
+    Path file        = new Path(testBaseDir1(), "file");
+    Path linkToDir   = new Path(testBaseDir2(), "linkToDir");
+    Path fileViaLink = new Path(linkToDir, "file");
+    Path linkToFile  = new Path(linkToDir, "linkToFile");
+    /*
+     * /b2/linkToDir            -> /b1
+     * /b2/linkToDir/linkToFile -> /b2/linkToDir/file
+     */
+    createAndWriteFile(file);
+    wrapper.createSymlink(dir1, linkToDir, false);
+    wrapper.createSymlink(fileViaLink, linkToFile, false);
+    assertTrue(wrapper.isFile(linkToFile));
+    assertTrue(wrapper.getFileLinkStatus(linkToFile).isSymlink());
+    readFile(linkToFile);
+    assertEquals(fileSize, wrapper.getFileStatus(linkToFile).getLen());
+    assertEquals(fileViaLink, wrapper.getLinkTarget(linkToFile));
+  }
+
+  @Test(timeout=10000)
+  /** Test create symlink to a directory */
+  public void testListStatusUsingLink() throws IOException {
+    Path file  = new Path(testBaseDir1(), "file");
+    Path link  = new Path(testBaseDir1(), "link");
+    createAndWriteFile(file);
+    wrapper.createSymlink(new Path(testBaseDir1()), link, false);
+    // The size of the result is file system dependent, Hdfs is 2 (file
+    // and link) and LocalFs is 3 (file, link, file crc).
+    FileStatus[] stats = wrapper.listStatus(link);
+    assertTrue(stats.length == 2 || stats.length == 3);
+    RemoteIterator<FileStatus> statsItor = wrapper.listStatusIterator(link);
+    int dirLen = 0;
+    while(statsItor.hasNext()) {
+      statsItor.next();
+      dirLen++;
+    }
+    assertTrue(dirLen == 2 || dirLen == 3);
+  }
+
+  @Test(timeout=10000)
+  /** Test create symlink using the same path */
+  public void testCreateLinkTwice() throws IOException {
+    Path file = new Path(testBaseDir1(), "file");
+    Path link = new Path(testBaseDir1(), "linkToFile");
+    createAndWriteFile(file);
+    wrapper.createSymlink(file, link, false);
+    try {
+      wrapper.createSymlink(file, link, false);
+      fail("link already exists");
+    } catch (IOException x) {
+      // Expected
+    }
+  }
+
+  @Test(timeout=10000)
+  /** Test access via a symlink to a symlink */
+  public void testCreateLinkToLink() throws IOException {
+    Path dir1        = new Path(testBaseDir1());
+    Path file        = new Path(testBaseDir1(), "file");
+    Path linkToDir   = new Path(testBaseDir2(), "linkToDir");
+    Path linkToLink  = new Path(testBaseDir2(), "linkToLink");
+    Path fileViaLink = new Path(testBaseDir2(), "linkToLink/file");
+    createAndWriteFile(file);
+    wrapper.createSymlink(dir1, linkToDir, false);
+    wrapper.createSymlink(linkToDir, linkToLink, false);
+    assertTrue(wrapper.isFile(fileViaLink));
+    assertFalse(wrapper.isDir(fileViaLink));
+    assertFalse(wrapper.getFileLinkStatus(fileViaLink).isSymlink());
+    assertFalse(wrapper.getFileStatus(fileViaLink).isDirectory());
+    readFile(fileViaLink);
+  }
+
+  @Test(timeout=10000)
+  /** Can not create a file with path that refers to a symlink */
+  public void testCreateFileDirExistingLink() throws IOException {
+    Path file = new Path(testBaseDir1(), "file");
+    Path link = new Path(testBaseDir1(), "linkToFile");
+    createAndWriteFile(file);
+    wrapper.createSymlink(file, link, false);
+    try {
+      createAndWriteFile(link);
+      fail("link already exists");
+    } catch (IOException x) {
+      // Expected
+    }
+    try {
+      wrapper.mkdir(link, FsPermission.getDefault(), false);
+      fail("link already exists");
+    } catch (IOException x) {
+      // Expected
+    }
+  }
+
+  @Test(timeout=10000)
+  /** Test deleting and recreating a symlink */
+  public void testUseLinkAferDeleteLink() throws IOException {
+    Path file = new Path(testBaseDir1(), "file");
+    Path link = new Path(testBaseDir1(), "linkToFile");
