def test_exchange_mif():
A = 1e-11
exchange = Exchange(A)
mif_string = exchange.get_mif()
lines = mif_string.split('\n')
assert 'Specify Oxs_UniformExchange {' in lines[0]
assert 'A' in lines[1]
assert float(lines[1].split()[1]) == A
assert '}' in lines[2]
def test_exchange_formatting():
A = 1e-11
exchange = Exchange(A)
mif_string = exchange.get_mif()
assert mif_string[0] == 'S'