Merge pull request #239 from Synss/graphing-nameless-callable

Fix graph crash with partial conditions

tests/test_core.py

@@ -5,6 +5,7 @@
 
 from .utils import InheritedStuff
 from .utils import Stuff
+from functools import partial
 import sys
 from transitions import Machine, MachineError, State, EventData
 from transitions.core import listify, prep_ordered_arg
@@ -130,6 +131,24 @@ def test_conditions(self):
         s.advance()
         self.assertEqual(s.state, 'C')
 
+    def test_conditions_with_partial(self):
+        def check(result):
+            return result
+
+        s = self.stuff
+        s.machine.add_transition('advance', 'A', 'B',
+                                 conditions=partial(check, True))
+        s.machine.add_transition('advance', 'B', 'C',
+                                 unless=[partial(check, False)])
+        s.machine.add_transition('advance', 'C', 'D',
+                                 unless=[partial(check, False), partial(check, True)])
+        s.advance()
+        self.assertEqual(s.state, 'B')
+        s.advance()
+        self.assertEqual(s.state, 'C')
+        s.advance()
+        self.assertEqual(s.state, 'C')
+
     def test_multiple_add_transitions_from_state(self):
         s = self.stuff
         s.machine.add_transition(

tests/test_graphing.py

@@ -6,9 +6,10 @@
 from .utils import Stuff
 
 from transitions.extensions import MachineFactory
-from transitions.extensions.diagrams import Diagram
+from transitions.extensions.diagrams import Diagram, rep
 from transitions.extensions.nesting import NestedState
 from unittest import TestCase, skipIf
+from functools import partial
 import tempfile
 import os
 
@@ -23,6 +24,61 @@ def edge_label_from_transition_label(label):
     return label.split(' | ')[0].split(' [')[0]  # if no condition, label is returned; returns first event only
 
 
+class TestRep(TestCase):
+
+    def test_rep_string(self):
+        self.assertEqual(rep("string"), "string")
+
+    def test_rep_function(self):
+        def check():
+            return True
+        self.assertTrue(check())
+        self.assertEqual(rep(check), "check")
+
+    def rest_rep_partial_no_args_no_kwargs(self):
+        def check():
+            return True
+        pcheck = partial(check)
+        self.assertTrue(pcheck())
+        self.assertEqual(rep(pcheck), "check()")
+
+    def test_rep_partial_with_args(self):
+        def check(result):
+            return result
+        pcheck = partial(check, True)
+        self.assertTrue(pcheck())
+        self.assertEqual(rep(pcheck), "check(True)")
+
+    def test_rep_partial_with_kwargs(self):
+        def check(result=True):
+            return result
+        pcheck = partial(check, result=True)
+        self.assertTrue(pcheck())
+        self.assertEqual(rep(pcheck), "check(result=True)")
+
+    def test_rep_partial_with_args_and_kwargs(self):
+        def check(result, doublecheck=True):
+            return result == doublecheck
+        pcheck = partial(check, True, doublecheck=True)
+        self.assertTrue(pcheck())
+        self.assertEqual(rep(pcheck), "check(True, doublecheck=True)")
+
+    def test_rep_callable_class(self):
+        class Check(object):
+            def __init__(self, result):
+                self.result = result
+
+            def __call__(self):
+                return self.result
+
+            def __repr__(self):
+                return "%s(%r)" % (type(self).__name__, self.result)
+
+        ccheck = Check(True)
+        self.assertTrue(ccheck())
+        self.assertEqual(rep(ccheck), "Check(True)")
+
+
 @skipIf(pgv is None, 'Graph diagram requires pygraphviz')
 class TestDiagrams(TestCase):
 

transitions/extensions/diagrams.py

@@ -10,10 +10,30 @@
 
 import logging
 from functools import partial
+import itertools
+from six import string_types, iteritems
 logger = logging.getLogger(__name__)
 logger.addHandler(logging.NullHandler())
 
 
+def rep(f):
+    """Return a string representation for `f`."""
+    if isinstance(f, string_types):
+        return f
+    try:
+        return f.__name__
+    except AttributeError:
+        pass
+    if isinstance(f, partial):
+        return "%s(%s)" % (
+            f.func.__name__,
+            ", ".join(itertools.chain(
+                (str(_) for _ in f.args),
+                ("%s=%s" % (key, value)
+                 for key, value in iteritems(f.keywords if f.keywords else {})))))
+    return str(f)
+
+
 class Diagram(object):
 
     def __init__(self, machine):
@@ -116,15 +136,12 @@ def _is_auto_transition(self, event, label):
                 return True
         return False
 
-    def rep(self, f):
-        return f.__name__ if callable(f) else f
-
     def _transition_label(self, edge_label, tran):
         if self.machine.show_conditions and tran.conditions:
             return '{edge_label} [{conditions}]'.format(
                 edge_label=edge_label,
                 conditions=' & '.join(
-                    self.rep(c.func) if c.target else '!' + self.rep(c.func)
+                    rep(c.func) if c.target else '!' + rep(c.func)
                     for c in tran.conditions
                 ),
             )