Merge branch 'brew' into gh-workflows

Makefile

@@ -16,16 +16,18 @@ $(DEVENVPIP):
 $(SYSDEPS_INSTALLED): sysdeps.mk
 ifeq ($(shell command -v apt-get > /dev/null; echo $$?),0)
 	sudo apt-get install --yes $(APT_SYSDEPS)
+else ifeq ($(shell command -v brew > /dev/null; echo $$?),0)
+	brew install $(BREW_SYSDEPS)
 else
 	@echo 'System dependencies can only be installed automatically on'
-	@echo 'systems with "apt-get". On OSX you can manually use Homebrew'
-	@echo 'if there are missing dependencies corresponding to the following'
-	@echo 'Debian packages:'
+	@echo 'systems with "apt-get" or "brew". Dependencies correspond to'
+	@echo 'the following Debian packages:'
 	@echo '$(APT_SYSDEPS).'
 endif
+	@command -v tox > /dev/null || (echo "Could not find tox on the PATH"; exit 1)
+	@command -v isort > /dev/null || (echo "Could not find isort on the PATH"; exit 1)
 	touch $(SYSDEPS_INSTALLED)
 
-
 .PHONY: check
 check: setup lint
 	@tox

sysdeps.mk

@@ -1 +1,2 @@
 APT_SYSDEPS = python3-pip python3-setuptools libsodium-dev libffi-dev libssl-dev tox isort
+BREW_SYSDEPS = python3 libsodium libffi openssl tox isort

tox.ini

@@ -1,9 +1,11 @@
-# Copyright 2017 Canonical Ltd.
+# Copyright 2017,2024 Canonical Ltd.
 # Licensed under the LGPLv3, see LICENCE file for details.
 
 [tox]
 envlist = lint, py27, py35, docs
 # envlist = py27
+# If the system has tox < 4.8, installs a newer tox in a venv.
+minversion = 4.8
 
 [testenv]
 setenv =