diff --git a/README b/README
index b6d127ee5..73e549914 100644
--- a/README
+++ b/README
@@ -148,6 +148,8 @@ src/              Sources for libspot.
    dstarparse/    Parser for the output of ltl2dstar.
    eltlparse/     Parser for ELTL formulae.
    eltltest/      Tests for ELTL nodes in ltlast/ and eltlparse/.
+   graph/         Graph representations.
+   graphtest/     Graph representations.
    kripke/        Kripke Structure interface.
    kripkeparse/   Parser for explicit Kripke.
    kripketest/    Tests for kripke explicit.
diff --git a/configure.ac b/configure.ac
index 2970c4acc..9410b3fac 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,9 +1,9 @@
 # -*- coding: utf-8 -*-
 # Copyright (C) 2008, 2009, 2010, 2011, 2012, 2013, 2014 Laboratoire
 # de Recherche et Développement de l'Epita (LRDE).
-# Copyright (C) 2003, 2004, 2005, 2006, 2007 Laboratoire d'Informatique de
-# Paris 6 (LIP6), département Systèmes Répartis Coopératifs (SRC), Université
-# Pierre et Marie Curie.
+# Copyright (C) 2003, 2004, 2005, 2006, 2007 Laboratoire
+# d'Informatique de Paris 6 (LIP6), département Systèmes Répartis
+# Coopératifs (SRC), Université Pierre et Marie Curie.
 #
 # This file is part of Spot, a model checking library.
 #
@@ -181,6 +181,9 @@ AC_CONFIG_FILES([
   src/eltltest/defs
   src/eltltest/Makefile
   src/kripke/Makefile
+  src/graph/Makefile
+  src/graphtest/Makefile
+  src/graphtest/defs
   src/ltlast/Makefile
   src/ltlenv/Makefile
   src/ltlparse/Makefile
diff --git a/src/Makefile.am b/src/Makefile.am
index a7aba7799..5a2302b22 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,6 +1,6 @@
 ## -*- coding: utf-8 -*-
-## Copyright (C) 2009, 2010, 2012, 2013 Laboratoire de Recherche et
-## Développement de l'Epita (LRDE).
+## Copyright (C) 2009, 2010, 2012, 2013, 2014 Laboratoire de Recherche
+## et Développement de l'Epita (LRDE).
 ## Copyright (C) 2003, 2004 Laboratoire d'Informatique de Paris 6 (LIP6),
 ## département Systèmes Répartis Coopératifs (SRC), Université Pierre
 ## et Marie Curie.
@@ -25,10 +25,10 @@ AUTOMAKE_OPTIONS = subdir-objects
 # List directories in the order they must be built.  Keep tests at the
 # end, after building '.' (since the current directory contains
 # libspot.la needed by the tests)
-SUBDIRS = misc priv ltlenv ltlast ltlvisit ltlparse eltlparse tgba	\
-          tgbaalgos tgbaparse ta taalgos kripke saba sabaalgos		\
+SUBDIRS = misc priv ltlenv ltlast ltlvisit ltlparse eltlparse graph	\
+          tgba tgbaalgos tgbaparse ta taalgos kripke saba sabaalgos	\
           neverparse kripkeparse dstarparse . bin ltltest eltltest	\
-          tgbatest sabatest kripketest sanity
+          graphtest tgbatest sabatest kripketest sanity
 
 lib_LTLIBRARIES = libspot.la
 libspot_la_SOURCES =
diff --git a/src/graph/Makefile.am b/src/graph/Makefile.am
new file mode 100644
index 000000000..858cc6980
--- /dev/null
+++ b/src/graph/Makefile.am
@@ -0,0 +1,27 @@
+## -*- 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/>.
+
+
+AM_CPPFLAGS = -I$(srcdir)/..
+AM_CXXFLAGS = $(WARNING_CXXFLAGS)
+
+graphdir = $(pkgincludedir)/graph
+
+graph_HEADERS = \
+  graph.hh
diff --git a/src/graph/graph.hh b/src/graph/graph.hh
new file mode 100644
index 000000000..17c1356cc
--- /dev/null
+++ b/src/graph/graph.hh
@@ -0,0 +1,371 @@
+// -*- coding: utf-8 -*-
+// Copyright (C) 2014 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/>.
