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_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_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_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_self_intersection_is_identity():
x = rd.char(0)
assert rd.intersection(x, x, x) is x
def test_empty_kills_intersections():
assert rd.intersection(rd.Empty, rd.Epsilon) is rd.Empty
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_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)
@given(regex())
def test_decompilation(re):
assume(rd.has_matches(re))
dfa = rd.build_dfa(re)
rewritten = rd.decompile_dfa(*dfa)
assert rd.equivalent(re, rewritten)
def symdiff(x, y):
return rd.union(rd.subtract(x, y), rd.subtract(y, x))
@example(
rd.union(
rd.char(b'\x00'), rd.subtract(rd.star(rd.char(b'\x01')), rd.Epsilon)),
rd.intersection(rd.char(b'\x00'), rd.star(rd.char(b'\x00')))
)
@example(x=rd.literal(b'01'), y=rd.literal(b'11'))
@given(regex(), regex())
def test_lexmin_of_symmetric_difference_is_refutation(x, y):
assume(not rd.equivalent(x, y))
w = rd.lexmin(symdiff(x, y))
assert w is not None
assert w == rd.witness_difference(x, y)
@example(rd.union(rd.char(b'\0'), rd.star(rd.char(b'\x00'))))
@given(regex())
def test_no_refutation_for_decompilation(re):
dec = rd.decompile_dfa(*rd.build_dfa(re))
assert rd.witness_difference(dec, re) is None