File grandparent = parent.getParentFile();
    assertFalse(grandparent.exists());
    Files.createParentDirs(file);
    assertTrue(parent.exists());
  }

  public void testCreateParentDirs_nonDirectoryParentExists() throws IOException {
    File parent = getTestFile("ascii.txt");
    assertTrue(parent.isFile());
    File file = file(parent, "foo");