[RFC PATCH v3 0/7] tests: run python tests under a venv

[RFC PATCH v3 0/7] tests: run python tests under a venv

[John Snow]

Hi, here's another RFC for bringing external Python dependencies to the
QEMU test suite.

This is mostly a refresh of a version I sent out before, but mixes in my
VM improvement test as an optional pre-requisite to improve VM test
stability to ensure that the BSDs all pass with the new
infrastructure. (And our oldest supported Debian and Ubuntu targets,
too.)

(Note: this requires dropping support for Ubuntu 18.04, which ships with
a version of setuptools that is simply too old.)

This patchset is still not without some problems that I am working on,
but progress has been slow.

Problems I am aware of:

- This version of the patch series does not itself enforce any
  offline-only behavior for venv creation, but downstreams can modify
  any call to 'mkvenv' to pass '--offline'. I am working on a configure
  file toggle to swap the default behavior when running tests.

- iotests will now actually never run mypy or pylint tests by default
  anymore, because the bootstrapper won't select those packages by
  default, and the virtual environment won't utilize the system
  packages, so iotest 297 will just "skip" all of the time now.

  The reason we don't want to install these packages by default is
  because we don't want to add dependencies on mypy and pylint for
  downstream builds.

  With these patches, 297 would still work if you manually opened up the
  testing venv and installed suitable mypy/pylint packages there. I
  could also add a new optional dependency group, and one could
  theoretically invoke a once-per-build-dir command of 'make
  check-venv-iotests' to help make the process only semi-manual, but
  it's still annoying.

  Ideally, the python checks in qemu.git/python/ can handle the same
  tests as 297 does -- but we need to give a shorthand invocation like
  "make check-python" that is excluded from the default "make check" to
  allow block developers to quickly opt-in to the same tests.

  I've covered some of the problems here on-list before:
  https://lists.gnu.org/archive/html/qemu-devel/2022-05/msg03661.html

  ...But I haven't quite solved them yet.

- iotests can now self-bootstrap the venv when it isn't present, but
  this self-bootstrapping has some issues in that because it skips the
  Makefile magic, it cannot update the venv when changes are made to the
  venv configuration piece.

That's all for now. Work on the configure file integration is ongoing. I
don't know if I'll beat soft freeze (It's looking unlikely given the
amount of IRL issues I am juggling right now), but I'm hoping to push as
much of this forward as I can to try and get some testing in for RC
phase to determine what problems might exist that I haven't noticed yet.

--js

John Snow (7):
  tests: create optional tests/venv dependency groups
  tests: pythonize test venv creation
  tests: Remove spurious pip warnings on Ubuntu20.04
  tests/vm: add venv pre-requisites to VM building recipes
  tests: add 'check-venv' as a dependency of 'make check'
  iotests: use tests/venv for running tests
  iotests: self-bootstrap testing venv

 tests/Makefile.include        |  32 +++---
 tests/mkvenv.py               | 187 ++++++++++++++++++++++++++++++++++
 tests/qemu-iotests/testenv.py |  25 +++--
 tests/requirements.txt        |   6 --
 tests/setup.cfg               |  20 ++++
 tests/setup.py                |  16 +++
 tests/vm/netbsd               |   1 +
 7 files changed, 262 insertions(+), 25 deletions(-)
 create mode 100644 tests/mkvenv.py
 delete mode 100644 tests/requirements.txt
 create mode 100644 tests/setup.cfg
 create mode 100644 tests/setup.py

-- 
2.34.3

[RFC PATCH v3 1/7] tests: create optional tests/venv dependency groups

[John Snow]

This patch uses a dummy package and setup.cfg/setup.py files to manage
optional dependency groups for the test venv specification. Now, there's
a core set of dependencies which for now includes just "qemu" (but soon,
qemu.qmp) and a separate, optional 'avocado' group that includes
avocado-framework and pycdlib.

Practical upshot: We install only a minimum of things for the majority
of check-* targets, but allow optional add-ons to be processed when
running avocado tests. This will spare downstreams from having to add
more dependencies than is necessary as a build dependencies when
invoking "make check".

(We also keep both sets of dependencies in one file, which is helpful
for review to ensure that different option groups don't conflict with
one another.)

