Extend getchaintips RPC test.

Add the capability to simulate network splits to the RPC test framework
and use it to do more extensive testing of 'getchaintips'.

qa/rpc-tests/forknotify.py

@@ -17,31 +17,30 @@ class ForkNotifyTest(BitcoinTestFramework):
 
     alert_filename = None  # Set by setup_network
 
-    def setup_network(self, test_dir):
+    def setup_network(self):
-        nodes = []
+        self.nodes = []
-        self.alert_filename = os.path.join(test_dir, "alert.txt")
+        self.alert_filename = os.path.join(self.options.tmpdir, "alert.txt")
         with open(self.alert_filename, 'w') as f:
             pass  # Just open then close to create zero-length file
-        nodes.append(start_node(0, test_dir,
+        self.nodes.append(start_node(0, self.options.tmpdir,
                             ["-blockversion=2", "-alertnotify=echo %s >> '" + self.alert_filename + "'"]))
         # Node1 mines block.version=211 blocks
-        nodes.append(start_node(1, test_dir,
+        self.nodes.append(start_node(1, self.options.tmpdir,
                                 ["-blockversion=211"]))
-        connect_nodes(nodes[1], 0)
+        connect_nodes(self.nodes[1], 0)
 
-        sync_blocks(nodes)
+        self.is_network_split = False
-        return nodes
+        self.sync_all()
-        
 
-    def run_test(self, nodes):
+    def run_test(self):
         # Mine 51 up-version blocks
-        nodes[1].setgenerate(True, 51)
+        self.nodes[1].setgenerate(True, 51)
-        sync_blocks(nodes)
+        self.sync_all()
         # -alertnotify should trigger on the 51'st,
         # but mine and sync another to give
         # -alertnotify time to write
-        nodes[1].setgenerate(True, 1)
+        self.nodes[1].setgenerate(True, 1)
-        sync_blocks(nodes)
+        self.sync_all()
 
         with open(self.alert_filename, 'r') as f:
             alert_text = f.read()
@@ -50,10 +49,10 @@ class ForkNotifyTest(BitcoinTestFramework):
             raise AssertionError("-alertnotify did not warn of up-version blocks")
 
         # Mine more up-version blocks, should not get more alerts:
-        nodes[1].setgenerate(True, 1)
+        self.nodes[1].setgenerate(True, 1)
-        sync_blocks(nodes)
+        self.sync_all()
-        nodes[1].setgenerate(True, 1)
+        self.nodes[1].setgenerate(True, 1)
-        sync_blocks(nodes)
+        self.sync_all()
 
         with open(self.alert_filename, 'r') as f:
             alert_text2 = f.read()

qa/rpc-tests/getblocktemplate.py

@@ -51,40 +51,40 @@ class GetBlockTemplateTest(BitcoinTestFramework):
     Test longpolling with getblocktemplate.
     '''
 
-    def run_test(self, nodes):
+    def run_test(self):
         print "Warning: this test will take about 70 seconds in the best case. Be patient."
-        nodes[0].setgenerate(True, 10)
+        self.nodes[0].setgenerate(True, 10)
-        templat = nodes[0].getblocktemplate()
+        templat = self.nodes[0].getblocktemplate()
         longpollid = templat['longpollid']
         # longpollid should not change between successive invocations if nothing else happens
-        templat2 = nodes[0].getblocktemplate()
+        templat2 = self.nodes[0].getblocktemplate()
         assert(templat2['longpollid'] == longpollid)
 
         # Test 1: test that the longpolling wait if we do nothing
-        thr = LongpollThread(nodes[0])
+        thr = LongpollThread(self.nodes[0])
         thr.start()
         # check that thread still lives
         thr.join(5)  # wait 5 seconds or until thread exits
         assert(thr.is_alive())
 
         # Test 2: test that longpoll will terminate if another node generates a block
-        nodes[1].setgenerate(True, 1)  # generate a block on another node
+        self.nodes[1].setgenerate(True, 1)  # generate a block on another node
         # check that thread will exit now that new transaction entered mempool
         thr.join(5)  # wait 5 seconds or until thread exits
         assert(not thr.is_alive())
 
