python: add Makefile for some common tasks

Add "make venv" to create the pipenv-managed virtual environment that
contains our explicitly pinned dependencies.

Add "make check" to run the python linters [in the host execution
environment].

Add "make venv-check" which combines the above two: create/update the
venv, then run the linters in that explicitly managed environment.

Add "make develop" which canonizes the runes needed to get both the
linting pre-requisites (the "[devel]" part), and the editable
live-install (the "-e" part) of these python libraries.

make clean: delete miscellaneous python packaging output possibly
created by pipenv, pip, or other python packaging utilities

make distclean: delete the above, the .venv, and the editable "qemu"
package forwarder (qemu.egg-info) if there is one.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Cleber Rosa <crosa@redhat.com>
Tested-by: Cleber Rosa <crosa@redhat.com>
Message-id: 20210527211715.394144-29-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
diff --git a/python/Makefile b/python/Makefile
new file mode 100644
index 0000000..a9da168
--- /dev/null
+++ b/python/Makefile
@@ -0,0 +1,43 @@
+.PHONY: help venv venv-check check clean distclean develop
+
+help:
+	@echo "python packaging help:"
+	@echo ""
+	@echo "make venv:       Create pipenv's virtual environment."
+	@echo "    NOTE: Requires Python 3.6 and pipenv."
+	@echo "          Will download packages from PyPI."
+	@echo "    Hint: (On Fedora): 'sudo dnf install python36 pipenv'"
+	@echo ""
+	@echo "make venv-check: run linters using pipenv's virtual environment."
+	@echo "    Hint: If you don't know which test to run, run this one!"
+	@echo ""
+	@echo "make develop:    Install deps for 'make check', and"
+	@echo "                 the qemu libs in editable/development mode."
+	@echo ""
+	@echo "make check:      run linters using the current environment."
+	@echo ""
+	@echo "make clean:      remove package build output."
+	@echo ""
+	@echo "make distclean:  remove venv files, qemu package forwarder,"
+	@echo "                 built distribution files, and everything"
+	@echo "                 from 'make clean'."
+
+venv: .venv
+.venv: Pipfile.lock
+	@PIPENV_VENV_IN_PROJECT=1 pipenv sync --dev --keep-outdated
+	@touch .venv
+
+venv-check: venv
+	@pipenv run make check
+
+develop:
+	pip3 install -e .[devel]
+
+check:
+	@avocado --config avocado.cfg run tests/
+
+clean:
+	python3 setup.py clean --all
+
+distclean: clean
+	rm -rf qemu.egg-info/ .venv/ dist/
diff --git a/python/PACKAGE.rst b/python/PACKAGE.rst
index 05ea778..b0b86cc 100644
--- a/python/PACKAGE.rst
+++ b/python/PACKAGE.rst
@@ -35,3 +35,9 @@
 Optional packages necessary for running code quality analysis for this
 package can be installed with the optional dependency group "devel":
 ``pip install qemu[devel]``.
+
+``make develop`` can be used to install this package in editable mode
+(to the current environment) *and* bring in testing dependencies in one
+command.
+
+``make check`` can be used to run the available tests.
diff --git a/python/README.rst b/python/README.rst
index 6bd2c6b..dcf9938 100644
--- a/python/README.rst
+++ b/python/README.rst
@@ -28,6 +28,9 @@
 packages for testing this package. They are not runtime requirements,
 and are not needed to simply use these libraries.
 
+Running ``make develop`` will pull in all testing dependencies and
+install QEMU in editable mode to the current environment.
+
 See `Installing packages using pip and virtual environments
 <https://packaging.python.org/guides/installing-using-pip-and-virtual-environments/>`_
 for more information.
@@ -39,6 +42,9 @@
 - ``qemu/`` Python package source directory.
 - ``tests/`` Python package tests directory.
 - ``avocado.cfg`` Configuration for the Avocado test-runner.
+  Used by ``make check`` et al.
+- ``Makefile`` provides some common testing/installation invocations.
+  Try ``make help`` to see available targets.
 - ``MANIFEST.in`` is read by python setuptools, it specifies additional files
   that should be included by a source distribution.
 - ``PACKAGE.rst`` is used as the README file that is visible on PyPI.org.