NOTE: There is a non-fatal caveat introduced by this patch on Ubuntu
20.04 systems; see the subsequent commit "tests: Remove spurious pip
warnings on Ubuntu20.04" for more information.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 tests/Makefile.include | 21 ++++++++++++++-------
 tests/requirements.txt |  6 ------
 tests/setup.cfg        | 20 ++++++++++++++++++++
 tests/setup.py         | 16 ++++++++++++++++
 4 files changed, 50 insertions(+), 13 deletions(-)
 delete mode 100644 tests/requirements.txt
 create mode 100644 tests/setup.cfg
 create mode 100644 tests/setup.py

diff --git a/tests/Makefile.include b/tests/Makefile.include
index 3accb83b132..82c697230e0 100644
--- a/tests/Makefile.include
+++ b/tests/Makefile.include
@@ -81,13 +81,13 @@ clean-tcg: $(CLEAN_TCG_TARGET_RULES)
 
 # Python venv for running tests
 
-.PHONY: check-venv check-avocado check-acceptance check-acceptance-deprecated-warning
+.PHONY: check-venv check-venv-avocado check-avocado check-acceptance \
+        check-acceptance-deprecated-warning
 
 # Build up our target list from the filtered list of ninja targets
 TARGETS=$(patsubst libqemu-%.fa, %, $(filter libqemu-%.fa, $(ninja-targets)))
 
 TESTS_VENV_DIR=$(BUILD_DIR)/tests/venv
-TESTS_VENV_REQ=$(SRC_PATH)/tests/requirements.txt
 TESTS_RESULTS_DIR=$(BUILD_DIR)/tests/results
 TESTS_PYTHON=$(TESTS_VENV_DIR)/bin/python3
 ifndef AVOCADO_TESTS
@@ -108,10 +108,16 @@ quiet-venv-pip = $(quiet-@)$(call quiet-command-run, \
     $(TESTS_PYTHON) -m pip -q --disable-pip-version-check $1, \
     "VENVPIP","$1")
 
-$(TESTS_VENV_DIR): $(TESTS_VENV_REQ)
+# Core dependencies for tests/venv
+$(TESTS_VENV_DIR): $(SRC_PATH)/tests/setup.cfg $(SRC_PATH)/python/setup.cfg
 	$(call quiet-command, $(PYTHON) -m venv $@, VENV, $@)
 	$(call quiet-venv-pip,install -e "$(SRC_PATH)/python/")
-	$(call quiet-venv-pip,install -r $(TESTS_VENV_REQ))
+	$(call quiet-venv-pip,install "$(SRC_PATH)/tests/")
+	$(call quiet-command, touch $@)
+
+# Optional avocado dependencies for tests/venv
+$(TESTS_VENV_DIR)/avocado: $(TESTS_VENV_DIR)
+	$(call quiet-venv-pip,install "$(SRC_PATH)/tests/[avocado]")
 	$(call quiet-command, touch $@)
 
 $(TESTS_RESULTS_DIR):
@@ -119,6 +125,7 @@ $(TESTS_RESULTS_DIR):
             MKDIR, $@)
 
 check-venv: $(TESTS_VENV_DIR)
+check-venv-avocado: $(TESTS_VENV_DIR)/avocado
 
 FEDORA_31_ARCHES_TARGETS=$(patsubst %-softmmu,%, $(filter %-softmmu,$(TARGETS)))
 FEDORA_31_ARCHES_CANDIDATES=$(patsubst ppc64,ppc64le,$(FEDORA_31_ARCHES_TARGETS))
@@ -126,16 +133,16 @@ FEDORA_31_ARCHES := x86_64 aarch64 ppc64le s390x
 FEDORA_31_DOWNLOAD=$(filter $(FEDORA_31_ARCHES),$(FEDORA_31_ARCHES_CANDIDATES))
 
 # download one specific Fedora 31 image
-get-vm-image-fedora-31-%: check-venv
+get-vm-image-fedora-31-%: check-venv-avocado
 	$(call quiet-command, \
              $(TESTS_PYTHON) -m avocado vmimage get \
              --distro=fedora --distro-version=31 --arch=$*, \
 	"AVOCADO", "Downloading avocado tests VM image for $*")
 
 # download all vm images, according to defined targets
-get-vm-images: check-venv $(patsubst %,get-vm-image-fedora-31-%, $(FEDORA_31_DOWNLOAD))
+get-vm-images: check-venv-avocado $(patsubst %,get-vm-image-fedora-31-%, $(FEDORA_31_DOWNLOAD))
 
