fix: allow a list of machines in "parallel" and thus initial to be a …

…(list of) machines

- part of #507
- note that machine states must be unique!

tests/test_parallel.py

@@ -263,6 +263,14 @@ def test_is_state_parallel(self):
         assert m.is_P_2(allow_substates=True)
         assert not m.is_A(allow_substates=True)
 
+    def test_reuse(self):
+        a = self.machine_cls(states=["A", "B"], initial="A")
+        b = self.machine_cls(states=["C", "D"], initial="D")
+        c = self.machine_cls(states=["A", {"name": "X", "parallel": [a, b]}], initial="A")
+        assert c.to_X()
+        assert c.state == ["X{}A".format(self.state_cls.separator),
+                           "X{}D".format(self.state_cls.separator)]
+
 
 @skipIf(pgv is None, "pygraphviz is not available")
 class TestParallelWithPyGraphviz(TestParallel):

transitions/extensions/nesting.py

@@ -966,6 +966,7 @@ def _add_dict_state(self, state, ignore_invalid_triggers, remap, **kwargs):
         if state_parallel:
             state_children = state_parallel
             state['initial'] = [s['name'] if isinstance(s, dict)
+                                else s.initial if isinstance(s, HierarchicalMachine)
                                 else s for s in state_children]
         else:
             state_children = state.pop('children', state.pop('states', []))