[pypy-svn] r73978 - pypy/branch/blackhole-improvement/pypy/tool/algo

[arigo at codespeak.net]

Author: arigo
Date: Thu Apr 22 16:42:58 2010
New Revision: 73978

Modified:
   pypy/branch/blackhole-improvement/pypy/tool/algo/color.py
Log:
Add asserts.


Modified: pypy/branch/blackhole-improvement/pypy/tool/algo/color.py
==============================================================================
--- pypy/branch/blackhole-improvement/pypy/tool/algo/color.py	(original)
+++ pypy/branch/blackhole-improvement/pypy/tool/algo/color.py	Thu Apr 22 16:42:58 2010
@@ -11,6 +11,7 @@
         self.neighbours[v] = set()
 
     def add_edge(self, v1, v2):
+        assert v1 != v2
         self.neighbours[v1].add(v2)
         self.neighbours[v2].add(v1)
 
@@ -18,6 +19,7 @@
         """Remove vold from the graph, and attach all its edges to vnew."""
         for n in self.neighbours.pop(vold):
             self.neighbours[n].remove(vold)
+            assert vnew != n
             self.neighbours[n].add(vnew)
             self.neighbours[vnew].add(n)
         # we should remove vold from self._all_nodes, but it's too costly