def test_system():
system = System(box_size=[5, 5, 5])
# No molecules yet in the system
assert len(system) == 0
system += h2o
assert len(system) == 1
system.add_molecules(h2o, 10)
assert len(system) == 11
two_waters = [h2o, h2o]
system += two_waters
assert len(system) == 13
assert system.n_unique_molecules == 1
assert str(system) == 'H2O_13' or str(system) == 'OH2_13'
# Should be able to print an xyz file of the configuration
system.configuration().save(filename='test.xyz')
assert os.path.exists('test.xyz')
os.remove('test.xyz')
def test_dftb_plus():
water_box = System(box_size=[5, 5, 5])
config = water_box.configuration()
config.set_atoms(xyz_filename=os.path.join(here, 'data', 'h2o_10.xyz'))
if 'GT_DFTB' not in os.environ or not os.environ['GT_DFTB'] == 'True':
return
config.run_dftb()
assert config.energy is not None
forces = config.forces
assert type(forces) is np.ndarray
assert forces.shape == (30, 3)
# Should all be non-zero length force vectors in ev Å^-1
assert all(0 < np.linalg.norm(force) < 70 for force in forces)