def test_gen_l3():
str = 'hat'
p = permutation_string.perm_rec(str)
assert len(p) == 6
assert p == ['hat', 'aht', 'ath', 'hta', 'tha', 'tah']
p = permutation_string.perm_rec('aaa')
assert len(p) == 6
assert p == ['aaa', 'aaa', 'aaa', 'aaa', 'aaa', 'aaa']
def test_gen_l5():
str = 'haste'
p = permutation_string.perm_rec(str)
assert len(p) == 120
def test_gen_l4():
str = 'hats'
p = permutation_string.perm_rec(str)
assert len(p) == 24
def test_gen_l1():
str = 'o'
p = permutation_string.perm_rec(str)
assert len(p) == 1
assert p == ['o']
def test_gen_l2():
str = 'ox'
p = permutation_string.perm_rec(str)
assert len(p) == 2
assert p == ['ox', 'xo']