WCS test fails if sunpy is installed

It looks like simply having SunPy installed is causing the following test to fail:

______________________________________________________________________________________ test_celestial_frame_to_wcs _______________________________________________________________________________________

    def test_celestial_frame_to_wcs():
    
        # Import astropy.coordinates here to avoid circular imports
        from astropy.coordinates import ICRS, ITRS, FK5, FK4, FK4NoETerms, Galactic, BaseCoordinateFrame
    
        class FakeFrame(BaseCoordinateFrame):
            pass
    
        frame = FakeFrame()
        with pytest.raises(ValueError) as exc:
>           celestial_frame_to_wcs(frame)

astropy/wcs/tests/test_utils.py:367: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
astropy/wcs/utils.py:277: in celestial_frame_to_wcs
    wcs = func(frame, projection=projection)
/Users/tom/python/dev/lib/python3.7/site-packages/sunpy/coordinates/wcs_utils.py:65: in solar_frame_to_wcs_mapping
    wcs.wcs.dateobs = frame.obstime.utc.isot
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <FakeFrame Frame>, attr = 'obstime'

    def __getattr__(self, attr):
        """
        Allow access to attributes on the representation and differential as
        found via ``self.get_representation_component_names``.
    
        TODO: We should handle dynamic representation transforms here (e.g.,
        `.cylindrical`) instead of defining properties as below.
        """
    
        # attr == '_representation' is likely from the hasattr() test in the
        # representation property which is used for
        # self.representation_component_names.
        #
        # Prevent infinite recursion here.
        if attr.startswith('_'):
            return self.__getattribute__(attr)  # Raise AttributeError.
    
        repr_names = self.representation_component_names
        if attr in repr_names:
            if self._data is None:
                self.data  # this raises the "no data" error by design - doing it
                # this way means we don't have to replicate the error message here
    
            rep = self.represent_as(self.representation_type,
                                    in_frame_units=True)
            val = getattr(rep, repr_names[attr])
            return val
    
        diff_names = self.get_representation_component_names('s')
        if attr in diff_names:
            if self._data is None:
                self.data  # see above.
            # TODO: this doesn't work for the case when there is only
            # unitspherical information. The differential_type gets set to the
            # default_differential, which expects full information, so the
            # units don't work out
            rep = self.represent_as(in_frame_units=True,
                                    **self.get_representation_cls(None))
            val = getattr(rep.differentials['s'], diff_names[attr])
            return val
    
>       return self.__getattribute__(attr)  # Raise AttributeError.
E       AttributeError: 'FakeFrame' object has no attribute 'obstime'

astropy/coordinates/baseframe.py:1556: AttributeError

[Cadair]

This is now fixed in SunPy master.

[Cadair]

All the SunPy frames have obstime but not all the astropy ones. The issue here is that astropy frames are being passed to the sunpy function, which is maybe erroneously assuming it’s only getting passed SunPy frames.

I think this is actually a sunpy issue.