Merge pull request petertodd#103

0f370eb expose uint256_to_str (pstratem)
a782b77 unittests for uint256 serialization (pstratem)
69d81db Bugfix for uint256_to_str (pstratem)

Author: petertodd

bitcoin/core/serialize.py

@@ -344,14 +344,13 @@ def compact_from_uint256(v):
 def uint256_to_str(u):
     r = b""
     for i in range(8):
-        r += struct.pack('<I', u >> (i * 32) & 0xffff)
+        r += struct.pack('<I', u >> (i * 32) & 0xffffffff)
     return r
 
 def uint256_to_shortstr(u):
     s = "%064x" % (u,)
     return s[:16]
 
-
 __all__ = (
         'MAX_SIZE',
         'Hash',
@@ -372,5 +371,6 @@ def uint256_to_shortstr(u):
         'uint256_from_str',
         'uint256_from_compact',
         'compact_from_uint256',
+        'uint256_to_str',
         'uint256_to_shortstr',
 )

bitcoin/tests/test_serialize.py

@@ -11,7 +11,7 @@
 
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-import unittest
+import unittest, random
 
 from binascii import unhexlify
 
@@ -133,3 +133,14 @@ def test_from_uint256(self):
         self.assertEqual(compact_from_uint256(0x12345600), 0x04123456)
         self.assertEqual(compact_from_uint256(0x92340000), 0x05009234)
         self.assertEqual(compact_from_uint256(0x1234560000000000000000000000000000000000000000000000000000000000), 0x20123456)
+
+class Test_Uint256_Serialize(unittest.TestCase):
+    def test_fixed(self):
+        values = []
+        values.append(0)
+        values.append(0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff)
+        for x in range(100):
+            values.append(random.getrandbits(256))
+        for n in values:
+            assert(uint256_from_str(uint256_to_str(n)) == n)
+