Add unittests that verify documented behavior of public methods in Transport

class.

These methods can be overridden.  The tests verify that the overridden
methods are called, and that changes to the connection have a visible
effect on the request.

Lib/test/test_xmlrpc.py

@@ -9,6 +9,7 @@ import threading
 import mimetools
 import httplib
 import socket
+import StringIO
 import os
 from test import test_support
 
@@ -639,9 +640,93 @@ class CGIHandlerTestCase(unittest.TestCase):
         os.remove("xmldata.txt")
         os.remove(test_support.TESTFN)
 
+class FakeSocket:
+
+    def __init__(self):
+        self.data = StringIO.StringIO()
+
+    def send(self, buf):
+        self.data.write(buf)
+        return len(buf)
+
+    def sendall(self, buf):
+        self.data.write(buf)
+
+    def getvalue(self):
+        return self.data.getvalue()
+
+    def makefile(self, x, y):
+        raise RuntimeError
+
+class FakeTransport(xmlrpclib.Transport):
+    """A Transport instance that records instead of sending a request.
+
+    This class replaces the actual socket used by httplib with a
+    FakeSocket object that records the request.  It doesn't provide a
+    response.
+    """
+
+    def make_connection(self, host):
+        conn = xmlrpclib.Transport.make_connection(self, host)
+        conn._conn.sock = self.fake_socket = FakeSocket()
+        return conn
+
+class TransportSubclassTestCase(unittest.TestCase):
+
+    def issue_request(self, transport_class):
+        """Return an HTTP request made via transport_class."""
+        transport = transport_class()
+        proxy = xmlrpclib.ServerProxy("http://example.com/",
+                                      transport=transport)
+        try:
+            proxy.pow(6, 8)
+        except RuntimeError:
+            return transport.fake_socket.getvalue()
+        return None
+
+    def test_custom_user_agent(self):
+        class TestTransport(FakeTransport):
+
+            def send_user_agent(self, conn):
+                xmlrpclib.Transport.send_user_agent(self, conn)
+                conn.putheader("X-Test", "test_custom_user_agent")
+
+        req = self.issue_request(TestTransport)
+        self.assert_("X-Test: test_custom_user_agent\r\n" in req)
+
+    def test_send_host(self):
+        class TestTransport(FakeTransport):
+
+            def send_host(self, conn, host):
+                xmlrpclib.Transport.send_host(self, conn, host)
+                conn.putheader("X-Test", "test_send_host")
+
+        req = self.issue_request(TestTransport)
+        self.assert_("X-Test: test_send_host\r\n" in req)
+
+    def test_send_request(self):
+        class TestTransport(FakeTransport):
+
+            def send_request(self, conn, url, body):
+                xmlrpclib.Transport.send_request(self, conn, url, body)
+                conn.putheader("X-Test", "test_send_request")
+
+        req = self.issue_request(TestTransport)
+        self.assert_("X-Test: test_send_request\r\n" in req)
+
+    def test_send_content(self):
+        class TestTransport(FakeTransport):
+
+            def send_content(self, conn, body):
+                conn.putheader("X-Test", "test_send_content")
+                xmlrpclib.Transport.send_content(self, conn, body)
+
+        req = self.issue_request(TestTransport)
+        self.assert_("X-Test: test_send_content\r\n" in req)
+
 def test_main():
     xmlrpc_tests = [XMLRPCTestCase, HelperTestCase, DateTimeTestCase,
-         BinaryTestCase, FaultTestCase]
+         BinaryTestCase, FaultTestCase, TransportSubclassTestCase]
 
     # The test cases against a SimpleXMLRPCServer raise a socket error
     # 10035 (WSAEWOULDBLOCK) in the server thread handle_request call when