+
+#ifndef SPOT_GRAPH_GRAPH_HH
+# define SPOT_GRAPH_GRAPH_HH
+
+#include <vector>
+#include <type_traits>
+#include <tuple>
+
+
+namespace spot
+{
+  template <typename State_Data, typename Trans_Data, bool Alternating = false>
+  class digraph;
+
+  namespace internal
+  {
+    // The boxed_label class stores Data as an attribute called
+    // "label" if boxed is true.  It is an empty class if Data is
+    // void, and it simply inherits from Data if boxed is false.
+    //
+    // The data() method offers an homogeneous access to the Data
+    // instance.
+
+    template <typename Data, bool boxed = !std::is_class<Data>::value>
+    struct boxed_label
+    {
+      Data label;
+
+      template <typename... Args>
+      boxed_label(Args&&... args):
+	label{std::forward<Args>(args)...}
+      {
+      }
+
+      // if Data is a POD type, G++ 4.8.2 wants default values for all
+      // label fields unless we define this default constructor here.
+      explicit boxed_label()
+      {
+      }
+
+      Data& data()
+      {
+	return label;
+      }
+
+      const Data& data() const
+      {
+	return label;
+      }
+    };
+
+    template <>
+    struct boxed_label<void, true>
+    {
+    };
+
+    template <typename Data>
+    struct boxed_label<Data, false>: public Data
+    {
+      template <typename... Args>
+      boxed_label(Args&&... args):
+	Data{std::forward<Args>(args)...}
+      {
+      }
+
+      // if Data is a POS type, G++ 4.8.2 wants default values for all
+      // label fields unless we define this default constructor here.
+      explicit boxed_label()
+      {
+      }
+
+      Data& data()
+      {
+	return *this;
+      }
+
+      const Data& data() const
+      {
+	return *this;
+      }
+    };
+
+    //////////////////////////////////////////////////
+    // State storage for digraphs
+    //////////////////////////////////////////////////
+
+    // We have two implementations, one with attached State_Data, and
+    // one without.
+
+    template <typename Transition, typename State_Data>
+    struct distate_storage: public State_Data
+    {
+      Transition succ; // First outgoing transition (used when iterating)
+      Transition succ_tail;	// Last outgoing transition (used for
+				// appending new transitions)
+
+      template <typename... Args>
+      distate_storage(Args&&... args):
+	State_Data{std::forward<Args>(args)...},
+	succ(0),
+	succ_tail(0)
+      {
+      }
+    };
+
+    //////////////////////////////////////////////////
+    // Transition storage
+    //////////////////////////////////////////////////
+
+    // Again two implementation: one with label, and one without.
+
+    template <typename State, typename Transition, typename Trans_Data>
+    struct trans_storage: public Trans_Data
+    {
+      typedef Transition transition;
+
+      State dst;		// destination
+      Transition next_succ;	// next outgoing transition with same
+				// source, or 0
+      explicit trans_storage()
+	: Trans_Data{}
+      {
+      }
+
+      template <typename... Args>
+      trans_storage(State dst, Transition next_succ, Args&&... args)
+	: Trans_Data{std::forward<Args>(args)...},
+	  dst(dst), next_succ(next_succ)
+      {
+      }
+    };
+
+    //////////////////////////////////////////////////
+    // Transition iterator
+    //////////////////////////////////////////////////
+
+    // This holds a graph and a transition number that is the start of
+    // a list, and it iterates over all the trans_storage_t elements
+    // of that list.
+
+    template <typename Graph>
+    class trans_iterator
+    {
+    public:
+      typedef typename Graph::transition transition;
+      typedef typename Graph::trans_storage_t trans_storage_t;
+
+      trans_iterator(Graph* g, transition t): t_(t), g_(g)
+      {
+      }
+
+      bool operator==(trans_iterator o)
+      {
+	return t_ == o.t_;
+      }
+
+      bool operator!=(trans_iterator o)
+      {
+	return t_ != o.t_;
+      }
+
+      typename std::conditional<std::is_const<Graph>::value,
+				const trans_storage_t&,
+				trans_storage_t&>::type
+      operator*()
+      {
+	return g_->transitions_[t_];
+      }
+
+      trans_iterator operator++()
+      {
+	t_ = operator*().next_succ;
+	return *this;
+      }
+
+      trans_iterator operator++(int)
+      {
+	trans_iterator ti = *this;
+	t_ = operator*().next_succ;
+	return ti;
+      }
+
+    protected:
+      transition t_;
+      Graph* g_;
+    };
+
+    //////////////////////////////////////////////////
+    // State OUT
+    //////////////////////////////////////////////////
+
+    // Fake container listing the outgoing transitions of a state.
