Added TestWrapper class.

A BitcoinTestFramework child class which can be imported by an
external user or project. TestWrapper.setup() initiates an underlying
BitcoinTestFramework object with bitcoind subprocesses, rpc interfaces
and test logging. TestWrapper.shutdown() safely tears down the BitcoinTestFramework object.

Author: jachiang

test/functional/test_framework/test_wrapper.py

@@ -0,0 +1,104 @@
+#!/usr/bin/env python3
+# Copyright (c) 2014-2019 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+from test_framework.test_framework import BitcoinTestFramework
+import argparse
+from os.path import abspath, join
+from os import getpid
+
+"""Wrapper Class for BitcoinTestFramework.
+
+Provides the BitcoinTestFramework rpc & daemon process management
+functionality to external python projects.
+
+The TestWrapper class is a singleton class, which ensures that users only ever
+instantiate a single TestWrapper."""
+
+class TestWrapper:
+
+    class __TestWrapper(BitcoinTestFramework):
+
+        def set_test_params(self):
+            # This can be overriden in setup() parameter.
+            self.num_nodes=3
+
+        def run_test(self):
+            pass
+
+        def setup(self,
+            bitcoind=abspath(join(__file__ ,"../../../..") +  "/src/bitcoind"),
+            bitcoincli=None,
+            setup_clean_chain=True,
+            num_nodes=3,
+            network_thread=None,
+            rpc_timeout=60,
+            supports_cli=False,
+            bind_to_localhost_only=True,
+            nocleanup=False,
+            noshutdown=False,
+            cachedir=abspath(join(__file__ ,"../../../..") + "/test/cache"),
+            tmpdir=None,
+            loglevel='INFO',
+            trace_rpc=False,
+            port_seed=getpid(),
+            coveragedir=None,
+            configfile=abspath(join(__file__ ,"../../../..") + "/test/config.ini"),
+            pdbonfailure=False,
+            usecli = False,
+            perf = False,
+            randomseed = None):
+
+
+            if self.running:
+                print("TestWrapper is already running!")
+                return
+
+            self.setup_clean_chain = setup_clean_chain
+            self.num_nodes = num_nodes
+            self.network_thread = network_thread
+            self.rpc_timeout = rpc_timeout
+            self.supports_cli = supports_cli
+            self.bind_to_localhost_only = bind_to_localhost_only
+
+            self.options = argparse.Namespace
+            self.options.nocleanup = nocleanup
+            self.options.noshutdown = noshutdown
+            self.options.cachedir = cachedir
+            self.options.tmpdir = tmpdir
+            self.options.loglevel = loglevel
+            self.options.trace_rpc = trace_rpc
+            self.options.port_seed = port_seed
+            self.options.coveragedir = coveragedir
+            self.options.configfile = configfile
+            self.options.pdbonfailure = pdbonfailure
+            self.options.usecli = usecli
+            self.options.perf = perf
+            self.options.randomseed = randomseed
+
+            self.options.bitcoind = bitcoind
+            self.options.bitcoincli = bitcoincli
+
+            super().setup()
+            self.running = True
+
+        def shutdown(self):
+            if not self.running:
+                print("TestWrapper is not running!")
+            else:
+                super().shutdown()
+                self.running = False
+
+    instance = None
+
+    def __new__(cls):
+        if not TestWrapper.instance:
+            TestWrapper.instance = TestWrapper.__TestWrapper()
+            TestWrapper.instance.running = False
+        return TestWrapper.instance
+
+    def __getattr__(self, name):
+        return getattr(self.instance, name)
+
+    def __setattr__(self, name, value):
+        return setattr(self.instance, name, value)