-check-avocado: check-venv $(TESTS_RESULTS_DIR) get-vm-images
+check-avocado: check-venv-avocado $(TESTS_RESULTS_DIR) get-vm-images
 	$(call quiet-command, \
             $(TESTS_PYTHON) -m avocado \
             --show=$(AVOCADO_SHOW) run --job-results-dir=$(TESTS_RESULTS_DIR) \
diff --git a/tests/requirements.txt b/tests/requirements.txt
deleted file mode 100644
index 0ba561b6bdf..00000000000
--- a/tests/requirements.txt
+++ /dev/null
@@ -1,6 +0,0 @@
-# Add Python module requirements, one per line, to be installed
-# in the tests/venv Python virtual environment. For more info,
-# refer to: https://pip.pypa.io/en/stable/user_guide/#id1
-# Note that qemu.git/python/ is always implicitly installed.
-avocado-framework==88.1
-pycdlib==1.11.0
diff --git a/tests/setup.cfg b/tests/setup.cfg
new file mode 100644
index 00000000000..263a5de01af
--- /dev/null
+++ b/tests/setup.cfg
@@ -0,0 +1,20 @@
+# This file represents a "dummy" package that expresses
+# the dependencies necessary to run the various python-based
+# test suites in the qemu.git tree.
+[metadata]
+name = qemu.dummy_tests
+version = 0.0.0
+description = qemu.git testing dummy package
+
+[options]
+packages =
+python_requires = >= 3.6
+install_requires =
+    qemu  # Note: A special setup script will always install 'qemu' from
+          # qemu.git/python. It doesn't have a meaningful/real version.
+
+[options.extras_require]
+# Extra dependencies required by the avocado tests.
+avocado =
+    avocado-framework<89.0,>=88.1
+    pycdlib<2.0,>=1.11.0
diff --git a/tests/setup.py b/tests/setup.py
new file mode 100644
index 00000000000..c99fe5d1725
--- /dev/null
+++ b/tests/setup.py
@@ -0,0 +1,16 @@
+# This setup file is just-enough-config to allow pip to bootstrap a
+# testing environment. It is not meant to be executed directly.
+# See also: setup.cfg
+
+import setuptools
+import pkg_resources
+
+
+def main():
+    # https://medium.com/@daveshawley/safely-using-setup-cfg-for-metadata-1babbe54c108
+    pkg_resources.require('setuptools>=39.2')
+    setuptools.setup()
+
+
+if __name__ == '__main__':
+    main()
-- 
2.34.3

[RFC PATCH v3 2/7] tests: pythonize test venv creation

[John Snow]

This splits the venv creation logic out of the Makefile and into a
Python script.

One reason for doing this is to be able to call the venv bootstrapper
from places outside of the Makefile, e.g. configure and iotests. Another
reason is to be able to add "offline" logic to modify the behavior of
the script in certain circumstances.

RFC: I don't like how I have an entire "enter_venv" function here, and
by the end of the series, completely separate logic for entering a venv
in testenv.py -- but they both operate in different ways: this patch
offers a method that alters the current ENV immediately, whereas the
testenv.py method alters a copied ENV that is explicitly passed to
subprocesses.

Still, there's a bit more boilerplate than I'd like, but it's probably
fine and it probably won't need to be updated much, but... less code is
usually better.

But, even if I did write it more generically here; iotests wouldn't be
able to use it anyway, because importing it would mean more sys.path
hacking. So... eh?

Signed-off-by: John Snow <jsnow@redhat.com>
---
 tests/Makefile.include |  16 ++--
 tests/mkvenv.py        | 186 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 192 insertions(+), 10 deletions(-)
 create mode 100644 tests/mkvenv.py

diff --git a/tests/Makefile.include b/tests/Makefile.include
index 82c697230e0..d8af6a38112 100644
--- a/tests/Makefile.include
+++ b/tests/Makefile.include
@@ -104,21 +104,17 @@ else
 	AVOCADO_CMDLINE_TAGS=$(addprefix -t , $(AVOCADO_TAGS))
 endif
 
-quiet-venv-pip = $(quiet-@)$(call quiet-command-run, \
-    $(TESTS_PYTHON) -m pip -q --disable-pip-version-check $1, \
-    "VENVPIP","$1")
-
 # Core dependencies for tests/venv
 $(TESTS_VENV_DIR): $(SRC_PATH)/tests/setup.cfg $(SRC_PATH)/python/setup.cfg
-	$(call quiet-command, $(PYTHON) -m venv $@, VENV, $@)
-	$(call quiet-venv-pip,install -e "$(SRC_PATH)/python/")
-	$(call quiet-venv-pip,install "$(SRC_PATH)/tests/")
-	$(call quiet-command, touch $@)
+	$(call quiet-command, \
+            $(PYTHON) "$(SRC_PATH)/tests/mkvenv.py" "$@", \
+            MKVENV, $@)
 
