diff --git a/src/tests/testStatebag.py b/src/tests/testStatebag.py
new file mode 100644
--- /dev/null
+++ b/src/tests/testStatebag.py
@@ -0,0 +1,74 @@
+import os.path
+from unittest import TestCase
+
+import config as cfg
+from util import BLACK as B,WHITE as W,EMPTY as _
+from go.engine import SpecGo,Engine
+import go.engine
+from statebag import BoardState,StateBag
+from .util import simpleLoadSgf,listStates
+
+
+class TestBoardState(TestCase):
+	def testBasic(self):
+		s1=BoardState([
+			[_,_,_],
+			[_,_,_],
+			[_,_,_]
+		])
+		s2=BoardState([
+			[_,_,_],
+			[_,B,_],
+			[_,_,_]
+		])
+		g=SpecGo(3)
+		go.engine.eng=Engine(g)
+
+		s2.tryConnect(s1)
+		self.assertIs(s2.getPrev(), s1)
+		self.assertEqual(s2.getWeight(), 1)
+
+	def test2ply(self):
+		s1=BoardState([
+			[_,_,_],
+			[_,_,_],
+			[_,_,_]
+		])
+		s2=BoardState([
+			[_,_,_],
+			[_,B,_],
+			[_,_,_]
+		])
+		s3=BoardState([
+			[_,W,_],
+			[_,B,B],
+			[_,_,_]
+		])
+		g=SpecGo(3)
+		go.engine.eng=Engine(g)
+
+		s2.tryConnect(s1)
+		s3.tryConnect(s2)
+		self.assertIs(s3.getPrev(), s2)
+		self.assertEqual(s3.getWeight(), 1)
+
+
+class TestStateBag(TestCase):
+	def testReal(self):
+		go.engine.eng=Engine()
+		files=["O-Takao-20110106.sgf","Sakai-Iyama-20110110.sgf"]
+
+		for f in files:
+			moves=simpleLoadSgf(os.path.join(cfg.srcDir,"tests/data",f))
+			states=listStates(moves)
+
+			for k in range(1,3):
+				bag=StateBag()
+				i=0
+				for s_ in states:
+					i+=1
+					if i%(2*k-1)>=k: # keep k, skip k-1
+						continue
+					s=bag.pushState(s_)
+					if len(bag._states)>1:
+						self.assertIs(s.getPrev(), bag._states[-2])