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/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):
-        print("Initializing test directory "+tmp_directory)
-        initialize_chain(tmp_directory)
+    def setup_chain(self):
+        print("Initializing test directory "+self.options.tmpdir)
+        initialize_chain(self.options.tmpdir)
 
-    def setup_network(self, tmp_directory):
-        nodes = start_nodes(2, tmp_directory)
-        connect_nodes(nodes[1], 0)
-        sync_blocks(nodes)
-        return nodes
+    def setup_network(self, split = False):
+        self.nodes = start_nodes(4, self.options.tmpdir)
+
+        # Connect the nodes as a "chain".  This allows us
+        # 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)