improve doctests coverage in graphs

[dcoudert]

Add doctests to reach 100% coverage in

• graphs/generic_graph.py: was 99.1% (227 of 229)
• graphs/graph_decompositions/fast_digraph.pyx: was 33.3% (1 of 3)
• graphs/graph_list.py: was 77.8% (7 of 9)
• graphs/tutte_polynomial.py: was 95.2% (20 of 21)

What remains:

• graphs/graph_database.py: 93.3% (14 of 15). The missing doctest is in method _gen_interact_func which uses sagenb. So it will certainly be removed in the future.
• graphs/graph_generators.py: 92.9% (13 of 14). The missing doctest is in method __append_to_doc used to feed global variable __doc__ used by sphinx. Don't know how to doctest that.

CC: @fchapoton

Component: graph theory

Author: David Coudert

Branch/Commit: eadfe03

Reviewer: Frédéric Chapoton, François Bissey

Issue created by migration from https://trac.sagemath.org/ticket/30377

[dcoudert]

Branch: public/graphs/30377_doctests

[dcoudert]

Commit: 1a4386a

[dcoudert]

comment:1

The added doctests allow to reach 100% coverage, but are not very useful by themself.

---

New commits:

8206e2d	trac #30377: improve generic_graph.py
6883f31	trac #30377: graph_list.py and fast_digraph.pyx
1a4386a	trac #30377: tutte_polynomial.py

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

d8955e0

trac #30377: fix block syntax in fast_digraph.pyx

[sagetrac-git]

Changed commit from 1a4386a to d8955e0

[fchapoton]

comment:3

ok, feu vert

[fchapoton]

Reviewer: Frédéric Chapoton

[dcoudert]

comment:4

Thanks!

[kiwifb]

comment:5

Sorry, I am a bit annoyed already today.

Whose great idea was is to introduce new calls to installed_packages or any other of those functions in sage/misc/packages.py that we are desperately trying to purge to make sage more packageable?

It may be a lesser offence in a doctest than at runtime but it is still objectionable. If Volker keeps this ticket merged in the current state, be assured there will be a follow up ticket to remove those bits.

[dcoudert]

comment:6

Sorry for that.

Should I change the doctest to something like that ?

sage: igraph_feature().is_present()  # optional - python_igraph 
True

or do you have a better suggestion ?

[kiwifb]

comment:7

I sincerely have no better suggestion. Playing with automagically discoverable dependency at runtime is always a bit fun. I notice some other python packages usually do a runtime detection at the beginning of the test run and then skip what is not available. sage is taking a very different approach.

And testing the runtime tester is always going to leave you in a funny position.

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

a9aa831	trac #30377: merged with 9.2.beta9
eadfe03	trac #30377: avoid use of intalled_packages

[sagetrac-git]

Changed commit from d8955e0 to eadfe03

[dcoudert]

comment:9

Should be better this way. The alternative is to simply remove the test.

[kiwifb]

Changed reviewer from Frédéric Chapoton to Frédéric Chapoton, François Bissey

[kiwifb]

comment:11

OK, Volker finally did not include the old version of the ticket in 9.2.beta10. Thanks for the correction.

[vbraun]

Changed branch from public/graphs/30377_doctests to eadfe03