Apply linters on tests/simple_server.py

Apply all 4 linters on tests/simple_server.py, so we can lint it in the
future and not rename and exclude it.
As we are going to use part or most of tests/utils.py after we remove
the test files testing the old code, then we would need to keep the
simple_server.py file. It's currently used in tests/updater_ng.py
testing the new updater implementation.

Black and isort changes where automatically made.
The only manual changes are:
- pylint disable once in can_connect
- add type annotations
- simplifications around setting up the handler variable
- function docstrings

Signed-off-by: Martin Vrachev <[email protected]>

Author: MVrachev

tests/simple_server.py

@@ -25,40 +25,42 @@
     http://docs.python.org/library/simplehttpserver.html#module-SimpleHTTPServer
 """
 
-import sys
-import random
 import socketserver
+import sys
 from http.server import SimpleHTTPRequestHandler
+from typing import Type, Union
 
 
 class QuietHTTPRequestHandler(SimpleHTTPRequestHandler):
-  """A SimpleHTTPRequestHandler that does not write incoming requests to
-  stderr. """
-  def log_request(self, code='-', size='-'):
-    pass
+    """A SimpleHTTPRequestHandler that does not write incoming requests to
+    stderr."""
+
+    def log_request(
+        self, code: Union[int, str] = "-", size: Union[int, str] = "-"
+    ) -> None:
+        pass
+
 
 # NOTE: On Windows/Python2 tests that use this simple_server.py in a
 # subprocesses hang after a certain amount of requests (~68), if a PIPE is
 # passed as Popen's stderr argument. This problem doesn't emerge if
 # we silence the HTTP messages.
 # If you decide to receive the HTTP messages, then this bug
 # could reappear.
-use_quiet_http_request_handler = True
 
-if len(sys.argv) > 2:
-  use_quiet_http_request_handler = sys.argv[2]
+# pylint: disable=invalid-name
+handler: Type[
+    Union[SimpleHTTPRequestHandler, QuietHTTPRequestHandler]
+] = QuietHTTPRequestHandler
 
-if use_quiet_http_request_handler:
-  handler = QuietHTTPRequestHandler
-else:
-  handler = SimpleHTTPRequestHandler
+if len(sys.argv) > 2:
+    handler = SimpleHTTPRequestHandler
 
 # Allow re-use so you can re-run tests as often as you want even if the
 # tests re-use ports. Otherwise TCP TIME-WAIT prevents reuse for ~1 minute
 socketserver.TCPServer.allow_reuse_address = True
 
-httpd = socketserver.TCPServer(('localhost', 0), handler)
-port_message = 'bind succeeded, server port is: ' \
-    + str(httpd.server_address[1])
+httpd = socketserver.TCPServer(("localhost", 0), handler)
+port_message = "bind succeeded, server port is: " + str(httpd.server_address[1])
 print(port_message)
 httpd.serve_forever()