         # Test 3: test that longpoll will terminate if we generate a block ourselves
-        thr = LongpollThread(nodes[0])
+        thr = LongpollThread(self.nodes[0])
         thr.start()
-        nodes[0].setgenerate(True, 1)  # generate a block on another node
+        self.nodes[0].setgenerate(True, 1)  # generate a block on another node
         thr.join(5)  # wait 5 seconds or until thread exits
         assert(not thr.is_alive())
 
         # Test 4: test that introducing a new transaction into the mempool will terminate the longpoll
-        thr = LongpollThread(nodes[0])
+        thr = LongpollThread(self.nodes[0])
         thr.start()
         # generate a random transaction and submit it
-        (txid, txhex, fee) = random_transaction(nodes, Decimal("1.1"), Decimal("0.0"), Decimal("0.001"), 20)
+        (txid, txhex, fee) = random_transaction(self.nodes, Decimal("1.1"), Decimal("0.0"), Decimal("0.001"), 20)
         # after one minute, every 10 seconds the mempool is probed, so in 80 seconds it should have returned
         thr.join(60 + 20)
         assert(not thr.is_alive())

qa/rpc-tests/getchaintips.py

@@ -3,22 +3,52 @@
 # Distributed under the MIT/X11 software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-# Exercise the getchaintips API.
+# Exercise the getchaintips API.  We introduce a network split, work
-
+# on chains of different lengths, and join the network together again.
-# Since the test framework does not generate orphan blocks, we can
+# This gives us two tips, verify that it works.
-# unfortunately not check for them!
 
 from test_framework import BitcoinTestFramework
 from util import assert_equal
 
 class GetChainTipsTest (BitcoinTestFramework):
 
-    def run_test (self, nodes):
+    def run_test (self):
-        res = nodes[0].getchaintips ()
+        BitcoinTestFramework.run_test (self)
-        assert_equal (len (res), 1)
+
-        res = res[0]
+        tips = self.nodes[0].getchaintips ()
-        assert_equal (res['branchlen'], 0)
+        assert_equal (len (tips), 1)
-        assert_equal (res['height'], 200)
+        assert_equal (tips[0]['branchlen'], 0)
+        assert_equal (tips[0]['height'], 200)
+
+        # Split the network and build two chains of different lengths.
+        self.split_network ()
+        self.nodes[0].setgenerate (True, 10);
+        self.nodes[2].setgenerate (True, 20);
+        self.sync_all ()
+
+        tips = self.nodes[1].getchaintips ()
+        assert_equal (len (tips), 1)
+        shortTip = tips[0]
+        assert_equal (shortTip['branchlen'], 0)
+        assert_equal (shortTip['height'], 210)
+
+        tips = self.nodes[3].getchaintips ()
+        assert_equal (len (tips), 1)
+        longTip = tips[0]
+        assert_equal (longTip['branchlen'], 0)
+        assert_equal (longTip['height'], 220)
+
+        # Join the network halves and check that we now have two tips
+        # (at least at the nodes that previously had the short chain).
+        self.join_network ()
+
+        tips = self.nodes[0].getchaintips ()
+        assert_equal (len (tips), 2)
+        assert_equal (tips[0], longTip)
+
+        assert_equal (tips[1]['branchlen'], 10)
+        tips[1]['branchlen'] = 0;
+        assert_equal (tips[1], shortTip)
 
 if __name__ == '__main__':
     GetChainTipsTest ().main ()

qa/rpc-tests/listtransactions.py

@@ -33,62 +33,64 @@ def check_array_result(object_array, to_match, expected):
 
 class ListTransactionsTest(BitcoinTestFramework):
 