+    createAndWriteFile(file);
+    wrapper.createSymlink(file, link, false);
+    wrapper.delete(link, false);
+    try {
+      readFile(link);
+      fail("link was deleted");
+    } catch (IOException x) {
+      // Expected
+    }
+    readFile(file);
+    wrapper.createSymlink(file, link, false);
+    readFile(link);
+  }
+
+  @Test(timeout=10000)
+  /** Test create symlink to . */
+  public void testCreateLinkToDot() throws IOException {
+    Path dir  = new Path(testBaseDir1());
+    Path file = new Path(testBaseDir1(), "file");
+    Path link = new Path(testBaseDir1(), "linkToDot");
+    createAndWriteFile(file);
+    wrapper.setWorkingDirectory(dir);
+    try {
+      wrapper.createSymlink(new Path("."), link, false);
+      fail("Created symlink to dot");
+    } catch (IOException x) {
+      // Expected. Path(".") resolves to "" because URI normalizes
+      // the dot away and AbstractFileSystem considers "" invalid.
+    }
+  }
+
+  @Test(timeout=10000)
+  /** Test create symlink to .. */
+  public void testCreateLinkToDotDot() throws IOException {
+    Path file        = new Path(testBaseDir1(), "test/file");
+    Path dotDot      = new Path(testBaseDir1(), "test/..");
+    Path linkToDir   = new Path(testBaseDir2(), "linkToDir");
+    Path fileViaLink = new Path(linkToDir,      "test/file");
+    // Symlink to .. is not a problem since the .. is squashed early
+    assertEquals(testBaseDir1(), dotDot.toString());
+    createAndWriteFile(file);
+    wrapper.createSymlink(dotDot, linkToDir, false);
+    readFile(fileViaLink);
+    assertEquals(fileSize, wrapper.getFileStatus(fileViaLink).getLen());
+  }
+
+  @Test(timeout=10000)
+  /** Test create symlink to ../file */
+  public void testCreateLinkToDotDotPrefix() throws IOException {
+    Path file = new Path(testBaseDir1(), "file");
+    Path dir  = new Path(testBaseDir1(), "test");
+    Path link = new Path(testBaseDir1(), "test/link");
+    createAndWriteFile(file);
+    wrapper.mkdir(dir, FsPermission.getDefault(), false);
+    wrapper.setWorkingDirectory(dir);
+    wrapper.createSymlink(new Path("../file"), link, false);
+    readFile(link);
+    assertEquals(new Path("../file"), wrapper.getLinkTarget(link));
+  }
+
+  @Test(timeout=10000)
+  /** Test rename file using a path that contains a symlink. The rename should
+   * work as if the path did not contain a symlink */
+  public void testRenameFileViaSymlink() throws IOException {
+    Path dir            = new Path(testBaseDir1());
+    Path file           = new Path(testBaseDir1(), "file");
+    Path linkToDir      = new Path(testBaseDir2(), "linkToDir");
+    Path fileViaLink    = new Path(linkToDir, "file");
+    Path fileNewViaLink = new Path(linkToDir, "fileNew");
+    createAndWriteFile(file);
+    wrapper.createSymlink(dir, linkToDir, false);
+    wrapper.rename(fileViaLink, fileNewViaLink);
+    assertFalse(wrapper.exists(fileViaLink));
+    assertFalse(wrapper.exists(file));
+    assertTrue(wrapper.exists(fileNewViaLink));
+  }
+
+  @Test(timeout=10000)
+  /** Test rename a file through a symlink but this time only the
+   * destination path has an intermediate symlink. The rename should work
+   * as if the path did not contain a symlink */
+  public void testRenameFileToDestViaSymlink() throws IOException {
+    Path dir       = new Path(testBaseDir1());
+    Path file      = new Path(testBaseDir1(), "file");
+    Path linkToDir = new Path(testBaseDir2(), "linkToDir");
+    Path subDir    = new Path(linkToDir, "subDir");
+    createAndWriteFile(file);
+    wrapper.createSymlink(dir, linkToDir, false);
+    wrapper.mkdir(subDir, FileContext.DEFAULT_PERM, false);
+    try {
+      wrapper.rename(file, subDir);
+      fail("Renamed file to a directory");
+    } catch (IOException e) {
+      // Expected. Both must be directories.
