Initial python3 changes

Mostly just updating libraries, removing string encoding/decoding,
fixing some edge cases. No new functionality was added in this
commit.

lib/cheroot/test/test_dispatch.py

@@ -0,0 +1,55 @@
+"""Tests for the HTTP server."""
+# -*- coding: utf-8 -*-
+# vim: set fileencoding=utf-8 :
+
+from __future__ import absolute_import, division, print_function
+
+from cheroot.wsgi import PathInfoDispatcher
+
+
+def wsgi_invoke(app, environ):
+    """Serve 1 request from a WSGI application."""
+    response = {}
+
+    def start_response(status, headers):
+        response.update({
+            'status': status,
+            'headers': headers,
+        })
+
+    response['body'] = b''.join(
+        app(environ, start_response),
+    )
+
+    return response
+
+
+def test_dispatch_no_script_name():
+    """Dispatch despite lack of ``SCRIPT_NAME`` in environ."""
+    # Bare bones WSGI hello world app (from PEP 333).
+    def app(environ, start_response):
+        start_response(
+            '200 OK', [
+                ('Content-Type', 'text/plain; charset=utf-8'),
+            ],
+        )
+        return [u'Hello, world!'.encode('utf-8')]
+
+    # Build a dispatch table.
+    d = PathInfoDispatcher([
+        ('/', app),
+    ])
+
+    # Dispatch a request without `SCRIPT_NAME`.
+    response = wsgi_invoke(
+        d, {
+            'PATH_INFO': '/foo',
+        },
+    )
+    assert response == {
+        'status': '200 OK',
+        'headers': [
+            ('Content-Type', 'text/plain; charset=utf-8'),
+        ],
+        'body': b'Hello, world!',
+    }