diff --git a/src/tests/testEngine.py b/src/tests/testEngine.py
--- a/src/tests/testEngine.py
+++ b/src/tests/testEngine.py
@@ -1,20 +1,51 @@
+import re
+import os.path
+import logging as log
 from unittest import TestCase
 
+import config as cfg
+from util import BLACK as B,WHITE as W,EMPTY as _
+from go.core import Go
 from go.engine import SpecGo,Engine
 from statebag import BoardState
 
 
+_log=log.getLogger(__name__)
+_log.setLevel(log.INFO)
+_log.propagate=False
+formatter=log.Formatter("%(asctime)s %(levelname)s: %(message)s",datefmt="%Y-%m-%d %H:%M:%S")
+handler=log.FileHandler("/tmp/oneeye.log",mode="w")
+handler.setFormatter(formatter)
+_log.addHandler(handler)
+
+
+def simpleLoadSgf(filename):
+	with open(filename) as f:
+		contents=f.read()
+	g=lambda m: tuple(ord(c)-ord('a') for c in reversed(m.group(1)))
+	return [g(m) for m in re.finditer(r"\b[BW]\[([a-z]{2})\]",contents)]
+
+
+def listStates(moves):
+	g=Go()
+	res=[BoardState(g.board)]
+	for m in moves:
+		g.doMove(g.toMove,*m)
+		res.append(BoardState(g.board))
+	return res
+
+
 class TestTransitions(TestCase):
 	def testBasic(self):
 		s1=BoardState([
-			[0,0,0],
-			[0,0,0],
-			[0,0,0]
+			[_,_,_],
+			[_,_,_],
+			[_,_,_]
 		])
 		s2=BoardState([
-			[0,0,0],
-			[0,1,0],
-			[0,0,0]
+			[_,_,_],
+			[_,B,_],
+			[_,_,_]
 		])
 		g=SpecGo(3)
 		eng=Engine(g)
@@ -23,33 +54,83 @@ class TestTransitions(TestCase):
 
 	def testCapture(self):
 		s1=BoardState([
-			[0,-1,0],
-			[-1,1,0],
-			[0,-1,0]
+			[_,W,_],
+			[W,B,_],
+			[_,W,_]
 		])
 		s2=BoardState([
-			[0,-1,0],
-			[-1,0,-1],
-			[0,-1,0]
+			[_,W,_],
+			[W,_,W],
+			[_,W,_]
 		])
 		g=SpecGo(3)
-		g.toMove=-1
+		g.toMove=W
 		eng=Engine(g)
 		eng.load(s1,s2-s1)
-		self.assertEqual(eng.dfs(s2,1),[(-1,1,2)])
+		self.assertEqual(eng.dfs(s2,1),[(W,1,2)])
 
 	def testMulti(self):
 		s1=BoardState([
-			[0,0,0],
-			[0,0,0],
-			[0,0,0]
+			[_,_,_],
+			[_,_,_],
+			[_,_,_]
 		])
 		s2=BoardState([
-			[0,0,0],
-			[0,1,-1],
-			[0,0,0]
+			[_,_,_],
+			[_,B,W],
+			[_,_,_]
 		])
 		g=SpecGo(3)
 		eng=Engine(g)
 		eng.load(s1,s2-s1)
-		self.assertEqual(eng.dfs(s2,2),[(-1,1,2),(1,1,1)])
+		self.assertEqual(eng.dfs(s2,2),[(W,1,2),(B,1,1)])
+
+	def testSnapback(self):
+		s1=BoardState([
+			[B,B,B],
+			[B,_,B],
+			[B,W,B]
+		])
+		s2=BoardState([
+			[_,_,_],
+			[_,_,_],
+			[_,W,_]
+		])
+		g=SpecGo(3)
+		eng=Engine(g)
+		eng.load(s1,s2-s1)
+		self.assertEqual(eng.dfs(s2,2),[(W,2,1),(B,1,1)])
+
+		s1=BoardState([
+			[_,_,_],
+			[W,B,B],
+			[_,W,W]
+		])
+		s2=BoardState([
+			[_,_,_],
+			[W,B,B],
+			[_,W,_]
+		])
+		eng.load(s1,s2-s1)
+		self.assertEqual(eng.dfs(s2,2),[(W,2,1),(B,2,0)])
+
+	def testReal(self):
+		files=["O-Takao-20110106.sgf","Sakai-Iyama-20110110.sgf"]
+		g=SpecGo()
+		eng=Engine(g)
+
+		for f in files:
+			moves=simpleLoadSgf(os.path.join(cfg.srcDir,"tests/data",f))
+			states=listStates(moves)
+
+			for k in range(1,4):
+				toMove=B
+				for (s1,s2) in zip(states,states[k:]):
+					diff=s2-s1
+					eng.load(s1,diff)
+					seq=eng.iterativelyDeepen(s2,toMove)
+					msg="\n"+s1.exportDiff(s2)
+					self.assertIsNotNone(seq,msg)
+					self.assertLessEqual(len(seq),k,msg)
+					if len(seq)!=k: _log.warning("shorter than expected transition sequence:" + msg + "\n" + str(seq))
+					toMove*=-1