History's memory cannot target itself

sismic/model/statechart.py

@@ -514,13 +514,15 @@ def _validate_compoundstate_initial(self):
 
     def _validate_historystate_memory(self):
         """
-        Checks that every *HistoryStateMixin*'s memory refer to one of its parent's children
+        Checks that every *HistoryStateMixin*'s memory refer to one of its parent's children, except itself.
 
         :return: True
         :raise StatechartError:
         """
         for name, state in self._states.items():
             if isinstance(state, HistoryStateMixin) and state.memory:
+                if state.memory == state.name:
+                    raise StatechartError('Initial memory {} of {} cannot target itself'.format(state.memory, state))
                 if state.memory not in self._states:
                     raise StatechartError('Initial memory {} of {} does not exist'.format(state.memory, state))
                 if state.memory not in self.children_for(self.parent_for(name)):

tests/test_model.py

@@ -109,27 +109,41 @@ def test_history_not_in_compound(self):
 
 class ValidateTests(unittest.TestCase):
     # REMARK: "Positive" tests are already done during io.import_from_yaml!
-    def test_history_memory(self):
+    def test_history_memory_not_child(self):
+        statechart = io.import_from_yaml(open('tests/yaml/history.yaml'))
+
+        statechart.state_for('loop.H').memory = 'pause'
+        with self.assertRaises(exceptions.StatechartError):
+            statechart._validate_historystate_memory()
+
+    def test_history_memory_unknown(self):
         statechart = io.import_from_yaml(open('tests/yaml/history.yaml'))
-        memory = statechart.state_for('loop.H').memory
 
         statechart.state_for('loop.H').memory = 'unknown'
-        with self.assertRaises(exceptions.StatechartError) as cm:
+        with self.assertRaises(exceptions.StatechartError):
             statechart._validate_historystate_memory()
 
-        statechart.state_for('loop.H').memory = memory
-        statechart._validate_historystate_memory()
+    def test_history_memory_self(self):
+        statechart = io.import_from_yaml(open('tests/yaml/history.yaml'))
+
+        statechart.state_for('loop.H').memory = 'loop.H'
+        with self.assertRaises(exceptions.StatechartError):
+            statechart._validate_historystate_memory()
 
-    def test_compound_initial(self):
+    def test_compound_initial_unknown(self):
         statechart = io.import_from_yaml(open('tests/yaml/composite.yaml'))
-        initial = statechart.state_for('s1b').initial
 
         statechart.state_for('s1b').initial = 'unknown'
-        with self.assertRaises(exceptions.StatechartError) as cm:
+        with self.assertRaises(exceptions.StatechartError):
+            statechart._validate_compoundstate_initial()
+
+    def test_compound_initial_not_child(self):
+        statechart = io.import_from_yaml(open('tests/yaml/composite.yaml'))
+
+        statechart.state_for('s1b').initial = 's1'
+        with self.assertRaises(exceptions.StatechartError):
             statechart._validate_compoundstate_initial()
 
-        statechart.state_for('s1b').initial = initial
-        statechart._validate_compoundstate_initial()
 
 
 class TransitionsTests(unittest.TestCase):