Merge pull request #191 from WasabiFan/add-class-dir-check

Fix error when a device class dir doesn't exist

Author: dwalton76

ev3dev/core.py

@@ -57,6 +57,10 @@
 
 # -----------------------------------------------------------------------------
 def list_device_names(class_path, name_pattern, **kwargs):
+
+    if not os.path.isdir(class_path):
+        return
+    
     """
     This is a generator function that lists names of all devices matching the
     provided parameters.

tests/api_tests.py

@@ -9,7 +9,7 @@
 from populate_arena import populate_arena
 from clean_arena    import clean_arena
 
-import ev3dev.ev3 as ev3
+import ev3dev.core as ev3
 
 ev3.Device.DEVICE_ROOT_PATH = os.path.join(FAKE_SYS, 'arena')
 
@@ -36,6 +36,9 @@ def test_device(self):
         d = ev3.Device('lego-sensor', 'sensor*')
         self.assertTrue(d.connected)
 
+        d = ev3.Device('this-does-not-exist')
+        self.assertFalse(d.connected)
+
     def test_medium_motor(self):
         def dummy(self):
             pass