[Qgis-developer] How to debug and unit test Python plugins outside QGIS (e.g. in Ecplise IDE + PyDev)

[Andreas Neumann]

 Couldn't this be a GSoC idea?

 Creating a developer-friendly Development environment for Python 
 Developers? With a nice debugging solution, code completion, possibility 
 to do unit tests, integration with the plugin repository, etc.?

 I would guess a lot of devs would gain productivity through such 
 improved developer tools and a student could learn quite a bit in 
 putting these together.

 Andreas

 On Thu, 3 Mar 2011 08:38:36 +0100, Stefan Keller wrote:
> Many thanks also for the hint to standalone apps.!
> I still hope there is a solution to unit test QGIS plugins.
> This would make QGIS programmers even more happy :->
>
> Yours, S.
>
>
> 2011/3/3 Alex Mandel <tech_dev at wildintellect.com>:
>> It might be possible, I'm not super familiar with units tests yet.
>> The big issue I see is that most plugins rely on the main QGIS app
>> providing data to the plugin or interacting with the plugin. If you 
>> can
>> design the test to provide what the unit test needs then it should 
>> be
>> doable. After all you can build standalone python apps with the QGIS 
>> api.
>>
>> Thanks,
>> Alex
>>
>> On 03/02/2011 10:13 PM, Stefan Keller wrote:
>>> Hi Alex,
>>>
>>> Many thanks for your reply. I'll try this.
>>>
>>> But: So you say implicitly that its impossible to run unit tests
>>> (PyUnit) on QGIS plugins?
>>> I still hope there is a way to make PyGt4 module interface 
>>> accessible
>>> outside QGIS. At runtime its there, so it should be somehow 
>>> possible
>>> either by "Forced builtin libs" or by extracting the information by
>>> hand with dummy stubs...?
>>>
>>> Yours, S.
>>>
>>> 2011/3/3 Alex Mandel <tech_dev at wildintellect.com>:
>>>> On 03/02/2011 03:57 PM, Stefan Keller wrote:
>>>>> Hi,
>>>>>
>>>>> I'm new to writing Python plugins for QGIS and I like to debug 
>>>>> and
>>>>> unit test theses outside QGIS runtime but don't see any 
>>>>> instructions
>>>>> on how to do this.
>>>>>
>>>>> Of course, the ultimate test of any plugin is to run it inside 
>>>>> QGIS.
>>>>> But I'd like do that outside QGIS for example in Eclipse IDE (+ 
>>>>> PyDev)
>>>>> in order to get code-completion, to debug it and to write unit 
>>>>> tests
>>>>> on it.
>>>>>
>>>>> The problem is that one gets "ImportError: No module named ..." 
>>>>> with
>>>>> mostly PyQt4/qgis modules which (of course) cannot be imported.
>>>>>
>>>>> This post mentions "Forced builtin libs" and reports a similar
>>>>> problem: 
>>>>> http://www.osgeo.org/pipermail/qgis-developer/2010-February/009182.html
>>>>> ... and this PyDev documentation explains "Forced builtin libs" 
>>>>> and
>>>>> "Predefined completions":
>>>>> http://pydev.org/manual_101_interpreter.html#id1
>>>>>
>>>>> I can't imagine that I'm the first trying to debug and unit test
>>>>> Python plugins for QGIS.
>>>>>
>>>>> Can anybody give me a hand on this?
>>>>>
>>>>> Yours, S.
>>>>
>>>> I've been meaning to write this up for some time. The only way 
>>>> I've
>>>> found to Debug a QGIS plugin is using a debugger hook in python. 
>>>> While I
>>>> have only tested this method with SPE's Winpdb (No Win does not 
>>>> stand
>>>> for MS Windows - SPE is python cross platform) debugger it 
>>>> theoretically
>>>> should be possible with other tools if they support the same kind 
>>>> of
>>>> debugging method.
>>>>
>>>> Basically I insert something like:
>>>> import rpdb2; rpdb2.start_embedded_debugger("testing")
>>>>
>>>> just below the main part of my plugin:
>>>> class MetaEditPlugin:
>>>>    def __init__(self,iface):
>>>>        #Only turn on to use winpdb debugger
>>>>        import rpdb2; rpdb2.start_embedded_debugger("testing")
>>>>
>>>> Then the procedure is to start QGIS, Launch the plugin, switch to 
>>>> SPE's
>>>> winpdb, then do File attach, put in the same password "testing".
>>>> It will then show you the running apps you can connect to, once 
>>>> you
>>>> select and connect the plugin will continue to run.
>>>> At this point you can set breakpoints and catch errors. If/When it 
>>>> stops
>>>> at such a point you can interact with the app in a way similar to
>>>> Python's pdb sending eval and exec snippets, and inpecting all 
>>>> your
>>>> variables in the list.
>>>>
>>>> Make sure to comment out that line for production use otherwise 
>>>> your
>>>> plugin will always stall and wait for the debug to connect.
>>>>
>>>> Basically I think this falls under the term "Remote Debugging" if 
>>>> you
>>>> want to try and find ways to do it with other apps.
>>>>
>>>> I'm not sure there is any other practical method as most plugins 
>>>> rely on
>>>> the QGIS built in stuff to be in an active session, so I wouldn't 
>>>> waste
>>>> too much time trying to do it without QGIS running at all.
>>>>
>>>> Enjoy,
>>>> Alex
>>>> _______________________________________________
>>>> Qgis-developer mailing list
>>>> Qgis-developer at lists.osgeo.org
>>>> http://lists.osgeo.org/mailman/listinfo/qgis-developer
>>>>
>>
>> _______________________________________________
>> Qgis-developer mailing list
>> Qgis-developer at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/qgis-developer
>>
> _______________________________________________
> Qgis-developer mailing list
> Qgis-developer at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/qgis-developer

-- 
 --
 Andreas Neumann
 Böschacherstrasse 10A
 8624 Grüt (Gossau ZH)
 Switzerland