tgba: Implement a tgbagraph subclass

* src/tgba/tgbagraph.hh: New file.
* src/tgba/Makefile.am: Add it.
* src/graph/graph.hh: Add methods needed by tgbagraph.hh.
* src/graphtest/tgbagraph.cc, src/graphtest/tgbagraph.test: New files.
* src/graphtest/Makefile.am: Add them.

src/graphtest/tgbagraph.test

@@ -0,0 +1,52 @@
+#!/bin/sh
+# -*- coding: utf-8 -*-
+# Copyright (C) 2014 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/>.
+
+# While running some benchmark, Tomáš Babiak found that Spot took too
+# much time (i.e. >1h) to translate those six formulae.  It turns out
+# that the WDBA minimization was performed after the degeneralization
+# algorithm, while this is not necessary (WDBA will produce a BA, so
+# we may as well skip degeneralization).  Translating these formulae
+# in the test-suite ensure that they don't take too much time (the
+# buildfarm will timeout if it does).
+
+. ./defs
+
+set -e
+
+run 0 ../tgbagraph | tee stdout
+
+cat >expected <<EOF
+digraph G {
+  0 [label="", style=invis, height=0]
+  0 -> 1
+  1 [label="0"]
+  1 -> 2 [label="p1\n"]
+  1 -> 3 [label="p2\n{Acc[p2]}"]
+  2 [label="1"]
+  2 -> 3 [label="p1 & p2\n{Acc[p1]}"]
+  3 [label="2"]
+  3 -> 1 [label="p1 | p2\n{Acc[p2], Acc[p1]}"]
+  3 -> 2 [label="!p1 | p2\n"]
+  3 -> 3 [label="1\n{Acc[p2], Acc[p1]}"]
+}
+EOF
+
+diff stdout expected
+