+      assertTrue(unwrapException(e) instanceof IOException);
+    }
+    assertTrue(wrapper.exists(file));
+  }
+
+  @Test(timeout=10000)
+  /** Similar tests as the previous ones but rename a directory */
+  public void testRenameDirViaSymlink() throws IOException {
+    Path baseDir       = new Path(testBaseDir1());
+    Path dir           = new Path(baseDir, "dir");
+    Path linkToDir     = new Path(testBaseDir2(), "linkToDir");
+    Path dirViaLink    = new Path(linkToDir, "dir");
+    Path dirNewViaLink = new Path(linkToDir, "dirNew");
+    wrapper.mkdir(dir, FileContext.DEFAULT_PERM, false);
+    wrapper.createSymlink(baseDir, linkToDir, false);
+    assertTrue(wrapper.exists(dirViaLink));
+    wrapper.rename(dirViaLink, dirNewViaLink);
+    assertFalse(wrapper.exists(dirViaLink));
+    assertFalse(wrapper.exists(dir));
+    assertTrue(wrapper.exists(dirNewViaLink));
+  }
+
+  @Test(timeout=10000)
+  /** Similar tests as the previous ones but rename a symlink */
+  public void testRenameSymlinkViaSymlink() throws IOException {
+    Path baseDir        = new Path(testBaseDir1());
+    Path file           = new Path(testBaseDir1(), "file");
+    Path link           = new Path(testBaseDir1(), "link");
+    Path linkToDir      = new Path(testBaseDir2(), "linkToDir");
+    Path linkViaLink    = new Path(linkToDir, "link");
+    Path linkNewViaLink = new Path(linkToDir, "linkNew");
+    createAndWriteFile(file);
+    wrapper.createSymlink(file, link, false);
+    wrapper.createSymlink(baseDir, linkToDir, false);
+    wrapper.rename(linkViaLink, linkNewViaLink);
+    assertFalse(wrapper.exists(linkViaLink));
+    // Check that we didn't rename the link target
+    assertTrue(wrapper.exists(file));
+    assertTrue(wrapper.getFileLinkStatus(linkNewViaLink).isSymlink());
+    readFile(linkNewViaLink);
+  }
+
+  @Test(timeout=10000)
+  /** Test rename a directory to a symlink to a directory */
+  public void testRenameDirToSymlinkToDir() throws IOException {
+    Path dir1      = new Path(testBaseDir1());
+    Path subDir = new Path(testBaseDir2(), "subDir");
+    Path linkToDir = new Path(testBaseDir2(), "linkToDir");
+    wrapper.mkdir(subDir, FileContext.DEFAULT_PERM, false);
+    wrapper.createSymlink(subDir, linkToDir, false);
+    try {
+      wrapper.rename(dir1, linkToDir, Rename.OVERWRITE);
+      fail("Renamed directory to a symlink");
+    } catch (IOException e) {
+      // Expected. Both must be directories.
+      assertTrue(unwrapException(e) instanceof IOException);
+    }
+    assertTrue(wrapper.exists(dir1));
+    assertTrue(wrapper.exists(linkToDir));
+  }
+
+  @Test(timeout=10000)
+  /** Test rename a directory to a symlink to a file */
+  public void testRenameDirToSymlinkToFile() throws IOException {
+    Path dir1 = new Path(testBaseDir1());
+    Path file = new Path(testBaseDir2(), "file");
+    Path linkToFile = new Path(testBaseDir2(), "linkToFile");
+    createAndWriteFile(file);
+    wrapper.createSymlink(file, linkToFile, false);
+    try {
+      wrapper.rename(dir1, linkToFile, Rename.OVERWRITE);
+      fail("Renamed directory to a symlink");
+    } catch (IOException e) {
+      // Expected. Both must be directories.
