Myujth

Morning folks,

I'm trying to get a few unit tests going in Python to confirm my code is working, but I'm having a real hard time getting a Mock anything to fit into my test cases. I'm new to Python unit testing, so this has been a trying week thus far.

The summary of the program is I'm attempting to do serial control of a commercial monitor I got my hands on and I thought I'd use it as a chance to finally use Python for something rather than just falling back on one of the other languages I know. I've got pyserial going, but before I start shoving a ton of commands out to the TV I'd like to learn the unittest part so I can write for my expected outputs and inputs.

I've tried using a library called dummyserial, but it didn't seem to be recognising the output I was sending. I thought I'd give mock_open a try as I've seen it works like a standard IO as well, but it just isn't picking up on the calls either. Samples of the code involved:

def testSendCmd(self):
 powerCheck = '01:>4r'.format(SharpCodes['POWER'], SharpCodes['CHECK']).encode('utf-8')
 read_text = 'Stuffr'
 mo = mock_open(read_data=read_text)
 mo.in_waiting = len(read_text)
 with patch('__main__.open', mo):
 with open('./serial', 'a+b') as com:
 tv = SharpTV(com=com, TVID=999, tvInput = 'DVI')
 tv.sendCmd(SharpCodes['POWER'], SharpCodes['CHECK'])
 com.write(b'some junk')
 print(mo.mock_calls)
 mo().write.assert_called_with('01:>4r'.format(SharpCodes['POWER'], SharpCodes['CHECK']).encode('utf-8'))

And in the SharpTV class, the function in question:

def sendCmd(self, type, msg):
 sent = self.com.write('01:>4r'.format(type,msg).encode('utf-8'))
 print('01:>4r'.format(type,msg).encode('utf-8'))

Obviously, I'm attempting to control a Sharp TV. I know the commands are correct, that isn't the issue. The issue is just the testing. According to documentation on the mock_open page, calling mo.mock_calls should return some data that a call was made, but I'm getting just an empty set of 's even in spite of the blatantly wrong com.write(b'some junk'), and mo().write.assert_called_with(...) is returning with an assert error because it isn't detecting the write from within sendCmd. What's really bothering me is I can do the examples from the mock_open section in interactive mode and it works as expected.

I'm missing something, I just don't know what. I'd like help getting either dummyserial working, or mock_open.

To answer one part of my question, I figured out the functionality of dummyserial. The following works now:

def testSendCmd(self):
 powerCheck = '01:>4r'.format(SharpCodes['POWER'], SharpCodes['CHECK'])
 com = dummyserial.Serial(
 port='COM1',
 baudrate=9600,
 ds_responses=powerCheck : powerCheck
 )
 tv = SharpTV(com=com, TVID=999, tvInput = 'DVI')
 tv.sendCmd(SharpCodes['POWER'], SharpCodes['CHECK'])
 self.assertEqual(tv.recv(), powerCheck)

Previously I was encoding the dictionary values as utf-8. The dummyserial library decodes whatever you write(...) to it so it's a straight string vs. string comparison. It also encodes whatever you're read()ing as latin1 on the way back out.