+
+    template <typename Graph>
+    class state_out
+    {
+    public:
+      typedef typename Graph::transition transition;
+      state_out(Graph* g, transition t):
+	t_(t), g_(g)
+      {
+      }
+
+      trans_iterator<Graph> begin()
+      {
+	return {g_, t_};
+      }
+
+      trans_iterator<Graph> end()
+      {
+	return {nullptr, 0};
+      }
+
+    protected:
+      transition t_;
+      Graph* g_;
+    };
+
+  }
+
+  // The actual graph implementation
+
+  template <typename State_Data, typename Trans_Data, bool Alternating>
+  class digraph
+  {
+    friend class internal::trans_iterator<digraph>;
+    friend class internal::trans_iterator<const digraph>;
+  public:
+    static constexpr bool alternating()
+    {
+      return Alternating;
+    }
+
+    // Extra data to store on each state or transition.
+    typedef State_Data state_data_t;
+    typedef Trans_Data trans_data_t;
+
+    // State and transitions are identified by their indices in some
+    // vector.
+    typedef unsigned state;
+    typedef unsigned transition;
+
+    // The type of an output state (when seen from a transition)
+    // depends on the kind of graph we build
+    typedef typename std::conditional<Alternating,
+				      std::vector<state>,
+				      state>::type out_state;
+
+    typedef internal::distate_storage<transition,
+				      internal::boxed_label<State_Data>>
+      state_storage_t;
+    typedef internal::trans_storage<out_state, transition,
+				    internal::boxed_label<Trans_Data>>
+      trans_storage_t;
+    typedef std::vector<state_storage_t> state_vector;
+    typedef std::vector<trans_storage_t> trans_vector;
+  protected:
+    state_vector states_;
+    trans_vector transitions_;
+
+  public:
+    /// \brief construct an empty graph
+    ///
+    /// Construct an empty graph, and reserve space for \a max_states
+    /// states and \a max_trans transitions.  These are not hard
+    /// limits, but just hints to pre-allocate a data structure that
+    /// may hold that much items.
+    digraph(unsigned max_states = 10, unsigned max_trans = 0)
+    {
+      states_.reserve(max_states);
+      if (max_trans == 0)
+	max_trans = max_states * 2;
+      transitions_.reserve(max_trans + 1);
+      // Transition number 0 is not used, because we use this index
+      // to mark the absence of a transition.
+      transitions_.resize(1);
+    }
+
+    template <typename... Args>
+    state new_state(Args&&... args)
+    {
+      state s = states_.size();
+      states_.emplace_back(std::forward<Args>(args)...);
+      return s;
+    }
+
+    // May not be called on states with no data.
+    State_Data
+    state_data(state s)
+    {
+      return states_[s].data();
+    }
+
+    // May not be called on states with no data.
+    State_Data
+    state_data(state s) const
+    {
+      return states_[s].data();
+    }
+
+    template <typename... Args>
+    transition
+    new_transition(state src, out_state dst, Args&&... args)
+    {
+      transition t = transitions_.size();
+      transitions_.emplace_back(dst, 0, std::forward<Args>(args)...);
+
+      transition st = states_[src].succ_tail;
+      if (!st)
+	states_[src].succ = t;
+      else
+	transitions_[st].next_succ = t;
+      states_[src].succ_tail = t;
+      return t;
+    }
+
+    internal::state_out<digraph>
+    out(state src)
+    {
+      return {this, states_[src].succ};
+    }
+
+    internal::state_out<const digraph>
+    out(state src) const
+    {
+      return {this, states_[src].succ};
+    }
+
+    unsigned nb_states() const
+    {
+      return states_.size();
+    }
+
+    unsigned nb_trans() const
+    {
+      return transitions_.size();
+    }
+
+    const state_vector& states() const
+    {
+      return states_;
+    }
+
+    state_vector& states()
+    {
+      return states_;
+    }
+
+  };
+
+}
+
+#endif // SPOT_GRAPH_GRAPH_HH
diff --git a/src/graphtest/.gitignore b/src/graphtest/.gitignore
new file mode 100644
index 000000000..7fd396885
--- /dev/null
+++ b/src/graphtest/.gitignore
@@ -0,0 +1,2 @@
+graphtest
+defs
diff --git a/src/graphtest/Makefile.am b/src/graphtest/Makefile.am
new file mode 100644
index 000000000..f1c5ba60d
--- /dev/null
+++ b/src/graphtest/Makefile.am
@@ -0,0 +1,34 @@
+## -*- 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/>.
