Some style fixing, and added a test script to test for the major style violations.

PrinterConnection.py

@@ -150,7 +150,6 @@ class PrinterConnection(SignalEmitter):
         self._firmware_file_name = file_name
         self._update_firmware_thread.start()
 
-    
     ##  Private connect function run by thread. Can be started by calling connect.
     def _connect(self): 
         self._is_connecting = True
@@ -378,6 +377,7 @@ class PrinterConnection(SignalEmitter):
                         self.sendCommand("M105 T%d" % self._temperature_requested_extruder_index)
                     else:
                         self.sendCommand("M105")
+
     ##  Send next Gcode in the gcode list            
     def _sendNextGcodeLine(self):
         if self._gcode_position >= len(self._gcode):

USBPrinterManager.py

@@ -19,6 +19,7 @@ from UM.i18n import i18nCatalog
 
 i18n_catalog = i18nCatalog('plugins')
 
+
 class USBPrinterManager(QObject, SignalEmitter, Extension):
     def __init__(self, parent = None):
         super().__init__(parent)
@@ -55,7 +56,6 @@ class USBPrinterManager(QObject, SignalEmitter, Extension):
             self._control_view.setSource(QUrl("plugins/USBPrinting/ControlWindow.qml"))
             self._control_view.show()
 
-    
     processingProgress = pyqtSignal(float, arguments = ['amount'])
     @pyqtProperty(float, notify=processingProgress)
     def progress(self):
@@ -268,7 +268,7 @@ class USBPrinterManager(QObject, SignalEmitter, Extension):
                 i=0
                 while True:
                     values = winreg.EnumValue(key, i)
-                    if not base_list or 'USBSER' in values[0]:
+                    if 'USBSER' in values[0]:
                         base_list += [values[1]]
                     i+=1
             except:
@@ -276,7 +276,7 @@ class USBPrinterManager(QObject, SignalEmitter, Extension):
         
         if base_list:
             base_list = base_list + glob.glob('/dev/ttyUSB*') + glob.glob('/dev/ttyACM*') + glob.glob("/dev/cu.usb*")
-            base_list = filter(lambda s: not 'Bluetooth' in s, base_list) #Filter because mac sometimes puts them in the list
+            base_list = filter(lambda s: 'Bluetooth' not in s, base_list) #Filter because mac sometimes puts them in the list
             #prev = profile.getMachineSetting('serial_port_auto')
             #if prev in base_list:
             #    base_list.remove(prev)

avr_isp/ispBase.py

@@ -57,8 +57,10 @@ class IspBase():
         """
         raise IspError("Called undefined verifyFlash")
 
+
 class IspError(BaseException):
     def __init__(self, value):
         self.value = value
+
     def __str__(self):
         return repr(self.value)

avr_isp/stk500v2.py

@@ -3,7 +3,10 @@ STK500v2 protocol implementation for programming AVR chips.
 The STK500v2 protocol is used by the ArduinoMega2560 and a few other Arduino platforms to load firmware.
 This is a python 3 conversion of the code created by David Braam for the Cura project.
 """
-import os, struct, sys, time
+import os
+import struct
+import sys
+import time
 
 from serial import Serial
 from serial import SerialException
@@ -11,6 +14,7 @@ from serial import SerialTimeoutException
 
 from . import ispBase, intelHex
 
+
 class Stk500v2(ispBase.IspBase):
     def __init__(self):
         self.serial = None