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

[Stefan Keller]

I still hope this should be an issue to be solved within reasonable
time given Eclipse as IDE.
However, yes, it could be that this turns out to be a larger endeavour.
I can imagine that one solution could be that Python stubs have to be
generated out of PyGt4/QGIS libs?

Yours, S.

2011/3/3 Andreas Neumann <a.neumann at carto.net>:
> 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
>>>>> _______________________________________________
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>>>>> Qgis-developer at lists.osgeo.org
>>>>> http://lists.osgeo.org/mailman/listinfo/qgis-developer
>>>>>
>>>
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