WIP: add tests that operate at the API level

[bhearsum]

This is inspired by recent frustrations of surprise behaviour by signingscript, and feeling like the current test-every-tiny-little-function-independently tests wouldn't allow for any sort of confident refactoring. These new tests that I'm adding use the same entry point that scriptworker calls into: async_main, and they mock out as little as they possible can. Currently, this is calls to Autograph, and verify_mar_signature, but there will probably be other things mocked out (eg: anything that depends on a signature from a real certificate will need to be mocked).

Running just these new tests alone already achieves 35% coverage overall, and 27% coverage of sign.py:

tests/test_script.py::test_gpg_signing[autograph_gpg] PASSED                                                                                                                                [ 25%]
tests/test_script.py::test_gpg_signing[stage_autograph_gpg] PASSED                                                                                                                          [ 50%]
tests/test_script.py::test_mar_signing[autograph_hash_only_mar384] cPASSED                                                                                                                   [ 75%]
tests/test_script.py::test_mar_signing[stage_autograph_hash_only_mar384] PASSED                                                                                                             [100%]

---------- coverage: platform linux, python 3.11.6-final-0 -----------
Name                              Stmts   Miss Branch BrPart  Cover   Missing
-----------------------------------------------------------------------------
src/signingscript/__init__.py         0      0      0      0   100%
src/signingscript/exceptions.py      11      3      0      0    73%   17, 30, 43
src/signingscript/rcodesign.py       71     58     28      0    13%   25-51, 62-69, 82-90, 99-112, 121-132, 143-152
src/signingscript/script.py          72     29     34      7    55%   32, 34, 37-38, 41-43, 55, 57, 71-74, 112-130, 135-137
src/signingscript/sign.py           863    594    222     14    27%   159-161, 182-184, 202-207, 225-235, 255-269, 294-316, 341-373, 393-407, 430-444, 465-488, 495-500, 508-524, 530-539, 545-562, 568-577, 583-596, 602, 623-630, 637-655, 661-663, 669-687, 693-703, 708-712, 718-721, 727-741, 747-751, 756-763, 769-783, 823-857, 867, 919, 934, 936, 938, 946-948, 952->956, 958-963, 966-969, 975-988, 1014, 1027, 1029, 1054-1063, 1135-1145, 1164-1176, 1192-1200, 1245, 1285-1301, 1324-1332, 1354-1367, 1373-1374, 1393-1468, 1493-1515, 1526-1551, 1558-1559, 1564-1582, 1593-1606, 1611-1619, 1628-1650, 1661-1668, 1677-1681, 1690-1768
src/signingscript/task.py            82     11     36     10    82%   83, 131->130, 134, 157-158, 171, 177, 239, 243, 247, 250, 253
src/signingscript/utils.py           95     33     18      3    59%   63-67, 80-81, 101-104, 132, 143-148, 174-177, 192-203, 229, 243
-----------------------------------------------------------------------------
TOTAL                              1194    728    338     34    35%

This number will obviously go up as I add tests for other signing types.

[ahal]

Overall this stack looks great to me!

[ahal]

Huh, how did I not know that startswith could take a tuple?

[bhearsum]

Neither did I until a few days ago 😆

[bhearsum]

augh, sorry, I just realized this has a whole bunch of stuff from #1085. I'm going to rebase.

[bhearsum]

As much as I'd like to have these, I kindof doubt I'm ever going to be able to prioritize doing this, so I'm just going to close this...

The newly written landoscript is using this style of testing, and can serve as a model for future scripts, or if anyone wants to try to hack it in to an existing one (which is much more difficult to do after the fact vs. when you're writing something new...)