+
+
+AM_CPPFLAGS = -I$(srcdir)/.. -I.. $(BUDDY_CPPFLAGS)
+AM_CXXFLAGS = $(WARNING_CXXFLAGS)
+LDADD = ../libspot.la
+
+noinst_PROGRAMS = graph
+
+graph_SOURCES = graph.cc
+
+TESTS = graph.test
+
+EXTRA_DIST = $(TESTS)
+
+distclean-local:
+	rm -rf $(TESTS:.test=.dir)
diff --git a/src/graphtest/defs.in b/src/graphtest/defs.in
new file mode 100644
index 000000000..5169462fe
--- /dev/null
+++ b/src/graphtest/defs.in
@@ -0,0 +1,85 @@
+# -*- mode: shell-script; coding: utf-8 -*-
+# Copyright (C) 2009, 2010, 2012, 2013, 2014 Laboratoire de Recherche
+# et Développement de l'Epita (LRDE).
+# Copyright (C) 2003, 2004, 2006 Laboratoire d'Informatique de Paris 6
+# (LIP6), département Systèmes Répartis Coopératifs (SRC), Université
+# Pierre et Marie Curie.
+#
+# This file is part of Spot, a model checking library.
+#
+# Spot is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# Spot is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+# or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+# License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Ensure we are running from the right directory.
+test -f ./defs || {
+   echo "defs: not found in current directory" 1>&2
+   exit 1
+}
+
+# If srcdir is not set, then we are not running from `make check'.
+if test -z "$srcdir"; then
+   # compute $srcdir.
+   srcdir=`echo "$0" | sed -e 's,/[^\\/]*$,,'`
+   test $srcdir = $0 && srcdir=.
+fi
+
+# Ensure $srcdir is set correctly.
+test -f $srcdir/defs.in || {
+   echo "$srcdir/defs.in not found, check \$srcdir" 1>&2
+   exit 1
+}
+
+echo "== Running test $0"
+
+me=`echo "$0" | sed -e 's,.*[\\/],,;s/\.test$//'`
+
+testSubDir=$me.dir
+chmod -R a+rwx $testSubDir > /dev/null 2>&1
+rm -rf $testSubDir > /dev/null 2>&1
+mkdir $testSubDir
+cd $testSubDir
+
+# Adjust srcdir now that we are in a subdirectory.  We still want
+# $srcdir to point to the source directory corresponding to the build
+# directory that contains $testSubDir.
+case $srcdir in
+  [\\/$]* | ?:[\\/]* );;
+  *) srcdir=../$srcdir
+esac
+
+DOT='@DOT@'
+top_builddir='../@top_builddir@'
+VALGRIND='@VALGRIND@'
+PYTHON='@PYTHON@'
+
+run()
+{
+  expected_exitcode=$1
+  shift
+  exitcode=0
+  if test -n "$VALGRIND"; then
+    exec 6>valgrind.err
+    GLIBCPP_FORCE_NEW=1 \
+    ../../../libtool --mode=execute \
+    $VALGRIND --tool=memcheck --leak-check=yes --log-fd=6 -q "$@" ||
+      exitcode=$?
+    cat valgrind.err 1>&2
+    test -z "`sed 1q valgrind.err`" || exit 50
+    rm -f valgrind.err
+  else
+    "$@" || exitcode=$?
+  fi
+  test $exitcode = $expected_exitcode || exit 1
+}
+
+set -x
diff --git a/src/graphtest/graph.cc b/src/graphtest/graph.cc
new file mode 100644
index 000000000..4a7d0bbc9
--- /dev/null
+++ b/src/graphtest/graph.cc
@@ -0,0 +1,312 @@
+// -*- coding: utf-8 -*-
+// Copyright (C) 2014 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/>.
