def test_surface():
    import numpy as np

    from ase import Atoms, Atom
    from ase.build import fcc111, fcc211, add_adsorbate, bulk, surface
    import math

    atoms = fcc211('Au', (3, 5, 8), vacuum=10.)
    assert len(atoms) == 120

    atoms = atoms.repeat((2, 1, 1))
    assert np.allclose(atoms.get_distance(0, 130), 2.88499566724)

    atoms = fcc111('Ni', (2, 2, 4), orthogonal=True)
    add_adsorbate(atoms, 'H', 1, 'bridge')
    add_adsorbate(atoms, Atom('O'), 1, 'fcc')
    add_adsorbate(atoms, Atoms('F'), 1, 'hcp')

    # The next test ensures that a simple string of multiple atoms cannot be used,
    # which should fail with a KeyError that reports the name of the molecule due
    # to the string failing to work with Atom().
    failed = False
    try:
        add_adsorbate(atoms, 'CN', 1, 'ontop')
    except KeyError as e:
        failed = True
        assert e.args[0] == 'CN'
    assert failed

    # This test ensures that the default periodic behavior remains unchanged
    cubic_fcc = bulk("Al", a=4.05, cubic=True)
    surface_fcc = surface(cubic_fcc, (1, 1, 1), 3)

    assert list(surface_fcc.pbc) == [True, True, False]
    assert surface_fcc.cell[2][2] == 0

    # This test checks the new periodic option
    cubic_fcc = bulk("Al", a=4.05, cubic=True)
    surface_fcc = surface(cubic_fcc, (1, 1, 1), 3, periodic=True)

    assert (list(surface_fcc.pbc) == [True, True, True])
    expected_length = 4.05*3**0.5  # for FCC with a=4.05
    assert math.isclose(surface_fcc.cell[2][2], expected_length)