-    def run_test(self, nodes):
+    def run_test(self):
         # Simple send, 0 to 1:
-        txid = nodes[0].sendtoaddress(nodes[1].getnewaddress(), 0.1)
+        txid = self.nodes[0].sendtoaddress(self.nodes[1].getnewaddress(), 0.1)
-        sync_mempools(nodes)
+        self.sync_all()
-        check_array_result(nodes[0].listtransactions(),
+        check_array_result(self.nodes[0].listtransactions(),
                            {"txid":txid},
                            {"category":"send","account":"","amount":Decimal("-0.1"),"confirmations":0})
-        check_array_result(nodes[1].listtransactions(),
+        check_array_result(self.nodes[1].listtransactions(),
                            {"txid":txid},
                            {"category":"receive","account":"","amount":Decimal("0.1"),"confirmations":0})
         # mine a block, confirmations should change:
-        nodes[0].setgenerate(True, 1)
+        self.nodes[0].setgenerate(True, 1)
-        sync_blocks(nodes)
+        self.sync_all()
-        check_array_result(nodes[0].listtransactions(),
+        check_array_result(self.nodes[0].listtransactions(),
                            {"txid":txid},
                            {"category":"send","account":"","amount":Decimal("-0.1"),"confirmations":1})
-        check_array_result(nodes[1].listtransactions(),
+        check_array_result(self.nodes[1].listtransactions(),
                            {"txid":txid},
                            {"category":"receive","account":"","amount":Decimal("0.1"),"confirmations":1})
 
         # send-to-self:
-        txid = nodes[0].sendtoaddress(nodes[0].getnewaddress(), 0.2)
+        txid = self.nodes[0].sendtoaddress(self.nodes[0].getnewaddress(), 0.2)
-        check_array_result(nodes[0].listtransactions(),
+        check_array_result(self.nodes[0].listtransactions(),
                            {"txid":txid, "category":"send"},
                            {"amount":Decimal("-0.2")})
-        check_array_result(nodes[0].listtransactions(),
+        check_array_result(self.nodes[0].listtransactions(),
                            {"txid":txid, "category":"receive"},
                            {"amount":Decimal("0.2")})
 
         # sendmany from node1: twice to self, twice to node2:
-        send_to = { nodes[0].getnewaddress() : 0.11, nodes[1].getnewaddress() : 0.22,
+        send_to = { self.nodes[0].getnewaddress() : 0.11,
-                    nodes[0].getaccountaddress("from1") : 0.33, nodes[1].getaccountaddress("toself") : 0.44 }
+                    self.nodes[1].getnewaddress() : 0.22,
-        txid = nodes[1].sendmany("", send_to)
+                    self.nodes[0].getaccountaddress("from1") : 0.33,
-        sync_mempools(nodes)
+                    self.nodes[1].getaccountaddress("toself") : 0.44 }
-        check_array_result(nodes[1].listtransactions(),
+        txid = self.nodes[1].sendmany("", send_to)
+        self.sync_all()
+        check_array_result(self.nodes[1].listtransactions(),
                            {"category":"send","amount":Decimal("-0.11")},
                            {"txid":txid} )
-        check_array_result(nodes[0].listtransactions(),
+        check_array_result(self.nodes[0].listtransactions(),
                            {"category":"receive","amount":Decimal("0.11")},
                            {"txid":txid} )
-        check_array_result(nodes[1].listtransactions(),
+        check_array_result(self.nodes[1].listtransactions(),
                            {"category":"send","amount":Decimal("-0.22")},
                            {"txid":txid} )
-        check_array_result(nodes[1].listtransactions(),
+        check_array_result(self.nodes[1].listtransactions(),
                            {"category":"receive","amount":Decimal("0.22")},
                            {"txid":txid} )
-        check_array_result(nodes[1].listtransactions(),
+        check_array_result(self.nodes[1].listtransactions(),
                            {"category":"send","amount":Decimal("-0.33")},
                            {"txid":txid} )
-        check_array_result(nodes[0].listtransactions(),
+        check_array_result(self.nodes[0].listtransactions(),
                            {"category":"receive","amount":Decimal("0.33")},
                            {"txid":txid, "account" : "from1"} )
-        check_array_result(nodes[1].listtransactions(),
+        check_array_result(self.nodes[1].listtransactions(),
                            {"category":"send","amount":Decimal("-0.44")},
                            {"txid":txid, "account" : ""} )
-        check_array_result(nodes[1].listtransactions(),
+        check_array_result(self.nodes[1].listtransactions(),
                            {"category":"receive","amount":Decimal("0.44")},
                            {"txid":txid, "account" : "toself"} )
 

qa/rpc-tests/receivedby.py

@@ -54,36 +54,36 @@ def check_array_result(object_array, to_match, expected, should_not_find = False
 
 class ReceivedByTest(BitcoinTestFramework):
 
