Accept unit classes in motor groups (#480)

docs/motors.rst

@@ -14,6 +14,7 @@ Most methods which run motors with accept a ``speed`` or ``speed_pct`` argument.
 
 .. autoclass:: SpeedInteger
 .. autoclass:: SpeedPercent
+.. autoclass:: SpeedNativeUnits
 .. autoclass:: SpeedRPS
 .. autoclass:: SpeedRPM
 .. autoclass:: SpeedDPS

ev3dev2/__init__.py

@@ -124,6 +124,9 @@ def matches(attribute, pattern):
                 yield f
 
 
+def library_load_warning_message(library_name, dependent_class):
+    return 'Import warning: Failed to import "{}". {} will be unusable!'.format(library_name, dependent_class)
+
 class DeviceNotFound(Exception):
     pass
 

ev3dev2/button.py

@@ -30,16 +30,26 @@
 
 import array
 import time
-import evdev
-from . import get_current_platform
+import logging
+from . import get_current_platform, library_load_warning_message
+
+log = logging.getLogger(__name__)
 
 try:
     # This is a linux-specific module.
-    # It is required by the Button() class, but failure to import it may be
+    # It is required by the Button class, but failure to import it may be
     # safely ignored if one just needs to run API tests on Windows.
     import fcntl
 except ImportError:
-    print("WARNING: Failed to import fcntl. Button class will be unuseable!")
+    log.warning(library_load_warning_message("fcntl", "Button"))
+
+try:
+    # This is a linux-specific module.
+    # It is required by the Button class, but failure to import it may be
+    # safely ignored if one just needs to run API tests on Windows.
+    import evdev
+except ImportError:
+    log.warning(library_load_warning_message("evdev", "Button"))
 
 
 # Import the button filenames, this is platform specific

ev3dev2/display.py

@@ -31,18 +31,21 @@
 import os
 import mmap
 import ctypes
+import logging
 from PIL import Image, ImageDraw
 from . import fonts
-from . import get_current_platform
+from . import get_current_platform, library_load_warning_message
 from struct import pack
 
+log = logging.getLogger(__name__)
+
 try:
     # This is a linux-specific module.
     # It is required by the Display class, but failure to import it may be
     # safely ignored if one just needs to run API tests on Windows.
     import fcntl
 except ImportError:
-    print("WARNING: Failed to import fcntl. Display class will be unusable!")
+    log.warning(library_load_warning_message("fcntl", "Display"))
 
 class FbMem(object):