+      assertTrue(unwrapException(e) instanceof IOException);
+    }
+    assertTrue(wrapper.exists(dir1));
+    assertTrue(wrapper.exists(linkToFile));
+  }
+
+  @Test(timeout=10000)
+  /** Test rename a directory to a dangling symlink */
+  public void testRenameDirToDanglingSymlink() throws IOException {
+    Path dir = new Path(testBaseDir1());
+    Path link = new Path(testBaseDir2(), "linkToFile");
+    wrapper.createSymlink(new Path("/doesNotExist"), link, false);
+    try {
+      wrapper.rename(dir, link, Rename.OVERWRITE);
+      fail("Renamed directory to a symlink");
+    } catch (IOException e) {
+      // Expected. Both must be directories.
+      assertTrue(unwrapException(e) instanceof IOException);
+    }
+    assertTrue(wrapper.exists(dir));
+    assertTrue(wrapper.getFileLinkStatus(link) != null);
+  }
+
+  @Test(timeout=10000)
+  /** Test rename a file to a symlink to a directory */
+  public void testRenameFileToSymlinkToDir() throws IOException {
+    Path file   = new Path(testBaseDir1(), "file");
+    Path subDir = new Path(testBaseDir1(), "subDir");
+    Path link   = new Path(testBaseDir1(), "link");
+    wrapper.mkdir(subDir, FileContext.DEFAULT_PERM, false);
+    wrapper.createSymlink(subDir, link, false);
+    createAndWriteFile(file);
+    try {
+      wrapper.rename(file, link);
+      fail("Renamed file to symlink w/o overwrite");
+    } catch (IOException e) {
+      // Expected
+      assertTrue(unwrapException(e) instanceof FileAlreadyExistsException);
+    }
+    wrapper.rename(file, link, Rename.OVERWRITE);
+    assertFalse(wrapper.exists(file));
+    assertTrue(wrapper.exists(link));
+    assertTrue(wrapper.isFile(link));
+    assertFalse(wrapper.getFileLinkStatus(link).isSymlink());
+  }
+
+  @Test(timeout=10000)
+  /** Test rename a file to a symlink to a file */
+  public void testRenameFileToSymlinkToFile() throws IOException {
+    Path file1 = new Path(testBaseDir1(), "file1");
+    Path file2 = new Path(testBaseDir1(), "file2");
+    Path link = new Path(testBaseDir1(), "linkToFile");
+    createAndWriteFile(file1);
+    createAndWriteFile(file2);
+    wrapper.createSymlink(file2, link, false);
+    try {
+      wrapper.rename(file1, link);
+      fail("Renamed file to symlink w/o overwrite");
+    } catch (IOException e) {
+      // Expected
+      assertTrue(unwrapException(e) instanceof FileAlreadyExistsException);
+    }
+    wrapper.rename(file1, link, Rename.OVERWRITE);
+    assertFalse(wrapper.exists(file1));
+    assertTrue(wrapper.exists(link));
+    assertTrue(wrapper.isFile(link));
+    assertFalse(wrapper.getFileLinkStatus(link).isSymlink());
+  }
+
+  @Test(timeout=10000)
+  /** Test rename a file to a dangling symlink */
+  public void testRenameFileToDanglingSymlink() throws IOException {
+    /* NB: Local file system doesn't handle dangling links correctly
+     * since File.exists(danglinLink) returns false. */
+    if ("file".equals(getScheme())) {
+      return;
+    }
+    Path file1 = new Path(testBaseDir1(), "file1");
+    Path link = new Path(testBaseDir1(), "linkToFile");
+    createAndWriteFile(file1);
+    wrapper.createSymlink(new Path("/doesNotExist"), link, false);
+    try {
+      wrapper.rename(file1, link);
+    } catch (IOException e) {
+      // Expected
+    }
+    wrapper.rename(file1, link, Rename.OVERWRITE);
+    assertFalse(wrapper.exists(file1));
+    assertTrue(wrapper.exists(link));
+    assertTrue(wrapper.isFile(link));
+    assertFalse(wrapper.getFileLinkStatus(link).isSymlink());
+  }
+
+  @Test(timeout=10000)
+  /** Rename a symlink to a new non-existant name */
+  public void testRenameSymlinkNonExistantDest() throws IOException {
+    Path file  = new Path(testBaseDir1(), "file");
+    Path link1 = new Path(testBaseDir1(), "linkToFile1");
+    Path link2 = new Path(testBaseDir1(), "linkToFile2");
+    createAndWriteFile(file);
+    wrapper.createSymlink(file, link1, false);
