python: Configure tox to skip missing interpreters

Currently tox tests against the installed interpreters, however if any
supported interpreter is absent then it will return fail. It seems not
reasonable to expect developers to have all supported interpreters
installed on their systems. Luckily tox can be configured to skip
missing interpreters.

This changed the tox setup so that missing interpreters are skipped by
default. On the CI, however, we still want to enforce it tests
against all supported. This way on CI the
--skip-missing-interpreters=false option is passed to tox.

Signed-off-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Message-Id: <20210630184546.456582-1-wainersm@redhat.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Cleber Rosa <crosa@redhat.com>

.gitlab-ci.d/static_checks.yml

@@ -43,6 +43,7 @@ check-python-tox:
     - make -C python check-tox
   variables:
     GIT_DEPTH: 1
+    QEMU_TOX_EXTRA_ARGS: --skip-missing-interpreters=false
   needs:
     job: python-container
   allow_failure: true

python/Makefile

@@ -1,4 +1,5 @@
 QEMU_VENV_DIR=.dev-venv
+QEMU_TOX_EXTRA_ARGS ?=
 
 .PHONY: help
 help:
@@ -15,6 +16,8 @@ help:
 	@echo "    These tests use the newest dependencies."
 	@echo "    Requires: Python 3.6 - 3.10, and tox."
 	@echo "    Hint (Fedora): 'sudo dnf install python3-tox python3.10'"
+	@echo "    The variable QEMU_TOX_EXTRA_ARGS can be use to pass extra"
+	@echo "    arguments to tox".
 	@echo ""
 	@echo "make check-dev:"
 	@echo "    Run tests in a venv against your default python3 version."
@@ -87,7 +90,7 @@ check:
 
 .PHONY: check-tox
 check-tox:
-	@tox
+	@tox $(QEMU_TOX_EXTRA_ARGS)
 
 .PHONY: clean
 clean:

python/setup.cfg

@@ -121,6 +121,7 @@ multi_line_output=3
 
 [tox:tox]
 envlist = py36, py37, py38, py39, py310
+skip_missing_interpreters = true
 
 [testenv]
 allowlist_externals = make