 # Optional avocado dependencies for tests/venv
 $(TESTS_VENV_DIR)/avocado: $(TESTS_VENV_DIR)
-	$(call quiet-venv-pip,install "$(SRC_PATH)/tests/[avocado]")
-	$(call quiet-command, touch $@)
+	$(call quiet-command, \
+            $(PYTHON) "$(SRC_PATH)/tests/mkvenv.py" --opt avocado "$<", \
+            MKVENV, $@)
 
 $(TESTS_RESULTS_DIR):
 	$(call quiet-command, mkdir -p $@, \
diff --git a/tests/mkvenv.py b/tests/mkvenv.py
new file mode 100644
index 00000000000..0667106d6aa
--- /dev/null
+++ b/tests/mkvenv.py
@@ -0,0 +1,186 @@
+"""
+mkvenv - QEMU venv bootstrapping utility
+
+usage: mkvenv.py [-h] [--offline] [--opt OPT] target
+
+Bootstrap QEMU testing venv.
+
+positional arguments:
+  target      Target directory to install virtual environment into.
+
+optional arguments:
+  -h, --help  show this help message and exit
+  --offline   Use system packages and work entirely offline.
+  --opt OPT   Install an optional dependency group.
+"""
+
+# Copyright (C) 2022 Red Hat, Inc.
+#
+# Authors:
+#  John Snow <jsnow@redhat.com>
+#
+# This work is licensed under the terms of the GNU GPL, version 2 or
+# later. See the COPYING file in the top-level directory.
+
+# Do not add any dependencies from outside the stdlib:
+# This script must be usable on its own!
+
+import argparse
+from contextlib import contextmanager
+import logging
+import os
+from pathlib import Path
+import subprocess
+import sys
+from typing import Iterable, Iterator, Union
+import venv
+
+
+def make_venv(
+        venv_path: Union[str, Path],
+        system_site_packages: bool = False
+) -> None:
+    """
+    Create a venv using the python3 'venv' module.
+
+    Identical to:
+    ``python3 -m venv --clear [--system-site-packages] {venv_path}``
+
+    :param venv_path: The target directory
+    :param system_site_packages: If True, allow system packages in venv.
+    """
+    logging.debug("%s: make_venv(venv_path=%s, system_site_packages=%s)",
+                  __file__, str(venv_path), system_site_packages)
+    venv.create(
+        str(venv_path),
+        clear=True,
+        symlinks=os.name != "nt",  # Same as venv CLI's default.
+        with_pip=True,
+        system_site_packages=system_site_packages,
+    )
+
+
+@contextmanager
+def enter_venv(venv_dir: Union[str, Path]) -> Iterator[None]:
+    """Scoped activation of an existing venv."""
+    venv_keys = ('PATH', 'PYTHONHOME', 'VIRTUAL_ENV')
+    old = {k: v for k, v in os.environ.items() if k in venv_keys}
+    vdir = Path(venv_dir).resolve()
+
+    def _delete_keys() -> None:
+        for k in venv_keys:
+            try:
+                del os.environ[k]
+            except KeyError:
+                pass
+
+    try:
+        _delete_keys()
+
+        os.environ['VIRTUAL_ENV'] = str(vdir)
+        os.environ['PATH'] = os.pathsep.join([
+            str(vdir / "bin/"),
+            old['PATH'],
+        ])
+
+        logging.debug("PATH => %s", os.environ['PATH'])
+        logging.debug("VIRTUAL_ENV => %s", os.environ['VIRTUAL_ENV'])
+
+        yield
+
+    finally:
+        _delete_keys()
+        for key, val in old.items():
+            os.environ[key] = val
+
+
+def install(*args: str, offline: bool = False) -> None:
+    """Shorthand for pip install; expected to be used under a venv."""
+    cli_args = ['pip3', '--disable-pip-version-check', '-q', 'install']
+    if offline:
+        cli_args.append('--no-index')
+    cli_args += args
+    print(f"  VENVPIP install {' '.join(args)}")
+    logging.debug(' '.join(cli_args))
+    subprocess.run(cli_args, check=True)
+
+
+def make_qemu_venv(
+        venv_dir: str,
+        options: Iterable[str],
+        offline: bool = False
+) -> None:
+    """
+    Make and initialize a qemu testing venv.
+
+    Forcibly re-creates the venv if it already exists, unless optional
+    dependency groups are specified - in which case, just install the
+    extra dependency groups.
+
+    :param venv_dir: The target directory to install to.
+    :param options:
+        Optional dependency groups of the testing package to install.
+        (e.g. 'avocado'.)
+    :param offline:
+        If true, force offline mode. System packages will be usable from
+        the venv and dependencies will not be fetched from PyPI.
+    """
+    venv_path = Path(venv_dir).resolve()
+    src_root = Path(__file__).joinpath('../..')
+    pysrc_path = src_root.joinpath('python/').resolve()
+    test_src_path = src_root.joinpath('tests/').resolve()
+
+    logging.debug("make_qemu_venv(%s)", venv_dir)
+    logging.debug("sys.executable: %s", sys.executable)
+    logging.debug("resolved:       %s", str(Path(sys.executable).resolve()))
+    logging.debug("venv_dir:       %s", str(venv_path))
+    logging.debug("python source:  %s", str(pysrc_path))
+    logging.debug("tests source:   %s", str(test_src_path))
+
+    do_initialize = not venv_path.exists() or not options
+    if do_initialize:
+        make_venv(venv_path, system_site_packages=offline)
+
+    with enter_venv(venv_path):
+        if do_initialize:
+            install("-e", str(pysrc_path), offline=offline)
+            install(str(test_src_path), offline=offline)
+            venv_path.touch()
+
+        for option in options:
+            dummy = venv_path / option
+            install(f"{test_src_path!s}/[{option}]", offline=offline)
+            dummy.touch()
+
+
+def main() -> int:
+    """CLI interface to make_qemu_venv. See module docstring."""
+    if os.environ.get('DEBUG'):
+        logging.basicConfig(level=logging.DEBUG)
+
+    parser = argparse.ArgumentParser(
+        description="Bootstrap QEMU testing venv.")
+    parser.add_argument(
+        '--offline',
+        action='store_true',
+        help="Use system packages and work entirely offline.",
+    )
+    parser.add_argument(
+        '--opt',
+        type=str,
+        action='append',
+        help="Install an optional dependency group.",
+    )
+    parser.add_argument(
+        'target',
+        type=str,
+        action='store',
+        help="Target directory to install virtual environment into.",
+    )
+    args = parser.parse_args()
+    make_qemu_venv(args.target, args.opt or (), args.offline)
+    return 0
+
+
+if __name__ == '__main__':
+    sys.exit(main())
-- 
2.34.3