+    wrapper.rename(link1, link2);
+    assertTrue(wrapper.getFileLinkStatus(link2).isSymlink());
+    readFile(link2);
+    readFile(file);
+    assertFalse(wrapper.exists(link1));
+  }
+
+  @Test(timeout=10000)
+  /** Rename a symlink to a file that exists */
+  public void testRenameSymlinkToExistingFile() throws IOException {
+    Path file1 = new Path(testBaseDir1(), "file");
+    Path file2 = new Path(testBaseDir1(), "someFile");
+    Path link = new Path(testBaseDir1(), "linkToFile");
+    createAndWriteFile(file1);
+    createAndWriteFile(file2);
+    wrapper.createSymlink(file2, link, false);
+    try {
+      wrapper.rename(link, file1);
+      fail("Renamed w/o passing overwrite");
+    } catch (IOException e) {
+      // Expected
+      assertTrue(unwrapException(e) instanceof FileAlreadyExistsException);
+    }
+    wrapper.rename(link, file1, Rename.OVERWRITE);
+    assertFalse(wrapper.exists(link));
+    assertTrue(wrapper.getFileLinkStatus(file1).isSymlink());
+    assertEquals(file2, wrapper.getLinkTarget(file1));
+  }
+
+  @Test(timeout=10000)
+  /** Rename a symlink to a directory that exists */
+  public void testRenameSymlinkToExistingDir() throws IOException {
+    Path dir1   = new Path(testBaseDir1());
+    Path dir2   = new Path(testBaseDir2());
+    Path subDir = new Path(testBaseDir2(), "subDir");
+    Path link   = new Path(testBaseDir1(), "linkToDir");
+    wrapper.createSymlink(dir1, link, false);
+    try {
+      wrapper.rename(link, dir2);
+      fail("Renamed link to a directory");
+    } catch (IOException e) {
+      // Expected. Both must be directories.
+      assertTrue(unwrapException(e) instanceof IOException);
+    }
+    try {
+      wrapper.rename(link, dir2, Rename.OVERWRITE);
+      fail("Renamed link to a directory");
+    } catch (IOException e) {
+      // Expected. Both must be directories.
+      assertTrue(unwrapException(e) instanceof IOException);
+    }
+    // Also fails when dir2 has a sub-directory
+    wrapper.mkdir(subDir, FsPermission.getDefault(), false);
+    try {
+      wrapper.rename(link, dir2, Rename.OVERWRITE);
+      fail("Renamed link to a directory");
+    } catch (IOException e) {
+      // Expected. Both must be directories.
+      assertTrue(unwrapException(e) instanceof IOException);
+    }
+  }
+
+  @Test(timeout=10000)
+  /** Rename a symlink to itself */
+  public void testRenameSymlinkToItself() throws IOException {
+    Path link = new Path(testBaseDir1(), "linkToFile1");
+    wrapper.createSymlink(new Path("/doestNotExist"), link, false);
+    try {
+      wrapper.rename(link, link);
+    } catch (IOException e) {
+      assertTrue(unwrapException(e) instanceof FileAlreadyExistsException);
+    }
+    // Fails with overwrite as well
+    try {
+      wrapper.rename(link, link, Rename.OVERWRITE);
+    } catch (IOException e) {
+      assertTrue(unwrapException(e) instanceof FileAlreadyExistsException);
+    }
+  }
+
+  @Test(timeout=10000)
+  /** Rename a symlink */
+  public void testRenameSymlink() throws IOException {
+    Path file  = new Path(testBaseDir1(), "file");
+    Path link1 = new Path(testBaseDir1(), "linkToFile1");
+    Path link2 = new Path(testBaseDir1(), "linkToFile2");
+    createAndWriteFile(file);
+    wrapper.createSymlink(file, link1, false);
+    wrapper.rename(link1, link2);
+    assertTrue(wrapper.getFileLinkStatus(link2).isSymlink());
+    assertFalse(wrapper.getFileStatus(link2).isDirectory());
+    readFile(link2);
+    readFile(file);
+    try {
+      createAndWriteFile(link2);
+      fail("link was not renamed");
+    } catch (IOException x) {
+      // Expected
+    }
+  }
+
+  @Test(timeout=10000)
+  /** Rename a symlink to the file it links to */
+  public void testRenameSymlinkToFileItLinksTo() throws IOException {
+    /* NB: The rename is not atomic, so file is deleted before renaming
+     * linkToFile. In this interval linkToFile is dangling and local file
