'Verify that a valid subdirectory will show up as a directory, but not as a
file, not as a symlink, and be listable.'

def test_validSubdir(self):

    sub1 = self.path.child('sub1')
    self.assertTrue(sub1.exists(), 'This    directory    does    exist.')
    self.assertTrue(sub1.isdir(), "It's    a    directory.")
    self.assertFalse(sub1.isfile(), "It's    a    directory.")
    self.assertFalse(sub1.islink(), "It's    a    directory.")
    self.assertEqual(sub1.listdir(), ['file2'])
