#!/usr/bin/python
+
 
 # Could be achieved via mocker, but this class is test-framework-agnostic
 class MockSocketObject:
     # Not strictly necessary, but improves performance
     @staticmethod

 #!/usr/bin/python
 
 # Could be achieved via mocker, but this class is test-framework-agnostic
+
 
 # Not strictly necessary, but certainly improves speed and isolation
 # from the host system state (which is irrelevant to this test).
 @staticmethod
 def gethostname():
-    return 'TEST_HOST_NAME'
+    return "TEST_HOST_NAME"
 
 
 @staticmethod
 def gethostbyname(_):
-    return 'TEST_IP_ADDRESS'
+    return "TEST_IP_ADDRESS"

 import sys
 
 import worker.service as service
 
 # listen on all interfaces
-host = ''
+host = ""
 
 
 def main(args):
     if len(args) != 1:
         raise TypeError("Incorrect number of arguments. Please specify a port number")

     port = int(args[0])
     my_socket = service.listen_to(host, port)
     service.handle_requests(my_socket)
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     main(sys.argv[1:])

         my_socket.close()
 
 
 def _process_request(connection_dependency, address):
     request = connection_dependency.recv(1024).decode()
-    print('Connection from {} - received {}'.format(address, request))
+    print("Connection from {} - received {}".format(address, request))
     return _prepare_response()
 
 
 def _prepare_response():
     hostinfo = _get_host_info(socket)
-    response = 'HTTP/1.0 200 OK\n\nHello from {} ({})'.format(*hostinfo)
+    response = "HTTP/1.0 200 OK\n\nHello from {} ({})".format(*hostinfo)
     return response.encode()
 
 
 def _get_ip_address(hostname, get_host_by_name_dependency):
     try:
         return get_host_by_name_dependency(hostname)
     except socket.gaierror as e:
         print("Could not get IP address for {}:\n{}".format(hostname, e))
-        return 'UNKNOWN_IP'
+        return "UNKNOWN_IP"
 
 
 @functools.cache
 def _get_host_info(socket_dependency):
     hostname = socket_dependency.gethostname()

 
 
 @pytest.mark.unit
 def test_main_service_integration(mocker):
     # Arrange
-    mocks = {
-        'listen_to': mocker.DEFAULT,
-        'handle_requests': mocker.DEFAULT
-    }
-    service_mock = mocker.patch.multiple('worker.service', **mocks)
+    mocks = {"listen_to": mocker.DEFAULT, "handle_requests": mocker.DEFAULT}
+    service_mock = mocker.patch.multiple("worker.service", **mocks)
 
     # Act
     _start_sandbox(ANY_PORT, 0)
 
     # Assert

 
 
 class TestPerformance:
     SANDBOX_WARMUP_DURATION = 1 / 1000
     MAX_PERFORMANCE_TEST_DURATION = 2
-    PERFORMANCE_TEST_TIMEOUT_THRESHOLD = SANDBOX_WARMUP_DURATION + MAX_PERFORMANCE_TEST_DURATION
+    PERFORMANCE_TEST_TIMEOUT_THRESHOLD = (
+        SANDBOX_WARMUP_DURATION + MAX_PERFORMANCE_TEST_DURATION
+    )
     PERFORMANCE_REQUEST_COUNT = 5000
 
     hostinfo = None
     response_list = None
 
     @pytest.fixture(scope="class", autouse=True)
     def sandbox_lifecycle_warmstart(self, class_mocker):
         # Arrange
-        spy = class_mocker.spy(service, 'listen_to')
+        spy = class_mocker.spy(service, "listen_to")
         _start_sandbox(ANY_PORT, self.SANDBOX_WARMUP_DURATION)
         hostinfo = spy.spy_return.getsockname()
         self.__class__.hostinfo = hostinfo
         self.__class__.response_list = []
         _fetch_response(hostinfo, "TEST_ANY_REQUEST")

     def test_main_response(self):
         # Act
         response = _fetch_response(self.hostinfo, "TEST_ANY_REQUEST")
 
         # Assert
-        assert "Hello from" in response, "Received incorrect response {}".format(response)
+        assert "Hello from" in response, "Received incorrect response {}".format(
+            response
+        )
 
     @pytest.mark.system
     @pytest.mark.timeout(PERFORMANCE_TEST_TIMEOUT_THRESHOLD)
     def test_performance_main_throughput(self):
         # Act
         start_timestamp = time.monotonic()
         _request_repeatedly(self.hostinfo, self.PERFORMANCE_REQUEST_COUNT)
         elapsed = time.monotonic() - start_timestamp
-        print("Transactions per second = {} (i.e. {} request/response iterations in {} seconds)"
-              .format(self.PERFORMANCE_REQUEST_COUNT / elapsed, self.PERFORMANCE_REQUEST_COUNT, elapsed))
+        print(
+            "Transactions per second = {} (i.e. {} request/response iterations in {} seconds)".format(
+                self.PERFORMANCE_REQUEST_COUNT / elapsed,
+                self.PERFORMANCE_REQUEST_COUNT,
+                elapsed,
+            )
+        )
 
