[AstroPy] Revert to astropy 1.3 constants (for testing) in astropy 2.0

[Thomas Robitaille]

Hi Duncan,

Just to close the loop on this (and in case anyone finds this thread),
this will be much simpler in the upcoming 3.0 release, as there will
be a context manager to do this:

http://docs.astropy.org/en/latest/api/astropy.constants.set_enabled_constants.html#astropy.constants.set_enabled_constants

Cheers,
Tom


On 10 July 2017 at 15:01, Duncan Macleod <duncan.macleod at ligo.org> wrote:
> Hi Derek,
>
> Unfortunately, I don't want to change the imports in my module, but only in
> the test suite. Essentially I want to mock the constants module back to
> astropy-1.3 values.
>
> In the end I ended up with the following in my test module:
>
> from astropy import __version__ as astropy_version
> if astropy_version >= '2.0':
>     from astropy import constants
>     from astropy.constants import (si, astropyconst13)
>     units.M_sun._represents = units.Unit(astropyconst13.M_sun)
>     constants.M_sun = si.M_sun = astropyconst13.M_sun
>     constants.G = si.G = astropyconst13.G
>     constants.c = si.c = astropyconst13.c
>     constants.pc = si.pc = astropyconst13.pc
>
> to just fix the constants I need without editing the module code that
> actually uses them. This is after the module import, but before any function
> calls. A bit messy, but does the job.
>
>
> D
>
> On 10 July 2017 at 14:56, Derek Homeier
> <derek at astro.physik.uni-goettingen.de> wrote:
>>
>> On 10 Jul 2017, at 2:34 pm, Duncan Macleod <duncan.macleod at ligo.org>
>> wrote:
>> >
>> > Is there a way to tell astropy.constants to use the version 1.3
>> > constants (from astropy.constants.astropyconst13) when using the v2.0
>> > package? i.e. have astropy.constants.M_sun come from iau2012 and not
>> > iau2015?
>> >
>> > I have a bunch of unit tests are now failing because of the relatively
>> > large changes in some constants.*
>> >
>> Depends on how you currently import them, but replacing e.g.
>>
>> from astropy import constants as const
>>
>> with
>>
>> from astropy.constants import astropyconst13 as const
>>
>> should have the desired effect.
>>
>> HTH
>>                                                 Derek
>>
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>
>
>
>
> --
> Duncan Macleod
> duncan.macleod at ligo.org
> Sêr Cymru Cofund Fellow
> School of Physics and Astronomy
> Cardiff University
>
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