public void unlink(Name name) {
    DirectoryEntry entry = remove(checkNotReserved(name, "unlink"));
    entry.file().unlinked();
  }
@Test
  public void testUnlink_nonExistentNameFails() {
    try {
      dir.unlink(Name.simple("bar"));
      fail();
    } catch (IllegalArgumentException expected) {
    }
  }