+
+
+#include <iostream>
+#include "graph/graph.hh"
+
+template <typename SL, typename TL>
+void
+dot_state(std::ostream& out, spot::digraph<SL, TL>& g, unsigned n)
+{
+  out << " [label=\"" << g.state_data(n) << "\"]\n";
+}
+
+template <typename TL>
+void
+dot_state(std::ostream& out, spot::digraph<void, TL>&, unsigned)
+{
+  out << '\n';
+}
+
+template <typename SL, typename TL, typename TR>
+void
+dot_trans(std::ostream& out, spot::digraph<SL, TL>&, TR& tr)
+{
+  out << " [label=\"" << tr.data() << "\"]\n";
+}
+
+template <typename SL, typename TR>
+void
+dot_trans(std::ostream& out, spot::digraph<SL, void>&, TR&)
+{
+  out << '\n';
+}
+
+
+template <typename SL, typename TL>
+void
+dot(std::ostream& out, spot::digraph<SL, TL>& g)
+{
+  out << "digraph {\n";
+  unsigned c = g.nb_states();
+  for (unsigned s = 0; s < c; ++s)
+    {
+      out << ' ' << s;
+      dot_state(out, g, s);
+      for (auto& t: g.out(s))
+	{
+	  out << ' ' << s << " -> " << t.dst;
+	  dot_trans(out, g, t);
+	}
+    }
+  out << "}\n";
+}
+
+
+bool g1(const spot::digraph<void, void>& g,
+	unsigned s, int e)
+{
+  int f = 0;
+  for (auto& t: g.out(s))
+    {
+      (void) t;
+      ++f;
+    }
+  return f == e;
+}
+
+bool f1()
+{
+  spot::digraph<void, void> g(3);
+
+  auto s1 = g.new_state();
+  auto s2 = g.new_state();
+  auto s3 = g.new_state();
+  g.new_transition(s1, s2);
+  g.new_transition(s1, s3);
+  g.new_transition(s2, s3);
+  g.new_transition(s3, s1);
+  g.new_transition(s3, s2);
+  g.new_transition(s3, s3);
+
+  dot(std::cout, g);
+
+  int f = 0;
+  for (auto& t: g.out(s1))
+    {
+      (void) t;
+      ++f;
+    }
+  return f == 2
+    && g1(g, s3, 3)
+    && g1(g, s2, 1)
+    && g1(g, s1, 2);
+}
+
+
+bool f2()
+{
+  spot::digraph<int, void> g(3);
+
+  auto s1 = g.new_state(1);
+  auto s2 = g.new_state(2);
+  auto s3 = g.new_state(3);
+  g.new_transition(s1, s2);
+  g.new_transition(s1, s3);
+  g.new_transition(s2, s3);
+  g.new_transition(s3, s2);
+
+  dot(std::cout, g);
+
+  int f = 0;
+  for (auto& t: g.out(s1))
+    {
+      f += g.state_data(t.dst);
+    }
+  return f == 5;
+}
+
+bool f3()
+{
+  spot::digraph<void, int> g(3);
+
+  auto s1 = g.new_state();
+  auto s2 = g.new_state();
+  auto s3 = g.new_state();
+  g.new_transition(s1, s2, 1);
+  g.new_transition(s1, s3, 2);
+  g.new_transition(s2, s3, 3);
+  g.new_transition(s3, s2, 4);
+
+  dot(std::cout, g);
+
+  int f = 0;
+  for (auto& t: g.out(s1))
+    {
+      f += t.label;
+    }
+  return f == 3 && g.states().size() == 3;
+}
+
+bool f4()
+{
+  spot::digraph<int, int> g(3);
+
+  auto s1 = g.new_state(2);
+  auto s2 = g.new_state(3);
+  auto s3 = g.new_state(4);
+  g.new_transition(s1, s2, 1);
+  g.new_transition(s1, s3, 2);
+  g.new_transition(s2, s3, 3);
+  g.new_transition(s3, s2, 4);
+
+  dot(std::cout, g);
+
+  int f = 0;
+  for (auto& t: g.out(s1))
+    {
+      f += t.label * g.state_data(t.dst);
+    }
+  return f == 11;
+}
+
+bool f5()
+{
+  spot::digraph<void, std::pair<int, float>> g(3);
+
+  auto s1 = g.new_state();
+  auto s2 = g.new_state();
+  auto s3 = g.new_state();
+  g.new_transition(s1, s2, std::make_pair(1, 1.2f));
+  g.new_transition(s1, s3, std::make_pair(2, 1.3f));
+  g.new_transition(s2, s3, std::make_pair(3, 1.4f));