-    def run_test(self, nodes):
+    def run_test(self):
         '''
         listreceivedbyaddress Test
         '''
         # Send from node 0 to 1
-        addr = nodes[1].getnewaddress()
+        addr = self.nodes[1].getnewaddress()
-        txid = nodes[0].sendtoaddress(addr, 0.1)
+        txid = self.nodes[0].sendtoaddress(addr, 0.1)
-        sync_mempools(nodes)
+        self.sync_all()
 
         #Check not listed in listreceivedbyaddress because has 0 confirmations
-        check_array_result(nodes[1].listreceivedbyaddress(),
+        check_array_result(self.nodes[1].listreceivedbyaddress(),
                            {"address":addr},
                            { },
                            True)
         #Bury Tx under 10 block so it will be returned by listreceivedbyaddress
-        nodes[1].setgenerate(True, 10)
+        self.nodes[1].setgenerate(True, 10)
-        sync_blocks(nodes)
+        self.sync_all()
-        check_array_result(nodes[1].listreceivedbyaddress(),
+        check_array_result(self.nodes[1].listreceivedbyaddress(),
                            {"address":addr},
                            {"address":addr, "account":"", "amount":Decimal("0.1"), "confirmations":10, "txids":[txid,]})
         #With min confidence < 10
-        check_array_result(nodes[1].listreceivedbyaddress(5),
+        check_array_result(self.nodes[1].listreceivedbyaddress(5),
                            {"address":addr},
                            {"address":addr, "account":"", "amount":Decimal("0.1"), "confirmations":10, "txids":[txid,]})
         #With min confidence > 10, should not find Tx
-        check_array_result(nodes[1].listreceivedbyaddress(11),{"address":addr},{ },True)
+        check_array_result(self.nodes[1].listreceivedbyaddress(11),{"address":addr},{ },True)
 
         #Empty Tx
-        addr = nodes[1].getnewaddress()
+        addr = self.nodes[1].getnewaddress()
-        check_array_result(nodes[1].listreceivedbyaddress(0,True),
+        check_array_result(self.nodes[1].listreceivedbyaddress(0,True),
                            {"address":addr},
                            {"address":addr, "account":"", "amount":0, "confirmations":0, "txids":[]})
 
@@ -91,24 +91,24 @@ class ReceivedByTest(BitcoinTestFramework):
             getreceivedbyaddress Test
         '''
         # Send from node 0 to 1
-        addr = nodes[1].getnewaddress()
+        addr = self.nodes[1].getnewaddress()
-        txid = nodes[0].sendtoaddress(addr, 0.1)
+        txid = self.nodes[0].sendtoaddress(addr, 0.1)
-        sync_mempools(nodes)
+        self.sync_all()
 
         #Check balance is 0 because of 0 confirmations
-        balance = nodes[1].getreceivedbyaddress(addr)
+        balance = self.nodes[1].getreceivedbyaddress(addr)
         if balance != Decimal("0.0"):
             raise AssertionError("Wrong balance returned by getreceivedbyaddress, %0.2f"%(balance))
 
         #Check balance is 0.1
-        balance = nodes[1].getreceivedbyaddress(addr,0)
+        balance = self.nodes[1].getreceivedbyaddress(addr,0)
         if balance != Decimal("0.1"):
             raise AssertionError("Wrong balance returned by getreceivedbyaddress, %0.2f"%(balance))
 
         #Bury Tx under 10 block so it will be returned by the default getreceivedbyaddress
-        nodes[1].setgenerate(True, 10)
+        self.nodes[1].setgenerate(True, 10)
-        sync_blocks(nodes)
+        self.sync_all()
-        balance = nodes[1].getreceivedbyaddress(addr)
+        balance = self.nodes[1].getreceivedbyaddress(addr)
         if balance != Decimal("0.1"):
             raise AssertionError("Wrong balance returned by getreceivedbyaddress, %0.2f"%(balance))
 
