scc_info: add Python bindings

Related to #172, where we discussed that scc_info bindings were
missing.

* spot/twaalgos/sccinfo.hh (spot::scc_info::scc_node): Move...
(spot::scc_info_node): ... here to help Swig.
* python/spot/impl.i: Add bindings for scc_info.
* tests/python/sccinfo.py: New file.
* tests/Makefile.am: Add it.

tests/python/sccinfo.py

@@ -0,0 +1,66 @@
+#!/usr/bin/python3
+# -*- mode: python; coding: utf-8 -*-
+# Copyright (C) 2017 Laboratoire de Recherche et Développement de
+# l'EPITA.
+#
+# 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
+
+a = spot.translate('(Ga -> Gb) W c')
+
+si = spot.scc_info(a)
+n = si.scc_count()
+assert n == 4
+
+acc = 0
+rej = 0
+triv = 0
+for i in range(n):
+    acc += si.is_accepting_scc(i)
+    rej += si.is_rejecting_scc(i)
+    triv += si.is_trivial(i)
+assert acc == 3
+assert rej == 1
+assert triv == 0
+
+for scc in si:
+    acc -= scc.is_accepting()
+    rej -= scc.is_rejecting()
+    triv -= scc.is_trivial()
+assert acc == 0
+assert rej == 0
+assert triv == 0
+
+l0 = si.states_of(0)
+l1 = si.states_of(1)
+l2 = si.states_of(2)
+l3 = si.states_of(3)
+l = sorted(list(l0) + list(l1) + list(l2) + list(l3))
+assert l == [0, 1, 2, 3, 4]
+
+i = si.initial()
+todo = {i}
+seen = {i}
+while todo:
+    e = todo.pop()
+    for s in si.succ(e):
+        if s not in seen:
+            seen.add(s)
+            todo.add(s)
+assert seen == {0, 1, 2, 3}
+
+assert not spot.is_weak_automaton(a, si)