def test_dir_fill(mock_copytree, mock_exists):
"""Tests filling one Dir with another."""
mock_exists.return_value = True
the_dir = Dir({'path' : '/test/dir/'})
fill_with = Dir({'path' : '/another/test/dir/'})
assert the_dir.fill(fill_with)
mock_copytree.assert_called_once_with('/another/test/dir/', '/test/dir/')