@@ -116,40 +116,40 @@ class ReceivedByTest(BitcoinTestFramework):
             listreceivedbyaccount + getreceivedbyaccount Test
         '''
         #set pre-state
-        addrArr = nodes[1].getnewaddress()
+        addrArr = self.nodes[1].getnewaddress()
-        account = nodes[1].getaccount(addrArr)
+        account = self.nodes[1].getaccount(addrArr)
-        received_by_account_json = get_sub_array_from_array(nodes[1].listreceivedbyaccount(),{"account":account})
+        received_by_account_json = get_sub_array_from_array(self.nodes[1].listreceivedbyaccount(),{"account":account})
         if len(received_by_account_json) == 0:
             raise AssertionError("No accounts found in node")
-        balance_by_account = rec_by_accountArr = nodes[1].getreceivedbyaccount(account)
+        balance_by_account = rec_by_accountArr = self.nodes[1].getreceivedbyaccount(account)
 
-        txid = nodes[0].sendtoaddress(addr, 0.1)
+        txid = self.nodes[0].sendtoaddress(addr, 0.1)
 
         # listreceivedbyaccount should return received_by_account_json because of 0 confirmations
-        check_array_result(nodes[1].listreceivedbyaccount(),
+        check_array_result(self.nodes[1].listreceivedbyaccount(),
                            {"account":account},
                            received_by_account_json)
 
         # getreceivedbyaddress should return same balance because of 0 confirmations
-        balance = nodes[1].getreceivedbyaccount(account)
+        balance = self.nodes[1].getreceivedbyaccount(account)
         if balance != balance_by_account:
             raise AssertionError("Wrong balance returned by getreceivedbyaccount, %0.2f"%(balance))
 
-        nodes[1].setgenerate(True, 10)
+        self.nodes[1].setgenerate(True, 10)
-        sync_blocks(nodes)
+        self.sync_all()
         # listreceivedbyaccount should return updated account balance
-        check_array_result(nodes[1].listreceivedbyaccount(),
+        check_array_result(self.nodes[1].listreceivedbyaccount(),
                            {"account":account},
                            {"account":received_by_account_json["account"], "amount":(received_by_account_json["amount"] + Decimal("0.1"))})
 
         # getreceivedbyaddress should return updates balance
-        balance = nodes[1].getreceivedbyaccount(account)
+        balance = self.nodes[1].getreceivedbyaccount(account)
         if balance != balance_by_account + Decimal("0.1"):
             raise AssertionError("Wrong balance returned by getreceivedbyaccount, %0.2f"%(balance))
 
         #Create a new account named "mynewaccount" that has a 0 balance
-        nodes[1].getaccountaddress("mynewaccount")
+        self.nodes[1].getaccountaddress("mynewaccount")
-        received_by_account_json = get_sub_array_from_array(nodes[1].listreceivedbyaccount(0,True),{"account":"mynewaccount"})
+        received_by_account_json = get_sub_array_from_array(self.nodes[1].listreceivedbyaccount(0,True),{"account":"mynewaccount"})
         if len(received_by_account_json) == 0:
             raise AssertionError("No accounts found in node")
 
@@ -158,7 +158,7 @@ class ReceivedByTest(BitcoinTestFramework):
             raise AssertionError("Wrong balance returned by listreceivedbyaccount, %0.2f"%(received_by_account_json["amount"]))
 
         # Test getreceivedbyaccount for 0 amount accounts
-        balance = nodes[1].getreceivedbyaccount("mynewaccount")
+        balance = self.nodes[1].getreceivedbyaccount("mynewaccount")
         if balance != Decimal("0.0"):
             raise AssertionError("Wrong balance returned by getreceivedbyaccount, %0.2f"%(balance))
 

qa/rpc-tests/smartfees.py

@@ -10,48 +10,48 @@ from util import *
 
 class EstimateFeeTest(BitcoinTestFramework):
 