+     * system does not handle dangling links because File.exists returns
+     * false for dangling links. */
+    if ("file".equals(getScheme())) {
+      return;
+    }
+    Path file = new Path(testBaseDir1(), "file");
+    Path link = new Path(testBaseDir1(), "linkToFile");
+    createAndWriteFile(file);
+    wrapper.createSymlink(file, link, false);
+    try {
+      wrapper.rename(link, file);
+      fail("Renamed symlink to its target");
+    } catch (IOException e) {
+      assertTrue(unwrapException(e) instanceof FileAlreadyExistsException);
+    }
+    // Check the rename didn't happen
+    assertTrue(wrapper.isFile(file));
+    assertTrue(wrapper.exists(link));
+    assertTrue(wrapper.isSymlink(link));
+    assertEquals(file, wrapper.getLinkTarget(link));
+    try {
+      wrapper.rename(link, file, Rename.OVERWRITE);
+      fail("Renamed symlink to its target");
+    } catch (IOException e) {
+      assertTrue(unwrapException(e) instanceof FileAlreadyExistsException);
+    }
+    // Check the rename didn't happen
+    assertTrue(wrapper.isFile(file));
+    assertTrue(wrapper.exists(link));
+    assertTrue(wrapper.isSymlink(link));
+    assertEquals(file, wrapper.getLinkTarget(link));
+  }
+
+  @Test(timeout=10000)
+  /** Rename a symlink to the directory it links to */
+  public void testRenameSymlinkToDirItLinksTo() throws IOException {
+    /* NB: The rename is not atomic, so dir is deleted before renaming
+     * linkToFile. In this interval linkToFile is dangling and local file
+     * system does not handle dangling links because File.exists returns
+     * false for dangling links. */
+    if ("file".equals(getScheme())) {
+      return;
+    }
+    Path dir  = new Path(testBaseDir1(), "dir");
+    Path link = new Path(testBaseDir1(), "linkToDir");
+    wrapper.mkdir(dir, FileContext.DEFAULT_PERM, false);
+    wrapper.createSymlink(dir, link, false);
+    try {
+      wrapper.rename(link, dir);
+      fail("Renamed symlink to its target");
+    } catch (IOException e) {
+      assertTrue(unwrapException(e) instanceof FileAlreadyExistsException);
+    }
+    // Check the rename didn't happen
+    assertTrue(wrapper.isDir(dir));
+    assertTrue(wrapper.exists(link));
+    assertTrue(wrapper.isSymlink(link));
+    assertEquals(dir, wrapper.getLinkTarget(link));
+    try {
+      wrapper.rename(link, dir, Rename.OVERWRITE);
+      fail("Renamed symlink to its target");
+    } catch (IOException e) {
+      assertTrue(unwrapException(e) instanceof FileAlreadyExistsException);
+    }
+    // Check the rename didn't happen
+    assertTrue(wrapper.isDir(dir));
+    assertTrue(wrapper.exists(link));
+    assertTrue(wrapper.isSymlink(link));
+    assertEquals(dir, wrapper.getLinkTarget(link));
+  }
+
+  @Test(timeout=10000)
+  /** Test rename the symlink's target */
+  public void testRenameLinkTarget() throws IOException {
+    Path file    = new Path(testBaseDir1(), "file");
+    Path fileNew = new Path(testBaseDir1(), "fileNew");
+    Path link    = new Path(testBaseDir1(), "linkToFile");
+    createAndWriteFile(file);
+    wrapper.createSymlink(file, link, false);
+    wrapper.rename(file, fileNew, Rename.OVERWRITE);
+    try {
+      readFile(link);
+      fail("Link should be dangling");
+    } catch (IOException x) {
+      // Expected
+    }
+    wrapper.rename(fileNew, file, Rename.OVERWRITE);
+    readFile(link);
+  }
+
+  @Test(timeout=10000)
+  /** Test rename a file to path with destination that has symlink parent */
+  public void testRenameFileWithDestParentSymlink() throws IOException {
+    Path link  = new Path(testBaseDir1(), "link");
+    Path file1 = new Path(testBaseDir1(), "file1");
+    Path file2 = new Path(testBaseDir1(), "file2");
+    Path file3 = new Path(link, "file3");
+    Path dir2  = new Path(testBaseDir2());
+
+    // Renaming /dir1/file1 to non-existant file /dir1/link/file3 is OK
+    // if link points to a directory...