[RFC PATCH v3 3/7] tests: Remove spurious pip warnings on Ubuntu20.04

[John Snow]

The version of pip ("20.0.2") that ships with Ubuntu 20.04 has a bug
where it will try to attempt building a wheel even if the "wheel" python
package that enables it to do so is not installed. Even though pip
continues gracefully from source, The result is a lot of irrelevant
failure output.

Upstream pip 20.0.2 does not have this problem, and pip 20.1 introduces
a new info message that informs a user that wheel building is being skipped.

On this version, the output can be silenced by passing --no-binary to
coax pip into skipping that step to begin with. Note, this error does
not seem to show up for the "qemu" package because we install that
package in editable mode. (I think, but did not test, that installing an
empty package in editable mode caused more problems than it fixed.)

Signed-off-by: John Snow <jsnow@redhat.com>
---
 tests/mkvenv.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tests/mkvenv.py b/tests/mkvenv.py
index 0667106d6aa..78f8d0382e0 100644
--- a/tests/mkvenv.py
+++ b/tests/mkvenv.py
@@ -144,7 +144,8 @@ def make_qemu_venv(
     with enter_venv(venv_path):
         if do_initialize:
             install("-e", str(pysrc_path), offline=offline)
-            install(str(test_src_path), offline=offline)
+            install("--no-binary", "qemu.dummy-tests",
+                    str(test_src_path), offline=offline)
             venv_path.touch()
 
         for option in options:
-- 
2.34.3

[RFC PATCH v3 4/7] tests/vm: add venv pre-requisites to VM building recipes

[John Snow]

NetBSD needs "py37-pip" in order to create virtual environments.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 tests/vm/netbsd | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/vm/netbsd b/tests/vm/netbsd
index 45aa9a7fda7..53fe508e487 100755
--- a/tests/vm/netbsd
+++ b/tests/vm/netbsd
@@ -31,6 +31,7 @@ class NetBSDVM(basevm.BaseVM):
         "pkgconf",
         "xz",
         "python37",
+        "py37-pip",
         "ninja-build",
 
         # gnu tools
-- 
2.34.3

[RFC PATCH v3 5/7] tests: add 'check-venv' as a dependency of 'make check'

[John Snow]

This patch adds the 'check-venv' target as a requisite of all meson
driven check-* targets. As of this commit, it will only install the
"qemu" namespace package from the source tree, and nothing else.

