refactor(tests):

[wpbonelli]

Follows up on #1130 and picks up some threads originally in #1052

• Use keepable temp dir fixtures and smoke testing marker/CLI option from modflow-devtools
• Add smoke test job to ci.yml, only trigger matrix jobs if smoke tests pass
• Remove pymake as a testing dependency, replace pymake and local utility usages with devtools or FloPy equivalents
  • files removed:
    • disu_util.py
    • binary_file_writer.py
    • budget_file_compare.py
  • moved autotest/scripts/cross_section_functions.py -> autotest/cross_section_functions.py for import without altering sys.path
• Add optional --path (short -p) argument to update_flopy.py CLI, defaults to existing location doc/mf6io/mf6ivar/dfn
  • script can also be run with pytest, in which case pytest-order is used for ordering
• Partially refactor a subset of GWF tests with pytest-cases. This is a proof of concept for decoupling test cases from test functions, meant to demo how existing test cases could be incrementally refactored to plug into a shared test function. Implementations range from a minimal switch to pytest-cases, keeping things in the original file, to more extensive refactoring using the Case utility from devtools. Affected files include:
  • test_gwf_buy_lak02.py: cases and test function both kept in original script
  • test_gwf_csub_sk01.py: cases and test function both kept in original script
  • test_gwf_maw04.py: cases defined in original script, plugged into shared test function
  • test_gwf_maw_cases.py: broadly refactored cases previously in test_gwf_maw0[1-3].py, plugged into shared function
  • test_gwf.py: shared test function, cases testing any package can be plugged in
• Rename Simulation to TestSimulation to disambiguate from Flopy and ModflowAPI
• Rename testing_framework to TestFramework (shared test function could replace framework class if refactor proceeds)
• Require flopy (remove try/except imports) since it's documented in DEVELOPER.md and included in environment.yml
• Remove extra code allowing test scripts to be run directly with python (without pytest) — tests depend on several pytest features so it seems reasonable to require it as a testing dependency, and --original-regression, --model and --package filtering options are now supported by pytest.
• Provide REPOS_PATH env var to testing steps in CI. This is not strictly required since the repos are checked out to the default search location used by devtools (level with modflow6) but probably still best to be explicit.
• Update/expand DEVELOPER.md to reflect updates described here. The recent changes should be mostly transparent but if errors are encountered in a local development environment, some things to check include:
  • modflow-devtools>=0.1.4 should be installed
  • flopy must be installed from a recent version of the develop branch (at least modflowpy/flopy@94cd19d)
  • if external model repositories MODFLOW-USGS/modflow6-testmodels, MODFLOW-USGS/modflow6-largetestmodels and MODFLOW-USGS/modflow6-examples are not cloned side-by-side with the modflow6 repo, the REPOS_PATH environment variable must point to the folder containing the model repositories
  • the --pak, --sim and --match options previously used for external model tests are converted to --model and --package options supported by pytest — for finer-grained control the utility functions with which the CLI opts are implemented may be used directly