fix has_path returned value to include the destination node, else we get

an empty list which makes think there is no path (test added)

3 files changed, 21 insertions, 5 deletions

diff --git a/ChangeLog b/ChangeLog
index 2514e89..80406d4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -6,6 +6,8 @@ ChangeLog for logilab.common
       - proper bytes and time option types support
       - make Method usable as 'callback' value
       - fix #8849 Using plugins, options and .pylintrc crashes PyLint
+    * graph: fix has_path returned value to include the destination node, else we get
+      an empty list which makes think there is no path (test added)
 
 2009-08-26  --  0.45.0
     * added function for parsing XML processing instructions
diff --git a/graph.py b/graph.py
index c81887e..a6b7900 100644
--- a/graph.py
+++ b/graph.py
@@ -189,16 +189,16 @@ def has_path(graph_dict, fromnode, tonode, path=None):
     node has key associated to a list of nodes directly reachable from it.
 
     Return None if no path exists to go from `fromnode` to `tonode`, else the
-    first path found
+    first path found (as a list including the destination node at last)
     """
     if path is None:
         path = []
     elif fromnode in path:
-        return False
+        return None
     path.append(fromnode)
     for destnode in graph_dict[fromnode]:
         if destnode == tonode or has_path(graph_dict, destnode, tonode, path):
-            return path[1:]
+            return path[1:] + [tonode]
     path.pop()
     return None
 
diff --git a/test/unittest_graph.py b/test/unittest_graph.py
index b8f5394..ce272e5 100644
--- a/test/unittest_graph.py
+++ b/test/unittest_graph.py
@@ -1,9 +1,9 @@
 # unit tests for the cache module
 
 from logilab.common.testlib import TestCase, unittest_main
-from logilab.common.graph import get_cycles
+from logilab.common.graph import get_cycles, has_path
 
-class getCycleTestCase(TestCase):
+class getCyclesTC(TestCase):
 
     def test_known0(self):
         self.assertEqual(get_cycles({1:[2], 2:[3], 3:[1]}), [[1, 2, 3]])
@@ -15,5 +15,19 @@ class getCycleTestCase(TestCase):
         self.assertEqual(get_cycles({1:[2], 2:[3], 3:[0], 0:[]}), [])
 
 
+class hasPathTC(TestCase):
+
+    def test_direct_connection(self):
+        self.assertEquals(has_path({'A': ['B'], 'B': ['A']}, 'A', 'B'), ['B'])
+
+    def test_indirect_connection(self):
+        self.assertEquals(has_path({'A': ['B'], 'B': ['A', 'C'], 'C': ['B']}, 'A', 'C'), ['B', 'C'])
+
+    def test_no_connection(self):
+        self.assertEquals(has_path({'A': ['B'], 'B': ['A']}, 'A', 'C'), None)
+
+    def test_cycle(self):
+        self.assertEquals(has_path({'A': ['A']}, 'A', 'B'), None)
+
 if __name__ == "__main__":
     unittest_main()