diff --git a/src/tests/__init__.py b/src/tests/__init__.py
new file mode 100644
diff --git a/src/tests/test_gf256.py b/src/tests/test_gf256.py
new file mode 100644
--- /dev/null
+++ b/src/tests/test_gf256.py
@@ -0,0 +1,60 @@
+import random
+import unittest
+from unittest import TestCase
+
+from gf256 import _gfmul
+from gf256 import *
+
+
+class TestGF256(TestCase):
+	def test_gfmul(self):
+		self.assertEqual(_gfmul(0,0), 0)
+		self.assertEqual(_gfmul(1,1), 1)
+		self.assertEqual(_gfmul(2,2), 4)
+		self.assertEqual(_gfmul(0,21), 0)
+		self.assertEqual(_gfmul(0x53,0xca), 0x01)
+		self.assertEqual(_gfmul(0xff,0xff), 0x13)
+
+	def testGfmul(self):
+		for a in range(256):
+			for b in range(256):
+				self.assertEqual(_gfmul(a,b), gfmul(a,b))
+
+	def testEvaluate(self):
+		for x in range(256):
+			(a0,a1,a2,a3)=(x,x>>1,x>>2,x>>3)
+			self.assertEqual(evaluate([17],x), 17) # constant polynomial
+			self.assertEqual(evaluate([a0,a1,a2,a3],0), x) # any polynomial at 0
+			self.assertEqual(evaluate([a0,a1,a2,a3],1), a0^a1^a2^a3) # polynomial at 1 == sum of coefficients
+
+	def testGetConstantCoef(self):
+		self.assertEqual(getConstantCoef((1,1),(2,2),(3,3)), 0)
+
+		random.seed(17)
+		randomMatches=0
+		for i in range(10):
+			k=random.randint(2,255)
+
+			# exact
+			res=self.checkCoefsMatch(k,k)
+			self.assertEqual(res[0], res[1])
+
+			# overdetermined
+			res=self.checkCoefsMatch(k,256)
+			self.assertEqual(res[0], res[1])
+
+			# underdetermined => random
+			res=self.checkCoefsMatch(k,k-1)
+			if res[0]==res[1]:
+				randomMatches+=1
+		self.assertLess(randomMatches, 2) # with a chance (255/256)**10=0.96 there should be no match
+
+	def checkCoefsMatch(self,k,m):
+		coefs=[random.randint(0,255) for i in range(k)]
+		points=[(j, evaluate(coefs,j)) for j in range(1,256)]
+		random.shuffle(points)
+		return (getConstantCoef(*points[:m]), coefs[0])
+
+
+if __name__ == '__main__':
+	unittest.main()