spot/tests/python/stutter.py
Alexandre Duret-Lutz b5d688dc97 stutter: fix sl, sl2 to never accept on added self-loop
Fixes #401, reported by Victor Khomenko.

* spot/twaalgos/stutter.cc (sl, sl2): If {} is accepting, upgrade the
acceptance condition.
* tests/core/stutter-tgba.test, tests/python/stutter.py: Add test cases.
2020-03-12 21:54:13 +01:00

62 lines
2.2 KiB
Python

# -*- mode: python; coding: utf-8 -*-
# Copyright (C) 2019, 2020 Laboratoire de Recherche et Développement de
# l'Epita (LRDE).
#
# This file is part of Spot, a model checking library.
#
# Spot is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# Spot is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
# License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
# Test that the spot.gen package works, in particular, we want
# to make sure that the objects created from spot.gen methods
# are usable with methods from the spot package.
import spot
def explain_stut(f):
f = spot.formula(f)
pos = spot.translate(f)
neg = spot.translate(spot.formula.Not(f))
word = spot.product(spot.closure(pos), spot.closure(neg)).accepting_word()
if word is None:
print(f, "is stutter invariant")
return
word.simplify()
# This line used to be missing, causing issue #388.
word.use_all_aps(pos.ap_vars())
waut = word.as_automaton()
aut = neg if waut.intersects(pos) else pos
word2 = spot.sl2(waut).intersecting_word(aut)
word2.simplify()
return(word, word2)
# Test from issue #388
w1, w2 = explain_stut('{(a:b) | (a;b)}|->Gc')
assert str(w1) == 'a & !b & !c; cycle{!a & b & !c}'
assert str(w2) == 'a & !b & !c; a & !b & !c; cycle{!a & b & !c}'
# Test from issue #401
w1, w2 = explain_stut('G({x} |-> ({x[+]} <>-> ({Y1[+]} <>=> Y2)))')
assert str(w1) == 'cycle{!Y1 & !Y2 & x; Y1 & Y2 & x}'
assert str(w2) == 'cycle{!Y1 & !Y2 & x; Y1 & Y2 & x; Y1 & Y2 & x}'
# Related to issue #401 as well. sl() and sl2() should upgrade
# the t acceptance condition into inf(0).
pos = spot.translate('Xa & XXb')
w = pos.accepting_word().as_automaton()
assert w.acc().is_t()
assert not spot.sl2(w).acc().is_buchi()
assert not spot.sl(w).acc().is_buchi()