[tests] Introduce TestNode

TestNode is a class responsible for all state related to a bitcoind node
under test. It stores local state, is responsible for tracking the
bitcoind process and delegates unrecognised messages to the RPC
connection.

This commit changes start_nodes and stop_nodes to start and stop the
bitcoind nodes in parallel, making test setup and teardown much faster.

1 files changed, 134 insertions, 0 deletions

diff --git a/test/functional/test_framework/test_node.py b/test/functional/test_framework/test_node.py
new file mode 100755
index 0000000000..66f89d43f4
--- /dev/null
+++ b/test/functional/test_framework/test_node.py
@@ -0,0 +1,134 @@
+#!/usr/bin/env python3
+# Copyright (c) 2017 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+"""Class for bitcoind node under test"""
+
+import errno
+import http.client
+import logging
+import os
+import subprocess
+import time
+
+from .util import (
+    assert_equal,
+    get_rpc_proxy,
+    rpc_url,
+)
+from .authproxy import JSONRPCException
+
+class TestNode():
+    """A class for representing a bitcoind node under test.
+
+    This class contains:
+
+    - state about the node (whether it's running, etc)
+    - a Python subprocess.Popen object representing the running process
+    - an RPC connection to the node
+
+    To make things easier for the test writer, a bit of magic is happening under the covers.
+    Any unrecognised messages will be dispatched to the RPC connection."""
+
+    def __init__(self, i, dirname, extra_args, rpchost, timewait, binary, stderr, mocktime, coverage_dir):
+        self.index = i
+        self.datadir = os.path.join(dirname, "node" + str(i))
+        self.rpchost = rpchost
+        self.rpc_timeout = timewait
+        if binary is None:
+            self.binary = os.getenv("BITCOIND", "bitcoind")
+        else:
+            self.binary = binary
+        self.stderr = stderr
+        self.coverage_dir = coverage_dir
+        # Most callers will just need to add extra args to the standard list below. For those callers that need more flexibity, they can just set the args property directly.
+        self.extra_args = extra_args
+        self.args = [self.binary, "-datadir=" + self.datadir, "-server", "-keypool=1", "-discover=0", "-rest", "-logtimemicros", "-debug", "-debugexclude=libevent", "-debugexclude=leveldb", "-mocktime=" + str(mocktime), "-uacomment=testnode%d" % i]
+
+        self.running = False
+        self.process = None
+        self.rpc_connected = False
+        self.rpc = None
+        self.url = None
+        self.log = logging.getLogger('TestFramework.node%d' % i)
+
+    def __getattr__(self, *args, **kwargs):
+        """Dispatches any unrecognised messages to the RPC connection."""
+        assert self.rpc_connected and self.rpc is not None, "Error: no RPC connection"
+        return self.rpc.__getattr__(*args, **kwargs)
+
+    def start(self):
+        """Start the node."""
+        self.process = subprocess.Popen(self.args + self.extra_args, stderr=self.stderr)
+        self.running = True
+        self.log.debug("bitcoind started, waiting for RPC to come up")
+
+    def wait_for_rpc_connection(self):
+        """Sets up an RPC connection to the bitcoind process. Returns False if unable to connect."""
+
+        # Wait for up to 10 seconds for the RPC server to respond
+        for _ in range(40):
+            assert not self.process.poll(), "bitcoind exited with status %i during initialization" % self.process.returncode
+            try:
+                self.rpc = get_rpc_proxy(rpc_url(self.datadir, self.index, self.rpchost), self.index, coveragedir=self.coverage_dir)
+                self.rpc.getblockcount()
+                # If the call to getblockcount() succeeds then the RPC connection is up
+                self.rpc_connected = True
+                self.url = self.rpc.url
+                self.log.debug("RPC successfully started")
+                return
+            except IOError as e:
+                if e.errno != errno.ECONNREFUSED:  # Port not yet open?
+                    raise  # unknown IO error
+            except JSONRPCException as e:  # Initialization phase
+                if e.error['code'] != -28:  # RPC in warmup?
+                    raise  # unknown JSON RPC exception
+            except ValueError as e:  # cookie file not found and no rpcuser or rpcassword. bitcoind still starting
+                if "No RPC credentials" not in str(e):
+                    raise
+            time.sleep(0.25)
+        raise AssertionError("Unable to connect to bitcoind")
+
+    def get_wallet_rpc(self, wallet_name):
+        assert self.rpc_connected
+        assert self.rpc
+        wallet_path = "wallet/%s" % wallet_name
+        return self.rpc / wallet_path
+
+    def stop_node(self):
+        """Stop the node."""
+        if not self.running:
+            return
+        self.log.debug("Stopping node")
+        try:
+            self.stop()
+        except http.client.CannotSendRequest:
+            self.log.exception("Unable to stop node.")
+
+    def is_node_stopped(self):
+        """Checks whether the node has stopped.
+
+        Returns True if the node has stopped. False otherwise.
+        This method is responsible for freeing resources (self.process)."""
+        if not self.running:
+            return True
+        return_code = self.process.poll()
+        if return_code is not None:
+            # process has stopped. Assert that it didn't return an error code.
+            assert_equal(return_code, 0)
+            self.running = False
+            self.process = None
+            self.log.debug("Node stopped")
+            return True
+        return False
+
+    def node_encrypt_wallet(self, passphrase):
+        """"Encrypts the wallet.
+
+        This causes bitcoind to shutdown, so this method takes
+        care of cleaning up resources."""
+        self.encryptwallet(passphrase)
+        while not self.is_node_stopped():
+            time.sleep(0.1)
+        self.rpc = None
+        self.rpc_connected = False