From 16d4fce0b203bdaa679ad5b3f1e6b6f46880d5d2 Mon Sep 17 00:00:00 2001
From: James O'Beirne <james.obeirne@gmail.com>
Date: Wed, 9 Dec 2015 09:01:34 -0800
Subject: [PATCH 1/3] Add assert_is_hex_string and assert_is_hash_string to RPC
 test utils.

---
 qa/rpc-tests/test_framework/util.py | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/qa/rpc-tests/test_framework/util.py b/qa/rpc-tests/test_framework/util.py
index 72df3ae685..a0f5b1afde 100644
--- a/qa/rpc-tests/test_framework/util.py
+++ b/qa/rpc-tests/test_framework/util.py
@@ -407,5 +407,22 @@ def assert_raises(exc, fun, *args, **kwds):
     else:
         raise AssertionError("No exception raised")
 
+def assert_is_hex_string(string):
+    try:
+        int(string, 16)
+    except Exception as e:
+        raise AssertionError(
+            "Couldn't interpret %r as hexadecimal; raised: %s" % (string, e))
+
+def assert_is_hash_string(string, length=64):
+    if not isinstance(string, basestring):
+        raise AssertionError("Expected a string, got type %r" % type(string))
+    elif length and len(string) != length:
+        raise AssertionError(
+            "String of length %d expected; got %d" % (length, len(string)))
+    elif not re.match('[abcdef0-9]+$', string):
+        raise AssertionError(
+            "String %r contains invalid characters for a hash." % string)
+
 def satoshi_round(amount):
     return  Decimal(amount).quantize(Decimal('0.00000001'), rounding=ROUND_DOWN)

From 4745636126d9a4f28f701f701be392779815a7bf Mon Sep 17 00:00:00 2001
From: James O'Beirne <james.obeirne@gmail.com>
Date: Wed, 9 Dec 2015 09:02:19 -0800
Subject: [PATCH 2/3] Add RPC documentation for getblockheader[chainwork].

---
 src/rpcblockchain.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/rpcblockchain.cpp b/src/rpcblockchain.cpp
index ee04636ce8..28c2db4501 100644
--- a/src/rpcblockchain.cpp
+++ b/src/rpcblockchain.cpp
@@ -323,7 +323,8 @@ UniValue getblockheader(const UniValue& params, bool fHelp)
             "  \"bits\" : \"1d00ffff\", (string) The bits\n"
             "  \"difficulty\" : x.xxx,  (numeric) The difficulty\n"
             "  \"previousblockhash\" : \"hash\",  (string) The hash of the previous block\n"
-            "  \"nextblockhash\" : \"hash\"       (string) The hash of the next block\n"
+            "  \"nextblockhash\" : \"hash\",      (string) The hash of the next block\n"
+            "  \"chainwork\" : \"0000...1f3\"     (string) Expected number of hashes required to produce the current chain (in hex)\n"
             "}\n"
             "\nResult (for verbose=false):\n"
             "\"data\"             (string) A string that is serialized, hex-encoded data for block 'hash'.\n"

From 135d6ec8cedc83ad800da45080c16d49e9182e80 Mon Sep 17 00:00:00 2001
From: James O'Beirne <james.obeirne@gmail.com>
Date: Wed, 9 Dec 2015 09:02:59 -0800
Subject: [PATCH 3/3] Add RPC tests for getblockheader.

---
 qa/rpc-tests/blockchain.py | 36 +++++++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/qa/rpc-tests/blockchain.py b/qa/rpc-tests/blockchain.py
index b7bfe36285..81deab8900 100755
--- a/qa/rpc-tests/blockchain.py
+++ b/qa/rpc-tests/blockchain.py
@@ -4,19 +4,25 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #
-# Test RPC calls related to blockchain state.
+# Test RPC calls related to blockchain state. Tests correspond to code in
+# rpcblockchain.cpp.
 #
 
 import decimal
 
 from test_framework.test_framework import BitcoinTestFramework
+from test_framework.authproxy import JSONRPCException
 from test_framework.util import (
     initialize_chain,
     assert_equal,
+    assert_raises,
+    assert_is_hex_string,
+    assert_is_hash_string,
     start_nodes,
     connect_nodes_bi,
 )
 
+
 class BlockchainTest(BitcoinTestFramework):
     """
     Test blockchain-related RPC calls:
@@ -36,6 +42,10 @@ class BlockchainTest(BitcoinTestFramework):
         self.sync_all()
 
     def run_test(self):
+        self._test_gettxoutsetinfo()
+        self._test_getblockheader()
+
+    def _test_gettxoutsetinfo(self):
         node = self.nodes[0]
         res = node.gettxoutsetinfo()
 
@@ -47,6 +57,30 @@ class BlockchainTest(BitcoinTestFramework):
         assert_equal(len(res[u'bestblock']), 64)
         assert_equal(len(res[u'hash_serialized']), 64)
 
+    def _test_getblockheader(self):
+        node = self.nodes[0]
+
+        assert_raises(
+            JSONRPCException, lambda: node.getblockheader('nonsense'))
+
+        besthash = node.getbestblockhash()
+        secondbesthash = node.getblockhash(199)
+        header = node.getblockheader(besthash)
+
+        assert_equal(header['hash'], besthash)
+        assert_equal(header['height'], 200)
+        assert_equal(header['confirmations'], 1)
+        assert_equal(header['previousblockhash'], secondbesthash)
+        assert_is_hex_string(header['chainwork'])
+        assert_is_hash_string(header['hash'])
+        assert_is_hash_string(header['previousblockhash'])
+        assert_is_hash_string(header['merkleroot'])
+        assert_is_hash_string(header['bits'], length=None)
+        assert isinstance(header['time'], int)
+        assert isinstance(header['mediantime'], int)
+        assert isinstance(header['nonce'], int)
+        assert isinstance(header['version'], int)
+        assert isinstance(header['difficulty'], decimal.Decimal)
 
 if __name__ == '__main__':
     BlockchainTest().main()