SimpleFileVisitor implements FileVisitor<T> { @Override public FileVisitResult preVisitDirectory(T dir, BasicFileAttributes attrs) throws IOException { checkNotNull("dir", dir); checkNotNull("attrs", attrs); return FileVisitResult.CONTINUE; } protected  SimpleFileVisitor(); @Override FileVisitResult preVisitDirectory(T dir,
                                             BasicFileAttributes attrs); @Override FileVisitResult visitFile(T file,
                                     BasicFileAttributes attrs); @Override FileVisitResult visitFileFailed(T file,
                                           IOException exc); @Override FileVisitResult postVisitDirectory(T dir,
                                              IOException exc);  }
@Test(expected = IllegalArgumentException.class) public void preVisitDirectoryNull1() { final Path dir = newTempDir(null); final Path file = Files.createTempFile(dir, "foo", "bar"); simple.preVisitDirectory(null, Files.readAttributes(file, BasicFileAttributes.class)); }
@Test(expected = IllegalArgumentException.class) public void preVisitDirectoryNull2() { final Path dir = newTempDir(null); simple.preVisitDirectory(dir, null); }
@Test(expected = IllegalArgumentException.class) public void preVisitDirectoryNull3() { simple.preVisitDirectory(null, null); }