introduce check_determinism()

* spot/twaalgos/isdet.hh, spot/twaalgos/isdet.cc (check_determinism):
New function.
* NEWS: Mention it.
* tests/python/semidet.py: New file.
* tests/Makefile.am: Add it.

tests/python/semidet.py

@@ -0,0 +1,39 @@
+# -*- mode: python; coding: utf-8 -*-
+# Copyright (C) 2017 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/>.
+
+import spot
+
+formulas = [('(Gp0 | Fp1) M 1', False, True),
+            ('(!p1 U p1) U X(!p0 -> Fp1)', False, True),
+            ('(p1 | (Fp0 R (p1 W p0))) M 1', True, True),
+            ('!G(F(p1 & Fp0) W p1)', False, True),
+            ('X(!p0 W Xp1)', False, False),
+            ('FG(p0)', False, True) ]
+
+for f, isd, issd in formulas:
+    print(f)
+    aut = spot.translate(f)
+    # The formula with isd=True, issd=True is the only one
+    # for which both properties are already set.
+    assert (aut.prop_deterministic().is_maybe() or
+            aut.prop_semi_deterministic().is_maybe() or
+            isd == issd)
+    spot.check_determinism(aut)
+    assert aut.prop_deterministic() == isd
+    assert aut.prop_semi_deterministic() == issd