-    def setup_network(self, test_dir):
+    def setup_network(self):
-        nodes = []
+        self.nodes = []
-        nodes.append(start_node(0, test_dir,
+        self.nodes.append(start_node(0, self.options.tmpdir,
                             ["-debug=mempool", "-debug=estimatefee"]))
         # Node1 mines small-but-not-tiny blocks, and allows free transactions.
         # NOTE: the CreateNewBlock code starts counting block size at 1,000 bytes,
         # so blockmaxsize of 2,000 is really just 1,000 bytes (room enough for
         # 6 or 7 transactions)
-        nodes.append(start_node(1, test_dir,
+        self.nodes.append(start_node(1, self.options.tmpdir,
                                 ["-blockprioritysize=1500", "-blockmaxsize=2000",
                                  "-debug=mempool", "-debug=estimatefee"]))
-        connect_nodes(nodes[1], 0)
+        connect_nodes(self.nodes[1], 0)
 
         # Node2 is a stingy miner, that
         # produces very small blocks (room for only 3 or so transactions)
         node2args = [ "-blockprioritysize=0", "-blockmaxsize=1500",
                       "-debug=mempool", "-debug=estimatefee"]
-        nodes.append(start_node(2, test_dir, node2args))
+        self.nodes.append(start_node(2, self.options.tmpdir, node2args))
-        connect_nodes(nodes[2], 0)
+        connect_nodes(self.nodes[2], 0)
 
-        sync_blocks(nodes)
+        self.is_network_split = False
-        return nodes
+        self.sync_all()
         
 
-    def run_test(self, nodes):
+    def run_test(self):
         # Prime the memory pool with pairs of transactions
         # (high-priority, random fee and zero-priority, random fee)
         min_fee = Decimal("0.001")
         fees_per_kb = [];
         for i in range(12):
-            (txid, txhex, fee) = random_zeropri_transaction(nodes, Decimal("1.1"),
+            (txid, txhex, fee) = random_zeropri_transaction(self.nodes, Decimal("1.1"),
                                                             min_fee, min_fee, 20)
             tx_kbytes = (len(txhex)/2)/1000.0
             fees_per_kb.append(float(fee)/tx_kbytes)
 
         # Mine blocks with node2 until the memory pool clears:
-        count_start = nodes[2].getblockcount()
+        count_start = self.nodes[2].getblockcount()
-        while len(nodes[2].getrawmempool()) > 0:
+        while len(self.nodes[2].getrawmempool()) > 0:
-            nodes[2].setgenerate(True, 1)
+            self.nodes[2].setgenerate(True, 1)
-            sync_blocks(nodes)
+            self.sync_all()
 
-        all_estimates = [ nodes[0].estimatefee(i) for i in range(1,20) ]
+        all_estimates = [ self.nodes[0].estimatefee(i) for i in range(1,20) ]
         print("Fee estimates, super-stingy miner: "+str([str(e) for e in all_estimates]))
 
         # Estimates should be within the bounds of what transactions fees actually were:
@@ -63,25 +63,25 @@ class EstimateFeeTest(BitcoinTestFramework):
         # Generate transactions while mining 30 more blocks, this time with node1:
         for i in range(30):
             for j in range(random.randrange(6-4,6+4)):
-                (txid, txhex, fee) = random_transaction(nodes, Decimal("1.1"),
+                (txid, txhex, fee) = random_transaction(self.nodes, Decimal("1.1"),
                                                         Decimal("0.0"), min_fee, 20)
                 tx_kbytes = (len(txhex)/2)/1000.0
                 fees_per_kb.append(float(fee)/tx_kbytes)
-            nodes[1].setgenerate(True, 1)
+            self.nodes[1].setgenerate(True, 1)
-            sync_blocks(nodes)
+            self.sync_all()
 
-        all_estimates = [ nodes[0].estimatefee(i) for i in range(1,20) ]
+        all_estimates = [ self.nodes[0].estimatefee(i) for i in range(1,20) ]
         print("Fee estimates, more generous miner: "+str([ str(e) for e in all_estimates]))
         for e in filter(lambda x: x >= 0, all_estimates):
             if float(e)+delta < min(fees_per_kb) or float(e)-delta > max(fees_per_kb):
                 raise AssertionError("Estimated fee (%f) out of range (%f,%f)"%(float(e), min_fee_kb, max_fee_kb))
 