+    wrapper.createSymlink(dir2, link, false);
+    createAndWriteFile(file1);
+    wrapper.rename(file1, file3);
+    assertFalse(wrapper.exists(file1));
+    assertTrue(wrapper.exists(file3));
+    wrapper.rename(file3, file1);
+
+    // But fails if link is dangling...
+    wrapper.delete(link, false);
+    wrapper.createSymlink(file2, link, false);
+    try {
+      wrapper.rename(file1, file3);
+    } catch (IOException e) {
+      // Expected
+      assertTrue(unwrapException(e) instanceof FileNotFoundException);
+    }
+
+    // And if link points to a file...
+    createAndWriteFile(file2);
+    try {
+      wrapper.rename(file1, file3);
+    } catch (IOException e) {
+      // Expected
+      assertTrue(unwrapException(e) instanceof ParentNotDirectoryException);
+    }
+  }
+
+  @Test(timeout=10000)
+  /**
+   * Create, write, read, append, rename, get the block locations,
+   * checksums, and delete a file using a path with a symlink as an
+   * intermediate path component where the link target was specified
+   * using an absolute path. Rename is covered in more depth below.
+   */
+  public void testAccessFileViaInterSymlinkAbsTarget() throws IOException {
+    Path baseDir        = new Path(testBaseDir1());
+    Path file           = new Path(testBaseDir1(), "file");
+    Path fileNew        = new Path(baseDir, "fileNew");
+    Path linkToDir      = new Path(testBaseDir2(), "linkToDir");
+    Path fileViaLink    = new Path(linkToDir, "file");
+    Path fileNewViaLink = new Path(linkToDir, "fileNew");
+    wrapper.createSymlink(baseDir, linkToDir, false);
+    createAndWriteFile(fileViaLink);
+    assertTrue(wrapper.exists(fileViaLink));
+    assertTrue(wrapper.isFile(fileViaLink));
+    assertFalse(wrapper.isDir(fileViaLink));
+    assertFalse(wrapper.getFileLinkStatus(fileViaLink).isSymlink());
+    assertFalse(wrapper.isDir(fileViaLink));
+    assertEquals(wrapper.getFileStatus(file),
+                 wrapper.getFileLinkStatus(file));
+    assertEquals(wrapper.getFileStatus(fileViaLink),
+                 wrapper.getFileLinkStatus(fileViaLink));
+    readFile(fileViaLink);
+    appendToFile(fileViaLink);
+    wrapper.rename(fileViaLink, fileNewViaLink);
+    assertFalse(wrapper.exists(fileViaLink));
+    assertTrue(wrapper.exists(fileNewViaLink));
+    readFile(fileNewViaLink);
+    assertEquals(wrapper.getFileBlockLocations(fileNew, 0, 1).length,
+                 wrapper.getFileBlockLocations(fileNewViaLink, 0, 1).length);
+    assertEquals(wrapper.getFileChecksum(fileNew),
+                 wrapper.getFileChecksum(fileNewViaLink));
+    wrapper.delete(fileNewViaLink, true);
+    assertFalse(wrapper.exists(fileNewViaLink));
+  }
+
+  @Test(timeout=10000)
+  /**
+   * Operate on a file using a path with an intermediate symlink where
+   * the link target was specified as a fully qualified path.
