[Zope3-dev] testrunner layers

[Florent Guillaume]

On 21 Dec 2005, at 16:04, Jim Fulton wrote:
> Florent Guillaume wrote:
>> I didn't find the info I was looking for in the unit tests and  
>> docs  for the testrunner:
>> How are layers defined?
>
> This is definately a hole in the testrunner docs.
>
>> Are they just a class with a setUp and  tearDown classmethod?
>> Is it enough to provide a layer attribute in the layer class?
>
> A layer attribute is not part of the api for layers.
>
>> Is  there
>> a use of a 'base' attribute or is it just the unit tests for  the
>> testrunners that have it (they are full of "# Internal to   
>> samples. Not
>> part of layer API" so it's hard to know).
>
> Layers are objects with setUp and tearDown methods and
> __bases__, __module__, and __name__ attributes.  Classes
> with class methods are a common and convenient
> implementation approach.
>
> In addition, a layer's tearDown method is allowed to raise
> NotImplementedError to indicate that the layer doesn't support
> tear down. This is actually documented in testrunner-layers-ntd.txt.
>
> It is also a requirement that layers must be available for import
> using their __module__ and __name__.
>
> The __bases__ attribute indicates that a layer builds on other layers.
> In that case, the base layers will be setUp before the layer and torn
> down after the layer (assuming that the layer and base layers support
> tear down.)
>
>> How does a test class reference a layer? Just by setting the  
>> layer  attribute to the dotted name of the class? Or to the class  
>> itself?
>
> A test or test suite indicates it's layer through it's layer  
> attribute,
> which must be either the dotted name of a layer or the layer itself.
>
>
>> Along what algorithm does the --layer directive match layers? Is  
>> it  an exact match, or a substring? A prefix? How does the base  
>> come into  play?
>
> A regular expression match is used. This is documented in the
> testrunner-layers.txt file, although that documentation doesn't make
> clear whether a regular expression or substring match is used.
> The options help does say that this is a regular expression.
>
>> Also, what's the intent behind no-tearDown layers?
>
> To support layers that can't be torn down. :)
>
> Most notably, changes made by ZCML can't be torn down.
> See the layer defined in zope.app.functional for an example
> of a ZCML-defined layer.
>
> Contributions to the documentation would be welcome. In
> particular:
>
> - The command line help should provide a pointer to the
>   text files. A lot of people haven't realized that there
>   was extensive documentation for the test runner.
>   (We should also apidoc bookify these files.)
>
> - We need a chapter on writing layers.
>
> - It would be good to clarify, where necessary
>   in the text when regular expressions are used.
>
> I won't have time to do this myself this year.

Thanks.
I'll write some doc when I get the hang of using layers (not this  
year either :)).

Florent

-- 
Florent Guillaume, Nuxeo (Paris, France)   Director of R&D
+33 1 40 33 71 59   http://nuxeo.com   fg at nuxeo.com