Improved documentation and testing of ASCWriter.

Author: christiansandberg

can/CAN.py

@@ -233,7 +233,7 @@ class ASCWriter(Listener):
 
     def __init__(self, filename):
         now = datetime.now().strftime("%a %b %m %I:%M:%S %p %Y")
-        self.start = time.time()
+        self.started = time.time()
         self.log_file = open(filename, "w")
         self.log_file.write("date %s\n" % now)
         self.log_file.write("base hex  timestamps absolute\n")
@@ -254,8 +254,8 @@ def on_message_received(self, msg):
         if msg.id_type:
             arb_id = arb_id + "x"
         timestamp = msg.timestamp
-        if timestamp >= self.start:
-            timestamp -= self.start
+        if timestamp >= self.started:
+            timestamp -= self.started
 
         line = self.LOG_STRING.format(time=timestamp,
                                       channel=1,

doc/listeners.rst

@@ -57,7 +57,11 @@ These Listeners simply create csv and sql files with the messages received.
 ASCWriter
 ---------
 
-Logs CAN data to an ASCII log file.
+Logs CAN data to an ASCII log file compatible with other CAN tools such as
+Vector CANalyzer/CANoe and other.
+Since no official specification exists for the format, it has been reverse-
+engineered from existing log files. One description of the format can be found `here
+<http://zone.ni.com/reference/en-XX/help/370859J-01/dlgcanconverter/dlgcanconverter/canconverter_ascii_logfiles/>`_.
 
 .. autoclass:: can.ASCWriter
     :members:

test/listener_test.py

@@ -67,17 +67,16 @@ def testSQLWriterReceives(self):
 
     def testAscListener(self):
         a_listener = can.ASCWriter("test.asc")
-        notifier = can.Notifier(self.bus, [a_listener], 0.1)
         msg = can.Message(extended_id=True,
+                          timestamp=a_listener.started + 0.5,
                           arbitration_id=0xabcdef,
                           data=[1, 2, 3, 4, 5, 6, 7, 8])
-        self.bus.send(msg)
-        sleep(0.5)
+        a_listener(msg)
         msg = can.Message(extended_id=False,
+                          timestamp=a_listener.started + 1,
                           arbitration_id=0x123,
                           data=[0xff, 0xff])
-        self.bus.send(msg)
-        notifier.stop()
+        a_listener(msg)
         a_listener.stop()
         with open("test.asc") as f:
             print("Output from ASCWriter:")