+   */
+  public void testAccessFileViaInterSymlinkQualTarget() throws IOException {
+    Path baseDir        = new Path(testBaseDir1());
+    Path file           = new Path(testBaseDir1(), "file");
+    Path linkToDir      = new Path(testBaseDir2(), "linkToDir");
+    Path fileViaLink    = new Path(linkToDir, "file");
+    wrapper.createSymlink(wrapper.makeQualified(baseDir), linkToDir, false);
+    createAndWriteFile(fileViaLink);
+    assertEquals(wrapper.getFileStatus(file),
+                 wrapper.getFileLinkStatus(file));
+    assertEquals(wrapper.getFileStatus(fileViaLink),
+                 wrapper.getFileLinkStatus(fileViaLink));
+    readFile(fileViaLink);
+  }
+
+  @Test(timeout=10000)
+  /**
+   * Operate on a file using a path with an intermediate symlink where
+   * the link target was specified as a relative path.
+   */
+  public void testAccessFileViaInterSymlinkRelTarget() throws IOException {
+    assumeTrue(!"file".equals(getScheme()));
+    Path dir         = new Path(testBaseDir1(), "dir");
+    Path file        = new Path(dir, "file");
+    Path linkToDir   = new Path(testBaseDir1(), "linkToDir");
+    Path fileViaLink = new Path(linkToDir, "file");
+
+    wrapper.mkdir(dir, FileContext.DEFAULT_PERM, false);
+    wrapper.createSymlink(new Path("dir"), linkToDir, false);
+    createAndWriteFile(fileViaLink);
+    // Note that getFileStatus returns fully qualified paths even
+    // when called on an absolute path.
+    assertEquals(wrapper.makeQualified(file),
+                 wrapper.getFileStatus(file).getPath());
+    // In each case getFileLinkStatus returns the same FileStatus
+    // as getFileStatus since we're not calling it on a link and
+    // FileStatus objects are compared by Path.
+    assertEquals(wrapper.getFileStatus(file),
+                 wrapper.getFileLinkStatus(file));
+    assertEquals(wrapper.getFileStatus(fileViaLink),
+                 wrapper.getFileLinkStatus(fileViaLink));
+    assertEquals(wrapper.getFileStatus(fileViaLink),
+                 wrapper.getFileLinkStatus(file));
+  }
+
+  @Test(timeout=10000)
+  /** Test create, list, and delete a directory through a symlink */
+  public void testAccessDirViaSymlink() throws IOException {
+    Path baseDir    = new Path(testBaseDir1());
+    Path dir        = new Path(testBaseDir1(), "dir");
+    Path linkToDir  = new Path(testBaseDir2(), "linkToDir");
+    Path dirViaLink = new Path(linkToDir, "dir");
+    wrapper.createSymlink(baseDir, linkToDir, false);
+    wrapper.mkdir(dirViaLink, FileContext.DEFAULT_PERM, true);
+    assertTrue(wrapper.getFileStatus(dirViaLink).isDirectory());
+    FileStatus[] stats = wrapper.listStatus(dirViaLink);
+    assertEquals(0, stats.length);
+    RemoteIterator<FileStatus> statsItor = wrapper.listStatusIterator(dirViaLink);
+    assertFalse(statsItor.hasNext());
+    wrapper.delete(dirViaLink, false);
+    assertFalse(wrapper.exists(dirViaLink));
+    assertFalse(wrapper.exists(dir));
+  }
+
+  @Test(timeout=10000)
+  /** setTimes affects the target not the link */
+  public void testSetTimes() throws IOException {
+    Path file = new Path(testBaseDir1(), "file");
+    Path link = new Path(testBaseDir1(), "linkToFile");
+    createAndWriteFile(file);
+    wrapper.createSymlink(file, link, false);
+    long at = wrapper.getFileLinkStatus(link).getAccessTime();
+    wrapper.setTimes(link, 2L, 3L);
+    // NB: local file systems don't implement setTimes
+    if (!"file".equals(getScheme())) {
+      assertEquals(at, wrapper.getFileLinkStatus(link).getAccessTime());
+      assertEquals(3, wrapper.getFileStatus(file).getAccessTime());
+      assertEquals(2, wrapper.getFileStatus(file).getModificationTime());
+    }
+  }
+}