         # Finish by mining a normal-sized block:
-        while len(nodes[0].getrawmempool()) > 0:
+        while len(self.nodes[0].getrawmempool()) > 0:
-            nodes[0].setgenerate(True, 1)
+            self.nodes[0].setgenerate(True, 1)
-            sync_blocks(nodes)
+            self.sync_all()
 
-        final_estimates = [ nodes[0].estimatefee(i) for i in range(1,20) ]
+        final_estimates = [ self.nodes[0].estimatefee(i) for i in range(1,20) ]
         print("Final fee estimates: "+str([ str(e) for e in final_estimates]))
 
 

qa/rpc-tests/test_framework.py

@@ -21,22 +21,64 @@ from util import *
 class BitcoinTestFramework(object):
 
     # These may be over-ridden by subclasses:
-    def run_test(self, nodes):
+    def run_test(self):
+        for node in self.nodes:
             assert_equal(node.getblockcount(), 200)
             assert_equal(node.getbalance(), 25*50)
 
     def add_options(self, parser):
         pass
 
-    def setup_chain(self, tmp_directory):
+    def setup_chain(self):
-        print("Initializing test directory "+tmp_directory)
+        print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain(tmp_directory)
+        initialize_chain(self.options.tmpdir)
 
-    def setup_network(self, tmp_directory):
+    def setup_network(self, split = False):
-        nodes = start_nodes(2, tmp_directory)
+        self.nodes = start_nodes(4, self.options.tmpdir)
-        connect_nodes(nodes[1], 0)
+
-        sync_blocks(nodes)
+        # Connect the nodes as a "chain".  This allows us
-        return nodes
+        # to split the network between nodes 1 and 2 to get
+        # two halves that can work on competing chains.
+
+        # If we joined network halves, connect the nodes from the joint
+        # on outward.  This ensures that chains are properly reorganised.
+        if not split:
+            connect_nodes(self.nodes[2], 1)
+            sync_blocks(self.nodes[1:2])
+            sync_mempools(self.nodes[1:2])
+
+        connect_nodes(self.nodes[1], 0)
+        connect_nodes(self.nodes[3], 2)
+        self.is_network_split = split
+        self.sync_all()
+
+    def split_network(self):
+        """
+        Split the network of four nodes into nodes 0/1 and 2/3.
+        """
+        assert not self.is_network_split
+        stop_nodes(self.nodes)
+        wait_bitcoinds()
+        self.setup_network(True)
+
+    def sync_all(self):
+        if self.is_network_split:
+            sync_blocks(self.nodes[:1])
+            sync_blocks(self.nodes[2:])
+            sync_mempools(self.nodes[:1])
+            sync_mempools(self.nodes[2:])
+        else:
+            sync_blocks(self.nodes)
+            sync_mempools(self.nodes)
+
+    def join_network(self):
+        """
+        Join the (previously split) network halves together.
+        """
+        assert self.is_network_split
+        stop_nodes(self.nodes)
+        wait_bitcoinds()
+        self.setup_network(False)
 
     def main(self):
         import optparse
@@ -56,15 +98,14 @@ class BitcoinTestFramework(object):
         check_json_precision()
 
         success = False
-        nodes = []
         try:
             if not os.path.isdir(self.options.tmpdir):
                 os.makedirs(self.options.tmpdir)
-            self.setup_chain(self.options.tmpdir)
+            self.setup_chain()
 
-            nodes = self.setup_network(self.options.tmpdir)
+            self.setup_network()
 
-            self.run_test(nodes)
+            self.run_test()
 
             success = True
 
@@ -80,7 +121,7 @@ class BitcoinTestFramework(object):
 
         if not self.options.nocleanup:
             print("Cleaning up")
-            stop_nodes(nodes)
+            stop_nodes(self.nodes)
             wait_bitcoinds()
             shutil.rmtree(self.options.tmpdir)