Path path = FS.getPath("nonexistent.file");
    assertNull(path.getParent());
    assertNotNull(path.toAbsolutePath().getParent());
    MoreFiles.createParentDirectories(path); // test that there's no exception
  }

  public void testCreateParentDirectories_noParentsNeeded() throws IOException {
    Path path = tempDir.resolve("nonexistent.file");
    assertTrue(Files.exists(path.getParent()));

    File file = file("nonexistent.file");
    assertNull(file.getParentFile());
    assertNotNull(file.getCanonicalFile().getParentFile());
    Files.createParentDirs(file);
  }

  public void testCreateParentDirs_noParentsNeeded() throws IOException {
    File file = file(getTempDir(), "nonexistent.file");
    assertTrue(file.getParentFile().exists());

    File file = file("nonexistent.file");
    assertNull(file.getParentFile());
    assertNotNull(file.getCanonicalFile().getParentFile());
    Files.createParentDirs(file);
  }

  public void testCreateParentDirs_noParentsNeeded() throws IOException {
    File file = file(getTempDir(), "nonexistent.file");
    assertTrue(file.getParentFile().exists());

    }
  }

  /**
   * Creates any necessary but nonexistent parent directories of the specified file. Note that if
   * this operation fails it may have succeeded in creating some (but not all) of the necessary
   * parent directories.
   *
   * @throws IOException if an I/O error occurs, or if any necessary but nonexistent parent
   *     directories of the specified file could not be created.
   * @since 4.0