[SciPy-dev] tests, relative import: what's best ?

[Robert Kern]

David Cournapeau wrote:
> Hi,
> 
>     I have a question regarding tests and import in numpy/scipy in 
> general. When implementing tests, the package to be tested has to be 
> imported, and there are two possibilities on how to do it (both are used 
> in scipy). Taking an hypothetical package foo in scipy as an example:
> 
>     1 : using set_package_path /restore_path facilities of 
> numpy.testing, and do a "relative" import
> 
> set_package_path()
> from foo import bar
> restore_path()
> 
> This means that you can test the package foo without building the whole 
> scipy source tree. This is for example used in scipy.linalg tests. It 
> also correspond to DISTUTILS.txt doc in numpy/doc.
> 
>     2 : using set_package_path / restore_path facilities, and do a 
> "absolute" import:
> 
> set_package_path()
> from scipy.foo import bar
> restore_path()
> 
> In this case, I don't understand why set_package_path is used ? And 
> also, this means that you cannot test the subpackage by itself, you need 
> to install the whole scipy tree. This is for example used in 
> scipy.signal tests.
> 
> Are there any advantages to 2 ? If not, would it be a good idea to 
> convert every package to convention 1 ?

If we can, I'd prefer that we simply make build_src/build_ext --inplace work for
numpy and scipy and then remove set_package_path() and restore_path().

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
 that is made terrible by our own mad attempt to interpret it as though it had
 an underlying truth."
  -- Umberto Eco