+  g.new_transition(s3, s2, std::make_pair(4, 1.5f));
+
+  int f = 0;
+  float h = 0;
+  for (auto& t: g.out(s1))
+    {
+      f += std::get<0>(t);
+      h += std::get<1>(t);
+    }
+  return f == 3 && (h > 2.49 && h < 2.51);
+}
+
+bool f6()
+{
+  spot::digraph<void, std::pair<int, float>> g(3);
+
+  auto s1 = g.new_state();
+  auto s2 = g.new_state();
+  auto s3 = g.new_state();
+  g.new_transition(s1, s2, 1, 1.2f);
+  g.new_transition(s1, s3, 2, 1.3f);
+  g.new_transition(s2, s3, 3, 1.4f);
+  g.new_transition(s3, s2, 4, 1.5f);
+
+  int f = 0;
+  float h = 0;
+  for (auto& t: g.out(s1))
+    {
+      f += t.first;
+      h += t.second;
+    }
+  return f == 3 && (h > 2.49 && h < 2.51);
+}
+
+bool f7()
+{
+  spot::digraph<int, int, true> g(3);
+  auto s1 = g.new_state(2);
+  auto s2 = g.new_state(3);
+  auto s3 = g.new_state(4);
+  g.new_transition(s1, {s2, s3}, 1);
+  g.new_transition(s1, {s3}, 2);
+  g.new_transition(s2, {s3}, 3);
+  g.new_transition(s3, {s2}, 4);
+
+  int f = 0;
+  for (auto& t: g.out(s1))
+    {
+      for (auto& tt: t.dst)
+	{
+	  f += t.label * g.state_data(tt);
+	}
+    }
+  return f == 15;
+}
+
+
+struct int_pair
+{
+  int one;
+  int two;
+
+  friend std::ostream& operator<<(std::ostream& os, int_pair p)
+  {
+    os << '(' << p.one << ',' << p.two << ')';
+    return os;
+  }
+
+#if __GNUC__ <= 4 && __GNUC_MINOR__ <= 6
+  int_pair(int one, int two)
+    : one(one), two(two)
+  {
+  }
+
+  int_pair()
+  {
+  }
+#endif
+};
+
+bool f8()
+{
+  spot::digraph<int_pair, int_pair> g(3);
+  auto s1 = g.new_state(2, 4);
+  auto s2 = g.new_state(3, 6);
+  auto s3 = g.new_state(4, 8);
+  g.new_transition(s1, s2, 1, 3);
+  g.new_transition(s1, s3, 2, 5);
+  g.new_transition(s2, s3, 3, 7);
+  g.new_transition(s3, s2, 4, 9);
+
+  dot(std::cout, g);
+
+  int f = 0;
+  for (auto& t: g.out(s1))
+    {
+      f += t.one * g.state_data(t.dst).one;
+      f += t.two * g.state_data(t.dst).two;
+    }
+  return f == 69;
+}
+
+
+int main()
+{
+  bool a1 = f1();
+  bool a2 = f2();
+  bool a3 = f3();
+  bool a4 = f4();
+  bool a5 = f5();
+  bool a6 = f6();
+  bool a7 = f7();
+  bool a8 = f8();
+  std::cout << a1 << ' '
+	    << a2 << ' '
+	    << a3 << ' '
+	    << a4 << ' '
+	    << a5 << ' '
+	    << a6 << ' '
+	    << a7 << ' '
+	    << a8 << '\n';
+  return !(a1 && a2 && a3 && a4 && a5 && a6 && a7 && a8);
+}
diff --git a/src/graphtest/graph.test b/src/graphtest/graph.test
new file mode 100755
index 000000000..ca1c199a8
--- /dev/null
+++ b/src/graphtest/graph.test
@@ -0,0 +1,87 @@
+#!/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 ../graph > stdout
+
+cat >expected <<EOF
+digraph {
+ 0
+ 0 -> 1
+ 0 -> 2
+ 1
+ 1 -> 2
+ 2
+ 2 -> 0
+ 2 -> 1
+ 2 -> 2
+}
+digraph {
+ 0 [label="1"]
+ 0 -> 1
+ 0 -> 2
+ 1 [label="2"]
+ 1 -> 2
+ 2 [label="3"]
+ 2 -> 1
+}
+digraph {
+ 0
+ 0 -> 1 [label="1"]
+ 0 -> 2 [label="2"]
+ 1
+ 1 -> 2 [label="3"]
+ 2
+ 2 -> 1 [label="4"]
+}
+digraph {
+ 0 [label="2"]
+ 0 -> 1 [label="1"]
+ 0 -> 2 [label="2"]
+ 1 [label="3"]
+ 1 -> 2 [label="3"]
+ 2 [label="4"]
+ 2 -> 1 [label="4"]
+}
+digraph {
+ 0 [label="(2,4)"]
+ 0 -> 1 [label="(1,3)"]
+ 0 -> 2 [label="(2,5)"]
+ 1 [label="(3,6)"]
+ 1 -> 2 [label="(3,7)"]
+ 2 [label="(4,8)"]
+ 2 -> 1 [label="(4,9)"]
+}
+1 1 1 1 1 1 1 1
+EOF
+
+diff stdout expected
+