Carve out the server testing facility as a separate support lib file.

This provides a support library facility for running http servers
under test in a separate thread - something that is necessary because
we need tests to be able to issue requests against them.

Note for the historical record: there was an attempt to make the
executon wrapped inherit from Thread but experience showed that it
was just too difficult to get right when also intending to keep a
reference to an event that must be consulted from the parent - opt
insteda to create an objectthat quacks much like a Thread but creates
one internally at a time of its pleasing.

tests/support/__init__.py

@@ -65,6 +65,7 @@
 from tests.support.assertover import AssertOver
 from tests.support.configsupp import FakeConfiguration
 from tests.support.loggersupp import FakeLogger
+from tests.support.serversupp import make_wrapped_server
 
 
 # Basic global logging configuration for testing

tests/support/serversupp.py

@@ -0,0 +1,80 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+#
+# --- BEGIN_HEADER ---
+#
+# Copyright (C) 2003-2024  The MiG Project by the Science HPC Center at UCPH
+#
+# This file is part of MiG.
+#
+# MiG is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# MiG is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#
+# -- END_HEADER ---
+#
+
+"""Configuration related details within the test support library."""
+
+from threading import Thread, Event as ThreadEvent
+
+
+class ServerWithinThreadExecutor:
+    """Execute a server within a thread ensuring we are able to
+    block until it is ready to recieve test requests.
+
+    The only requirements on being able to do so are the server
+    supporting an on_start callback which is to be called when
+    the server is ready to handle requests."""
+
+    def __init__(self, ServerClass, *args, **kwargs):
+        self._serverclass = ServerClass
+        self._arguments = (args, kwargs)
+        self._started = ThreadEvent()
+        self._thread = None
+        self._wrapped = None
+
+    def run(self):
+        server_args, server_kwargs = self._arguments
+
+        server_kwargs['on_start'] = lambda _: self._started.set()
+
+        self._wrapped = self._serverclass(*server_args, **server_kwargs)
+
+        try:
+            self._wrapped.serve_forever()
+        except Exception as e:
+            pass
+
+    def start(self):
+        self._thread = Thread(target=self.run)
+        self._thread.start()
+
+    def start_wait_until_ready(self):
+        self.start()
+        self._started.wait()
+        return self
+
+    def stop(self):
+        self.stop_server()
+        self._wrapped = None
+        self._thread.join()
+        self._thread = None
+
+    def stop_server(self):
+        self._wrapped.shutdown()
+        self._wrapped.server_close()
+
+
+def make_wrapped_server(ServerClass, *args, **kwargs):
+    return ServerWithinThreadExecutor(ServerClass, *args, **kwargs)