Fix help, add RPC tests for getblockheader

- Add assert_is_hex_string and assert_is_hash_string to RPC test utils.
- Add RPC documentation for getblockheader[chainwork].
- Add RPC tests for getblockheader.

Github-Pull: #7194
Rebased-From: 16d4fce0b203bdaa679ad5b3f1e6b6f46880d5d2 4745636126d9a4f28f701f701be392779815a7bf 135d6ec8cedc83ad800da45080c16d49e9182e80

2 files changed, 52 insertions, 1 deletions

diff --git a/qa/rpc-tests/blockchain.py b/qa/rpc-tests/blockchain.py
index eccb506e57..daf6fb57a1 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.
 #
 
 from decimal 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()
diff --git a/qa/rpc-tests/test_framework/util.py b/qa/rpc-tests/test_framework/util.py
index 15fd50363e..d8bb63dbbb 100644
--- a/qa/rpc-tests/test_framework/util.py
+++ b/qa/rpc-tests/test_framework/util.py
@@ -407,6 +407,23 @@ 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)