from ase.build import molecule
from ase.calculators.onetep import Onetep
from os.path import isfile, dirname, abspath, join

mol = molecule('H2O')
mol.center(8)
calc = Onetep(label='water')
# Tests conducted with the JTH PAW data set.
# http://www.abinit.org/downloads/PAW2
prefix = dirname(abspath(__file__))
h_path = join(prefix, 'H.abinit')
o_path = join(prefix, 'O.abinit')
if not (isfile(h_path) and isfile(o_path)):
    raise Exception("""You must supply PAW data sets for
        hydrogen and oxygen to run this test.
        Please see http://www.abinit.org/downloads/PAW2
        for suitable data. ONETEP takes PAW data sets in the
        abinit format. I need H.abinit and O.abinit""")
calc.set_pseudos([('H', h_path), ('O', o_path)])
calc.set(paw=True, xc='PBE')
mol.set_calculator(calc)

energy = mol.get_total_energy()
ref_energy = -471.576999443
assert abs(energy - ref_energy) < 1e-8