We prepare the Sage doctesting module for running in environments where sage.all is not available (#29705).

1. An explicit import in sage.doctest.parsing:

# We need to import from sage.all to avoid circular imports.
from sage.all import RealIntervalField
RIFtol = RealIntervalField(1044)

2. We make the global environment for tests customizable in sage.doctest.forker: in init_sage:

    import sage.repl.ipython_kernel.all_jupyter

and again in DocTestTask._run:

            # Import Jupyter globals to doctest the Jupyter
            # implementation of widgets and interacts
            import sage.repl.ipython_kernel.all_jupyter as sage_all

... which is

"""
All imports for Jupyter
"""

from sage.all_cmdline import *

from .widgets_sagenb import (input_box, text_control, slider,
        range_slider, checkbox, selector, input_grid, color_selector)
from .interact import interact

This is exposed by the new sage-runtest option --environment.

For example, #29865 defines modules such as sage.all__sage_objects. We would invoke sage -t --environment=sage.all__sage_objects to test against this global environment.

3. We ignore errors importing sage.interfaces.

Depends on #29940

CC: @tscrim @fchapoton @orlitzky @kliem @kiwifb

Component: refactoring

Author: Matthias Koeppe

Branch/Commit: 2a602df

Reviewer: Jonathan Kliem

Issue created by migration from https://trac.sagemath.org/ticket/29922