Create virtual socket fixture (socket mocking).

test/conftest.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
-import pytest, os, sys, io
+import pytest, os, sys, io, socket
 
 
 if sys.version_info[0] == 2:
@@ -33,3 +33,80 @@ class _OutputSpy(list):
 @pytest.fixture(scope='module')
 def output_spy():
 	return _OutputSpy()
+
+
+class _VirtualSocket(object):
+	def __init__(self):
+		self.sock_address = ('127.0.0.1', 0)
+		self.peer_address = None
+		self._connected = False
+		self.timeout = -1.0
+		self.rdata = []
+		self.sdata = []
+		self.errors = {}
+	
+	def _check_err(self, method):
+		method_error = self.errors.get(method)
+		if method_error:
+			raise method_error
+	
+	def _connect(self, address):
+		self.peer_address = address
+		self._connected = True
+		self._check_err('connect')
+		return self
+	
+	def settimeout(self, timeout):
+		self.timeout = timeout
+	
+	def gettimeout(self):
+		return self.timeout
+	
+	def getpeername(self):
+		if self.peer_address is None or not self._connected:
+			raise socket.error(57, 'Socket is not connected')
+		return self.peer_address
+	
+	def getsockname(self):
+		return self.sock_address
+	
+	def bind(self, address):
+		self.sock_address = address
+	
+	def listen(self, backlog):
+		pass
+	
+	def accept(self):
+		conn = _VirtualSocket()
+		conn.sock_address = self.sock_address
+		conn.peer_address = ('127.0.0.1', 0)
+		conn._connected = True
+		return conn, conn.peer_address
+	
+	def recv(self, bufsize, flags=0):
+		if not self._connected:
+			raise socket.error(54, 'Connection reset by peer')
+		if not len(self.rdata) > 0:
+			return b''
+		data = self.rdata.pop(0)
+		if isinstance(data, Exception):
+			raise data
+		return data
+	
+	def send(self, data):
+		if self.peer_address is None or not self._connected:
+			raise socket.error(32, 'Broken pipe')
+		self._check_err('send')
+		self.sdata.append(data)
+
+
+@pytest.fixture()
+def virtual_socket(monkeypatch):
+	vsocket = _VirtualSocket()
+	def _c(address):
+		return vsocket._connect(address)
+	def _cc(address, timeout=0, source_address=None):
+		return vsocket._connect(address)
+	monkeypatch.setattr(socket, 'create_connection', _cc)
+	monkeypatch.setattr(socket.socket, 'connect', _c)
+	return vsocket