         # Assert
-        assert elapsed < self.MAX_PERFORMANCE_TEST_DURATION, "Execution took {} seconds (max is {} seconds)" \
-            .format(elapsed, self.MAX_PERFORMANCE_TEST_DURATION)
+        assert (
+            elapsed < self.MAX_PERFORMANCE_TEST_DURATION
+        ), "Execution took {} seconds (max is {} seconds)".format(
+            elapsed, self.MAX_PERFORMANCE_TEST_DURATION
+        )
 
     @pytest.mark.system
     @pytest.mark.timeout(PERFORMANCE_TEST_TIMEOUT_THRESHOLD)
     def test_performance_main_success_rate(self):
         # Act
-        _request_repeatedly(self.hostinfo, self.PERFORMANCE_REQUEST_COUNT, self.response_list.append)
+        _request_repeatedly(
+            self.hostinfo, self.PERFORMANCE_REQUEST_COUNT, self.response_list.append
+        )
 
         # Assert
         response_count = len(self.response_list)
-        assert response_count == self.PERFORMANCE_REQUEST_COUNT, "Expected {} responses, but received {}" \
-            .format(self.PERFORMANCE_REQUEST_COUNT, response_count)
+        assert (
+            response_count == self.PERFORMANCE_REQUEST_COUNT
+        ), "Expected {} responses, but received {}".format(
+            self.PERFORMANCE_REQUEST_COUNT, response_count
+        )
 
 
 def _request_repeatedly(hostinfo, request_count, on_response=lambda noop: None):
     for _ in range(request_count):
         response = _fetch_response(hostinfo, "TEST_PERFORMANCE_ANY_REQUEST")

     s.connect(hostinfo)
     return s
 
 
 def _start_sandbox(port, startup_time):
-    threading.Thread(
-        target=sandbox.main,
-        args=[port],
-        daemon=True
-    ).start()
+    threading.Thread(target=sandbox.main, args=[port], daemon=True).start()
     time.sleep(startup_time)

 from . import mock_socket_object
 from . import mock_socket_package
 import worker.service as service
 
 unsupported_platform = {
-    'condition': platform.system() != 'Linux',
-    'reason': "Test only produces meaningful results in a production-like Linux environment"
+    "condition": platform.system() != "Linux",
+    "reason": "Test only produces meaningful results in a production-like Linux environment",
 }
 
 
 @pytest.mark.skipif(**unsupported_platform)
 @pytest.mark.system

 
     # Act
     result = service._get_ip_address("TEST_HOSTNAME", receive_hostname)
 
     # Assert
-    assert result == 'UNKNOWN_IP'
+    assert result == "UNKNOWN_IP"
 
 
 # Tests the implementation instead of the result. Low ROI to create and maintain this :(
 @pytest.mark.integration
 def test_listen_to_port(mocker):
     # Arrange
     socket_object_mock = mock_socket_object.MockSocketObject()
-    socket_method_mock = mocker.patch('socket.socket', return_value=socket_object_mock)
-    bind_method_mock = mocker.patch.object(socket_object_mock, 'bind', return_value=None)
-    listen_method_mock = mocker.patch.object(socket_object_mock, 'listen', return_value=None)
+    socket_method_mock = mocker.patch("socket.socket", return_value=socket_object_mock)
+    bind_method_mock = mocker.patch.object(
+        socket_object_mock, "bind", return_value=None
+    )
+    listen_method_mock = mocker.patch.object(
+        socket_object_mock, "listen", return_value=None
+    )
 
     # Act
     service.listen_to("localhost", 0)
 
     # Assert

 
 
 @pytest.mark.unit
 def test_listen_to_port_returns_object(mocker):
     # Arrange
-    socket_method_mock = mocker.patch('socket.socket')
+    socket_method_mock = mocker.patch("socket.socket")
     socket_object_mock = mock_socket_object.MockSocketObject()
-    mocker.patch.object(socket_object_mock, 'bind', return_value=None)
-    mocker.patch.object(socket_object_mock, 'listen', return_value=None)
+    mocker.patch.object(socket_object_mock, "bind", return_value=None)
+    mocker.patch.object(socket_object_mock, "listen", return_value=None)
     socket_method_mock.return_value = socket_object_mock
 
     # Act
     result_socket = service.listen_to("localhost", 0)
 

 
 
 @pytest.mark.unit
 def test_prepared_response_includes_required_info(mocker):
     # Arrange
-    required_info = ('TEST_IP_ADDRESS', 'TEST_HOST_NAME')
-    mocker.patch('worker.service._get_host_info', return_value=required_info)
+    required_info = ("TEST_IP_ADDRESS", "TEST_HOST_NAME")
+    mocker.patch("worker.service._get_host_info", return_value=required_info)
 
     # Act
     response = service._prepare_response()
 
     # Assert
     contains_required_info = all(x.encode() in response for x in required_info)
-    assert contains_required_info, "Could not find both '{}' and '{}' in the response '{}'"\
-        .format(*required_info, response)
+    assert (
+        contains_required_info
+    ), "Could not find both '{}' and '{}' in the response '{}'".format(
+        *required_info, response
+    )
 
 
 @pytest.mark.unit
 def test_get_hostinfo_returns_tuple():
     # Act