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 symdiff(x, y):
return rd.union(rd.subtract(x, y), rd.subtract(y, x))
def test_infinite_regex_have_more_than_one_solution(reg):
assume(rd.is_infinite(reg))
x = rd.subtract(reg, rd.literal(rd.lexmin(reg)))
assert rd.has_matches(x)
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_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_subtraction_from_empty_is_empty():
x = rd.char(0)
assert rd.subtract(rd.Empty, x) is rd.Empty
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
@given(regex())
def test_characters_in_same_class_produce_equivalent_expressions(re):
assume(rd.has_matches(re))
classes = rd.character_classes(re)
assume(any(len(cs) > 1 for cs in classes))
for cs in classes:
if len(cs) > 1:
derivs = [rd.derivative(re, c) for c in cs]
for a in derivs:
for b in derivs:
assert rd.equivalent(a, b)
@example(rd.star(rd.char(b'0')))
@example(rd.subtract(rd.star(rd.char(b'0')), rd.char(b'0')))
@given(regex())
def test_infinite_regex_have_more_than_one_solution(reg):
assume(rd.is_infinite(reg))
x = rd.subtract(reg, rd.literal(rd.lexmin(reg)))
assert rd.has_matches(x)
@example(rd.concatenate(rd.star(rd.char(b'\0')), rd.char(b'\1')))
@example(rd.union(rd.char(b'\0'), rd.star(rd.literal(b'\0\0'))))
@example(rd.star(rd.char(0)))
@given(regex())
def test_decompilation(re):
assume(rd.has_matches(re))
dfa = rd.build_dfa(re)
rewritten = rd.decompile_dfa(*dfa)
