def test_bounds_propagate_through_intersections():
x = rd.star(rd.char(b'\0\1'))
y = rd.star(rd.char(b'\1\2'))
assert isinstance(
rd.bounded(rd.intersection(x, y), 3),
rd.Intersection
)
def test_merges_multiple_subtracts():
x = rd.star(rd.char(b'012'))
y = rd.star(rd.char(b'0'))
z = rd.star(rd.char(b'1'))
t = rd.subtract(rd.subtract(x, y), z)
assert t is rd.subtract(x, rd.union(y, z))
t = rd.subtract(x, rd.subtract(y, z))
assert t.nullable
assert isinstance(t, rd.Union)
def test_bounds_propagate_through_subtraction():
x = rd.star(rd.char(b'\0\1'))
y = rd.literal(b'\0\0\0\1')
z = rd.subtract(x, y)
b = rd.bounded(z, 10)
assert isinstance(b, rd.Subtraction)
assert isinstance(b.left, rd.Bounded)
def test_bounds_are_not_nested():
x = rd.bounded(rd.star(rd.char(0)), 7)
y = rd.bounded(x, 5)
assert x.bound == 7
assert y.bound == 5
assert isinstance(y.child, rd.Star)
def test_derivatives_of_intersection():
x = rd.star(rd.char(b'\0\1'))
y = rd.star(rd.literal(b'\0\1'))
z = rd.intersection(x, y)
d1 = rd.derivative(z, 0)
d2 = rd.derivative(d1, 1)
assert d2 is z
def test_difference_of_same_is_none():
x = rd.char(0)
assert rd.witness_difference(x, x) is None
def test_valid_starts_of_subtraction():
x = rd.star(rd.char(b'\0\1'))
y = rd.char(b'\1')
z = rd.subtract(x, y)
assert rd.valid_starts(z) == pset([0, 1])
def test_removes_empty_from_unions():
c = rd.char(0)
assert c is rd.union(rd.Empty, c)
def test_two_phase_dfa():
re = rd.concatenate(rd.star(rd.char(0)), rd.star(rd.char(1)))
accepting, transitions = rd.build_dfa(re)
assert accepting == [True, True]
assert transitions == [{0: 0, 1: 1}, {1: 1}]
def test_complex_graphs_may_be_finite():
x = to_basic(rd.bounded(
rd.union(rd.star(rd.char(0)), rd.star(rd.char(1))), 20))
assert not rd.is_infinite(x)
def test_can_walk_graph_for_infintiy():
assert rd.is_infinite(rd.intersection(
rd.star(rd.char(b'01')), rd.star(rd.char(b'12'))
))
def test_basic_finite_are_not_infinite():
assert not rd.is_infinite(rd.Epsilon)
assert not rd.is_infinite(rd.char(0))
def test_empty_subtraction_is_identity():
x = rd.char(0)
assert rd.subtract(x, rd.Empty) is x
def test_self_subtraction_is_empty():
x = rd.char(0)
assert rd.subtract(x, x) is rd.Empty
def test_rebalances_concatenation():
x = rd.char(0)
y = rd.star(rd.char(1))
z = rd.char(2)
assert rd.concatenate(x, rd.concatenate(y, z)) is \
rd.concatenate(rd.concatenate(x, y), z)
def test_single_concatenation_is_self():
assert rd.concatenate(rd.char(0)) is rd.char(0)
def test_valid_starts_of_nullable_cat():
x = rd.concatenate(rd.star(rd.char(0)), rd.char(1))
assert rd.valid_starts(x) == pset([0, 1])
def test_self_intersection_is_identity():
x = rd.char(0)
assert rd.intersection(x, x, x) is x
def test_epsilon_prunes_down_intersections():
assert rd.intersection(rd.Epsilon, rd.star(rd.char(0))) is rd.Epsilon
assert rd.intersection(rd.Epsilon, rd.char(0)) is rd.Empty
def test_difference_of_epsilon_and_non_nullable_is_epsilon():
assert rd.witness_difference(rd.char(0), rd.Epsilon) is b''
def test_lexmin_of_star_is_empty():
assert rd.lexmin(rd.star(rd.char(b'0'))) is b''
def test_subtraction_from_empty_is_empty():
x = rd.char(0)
assert rd.subtract(rd.Empty, x) is rd.Empty
def test_union_of_infinite_and_finite_is_infinite():
assert rd.is_infinite(rd.union(rd.char(1), rd.star(rd.char(0))))
def test_subtraction_from_epsilon_checks_nullability():
assert rd.subtract(rd.Epsilon, rd.char(0)) is rd.Epsilon
assert rd.subtract(rd.Epsilon, rd.star(rd.char(0))) is rd.Empty
def test_bounded_is_not_infinite():
assert not rd.is_infinite(rd.bounded(rd.star(rd.char(0)), 10 ** 6))
def test_flattens_unions():
x = rd.star(rd.char(0))
y = rd.star(rd.char(1))
z = rd.star(rd.char(2))
assert rd.union(x, rd.union(y, z)) is rd.union(rd.union(x, z), y)
def test_non_empty_star_dfa():
accepting, _ = rd.build_dfa(rd.nonempty(rd.star(rd.char(0))))
assert accepting == [False, True]
def test_derivatives_of_unions():
assert rd.derivative(
rd.union(rd.star(rd.char(0)), rd.star(rd.char(1))), 0
) is rd.star(rd.char(0))
def test_trival_dfa_from_intersection():
assert rd.build_dfa(
rd.intersection(rd.char(b'\x00'), rd.char(b'\x00\x01'))) == (
[False, True], [{0: 1}, {}]
)
def test_flattens_intersections():
x = rd.star(rd.char(b'01'))
y = rd.star(rd.char(b'02'))
z = rd.star(rd.char(b'03'))
assert rd.intersection(x, rd.intersection(y, z)) is \
rd.intersection(rd.intersection(x, z), y)