In the future, the "qemu" namespace package in qemu.git will begin to
require an external qemu.qmp package, and this would be installed into
this environment as well.

The avocado test dependencies will *not* be pulled into this venv by
default, but they may be added in at a later point in time by running
'make check-avocado' or, without running the tests, 'make
check-venv-avocado'.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 tests/Makefile.include | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tests/Makefile.include b/tests/Makefile.include
index d8af6a38112..d484a335be5 100644
--- a/tests/Makefile.include
+++ b/tests/Makefile.include
@@ -155,6 +155,9 @@ check-acceptance-deprecated-warning:
 
 check-acceptance: check-acceptance-deprecated-warning | check-avocado
 
+# The do-meson-check and do-meson-bench targets are defined in Makefile.mtest
+do-meson-check do-meson-bench: check-venv
+
 # Consolidated targets
 
 .PHONY: check check-clean get-vm-images
-- 
2.34.3

[RFC PATCH v3 6/7] iotests: use tests/venv for running tests

[John Snow]

Essentially, the changes to testenv.py here mimic the changes that occur when
you "source venv/bin/activate.fish" or similar.

(1) update iotest's internal notion of which python binary to use,
(2) export the VIRTUAL_ENV variable,
(3) front-load the venv/bin directory to PATH.

If the venv directory isn't found, raise a friendly exception that tries
to give the human operator a friendly clue as to what's gone wrong. The
subsequent commit attempts to address this shortcoming by teaching
iotests how to invoke the venv bootstrapper in this circumstance
instead.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 tests/qemu-iotests/testenv.py | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/tests/qemu-iotests/testenv.py b/tests/qemu-iotests/testenv.py
index a864c74b123..29404ac94be 100644
--- a/tests/qemu-iotests/testenv.py
+++ b/tests/qemu-iotests/testenv.py
@@ -65,8 +65,9 @@ class TestEnv(ContextManager['TestEnv']):
     # lot of them. Silence pylint:
     # pylint: disable=too-many-instance-attributes
 
-    env_variables = ['PYTHONPATH', 'TEST_DIR', 'SOCK_DIR', 'SAMPLE_IMG_DIR',
-                     'PYTHON', 'QEMU_PROG', 'QEMU_IMG_PROG',
+    env_variables = ['PYTHONPATH', 'VIRTUAL_ENV', 'PYTHON', 'PATH',
+                     'TEST_DIR', 'SOCK_DIR', 'SAMPLE_IMG_DIR',
+                     'QEMU_PROG', 'QEMU_IMG_PROG',
                      'QEMU_IO_PROG', 'QEMU_NBD_PROG', 'QSD_PROG',
                      'QEMU_OPTIONS', 'QEMU_IMG_OPTIONS',
                      'QEMU_IO_OPTIONS', 'QEMU_IO_OPTIONS_NO_FMT',
@@ -102,18 +103,29 @@ def get_env(self) -> Dict[str, str]:
 
     def init_directories(self) -> None:
         """Init directory variables:
+             VIRTUAL_ENV
+             PATH
              PYTHONPATH
              TEST_DIR
              SOCK_DIR
              SAMPLE_IMG_DIR
         """
+        venv_path = Path(self.build_root, 'tests/venv/')
+        if not venv_path.exists():
+            raise FileNotFoundError(
+                f"Virtual environment \"{venv_path!s}\" isn't found."
+                " (Maybe you need to run 'make check-venv'"
+                " from the build dir?)"
+            )
+        self.virtual_env: str = str(venv_path)
 
-        # Path where qemu goodies live in this source tree.
-        qemu_srctree_path = Path(__file__, '../../../python').resolve()
+        self.path = os.pathsep.join((
+            str(venv_path / 'bin'),
+            os.environ['PATH'],
+        ))
 
         self.pythonpath = os.pathsep.join(filter(None, (
             self.source_iotests,
-            str(qemu_srctree_path),
             os.getenv('PYTHONPATH'),
         )))
 
@@ -138,7 +150,7 @@ def init_binaries(self) -> None:
              PYTHON (for bash tests)
              QEMU_PROG, QEMU_IMG_PROG, QEMU_IO_PROG, QEMU_NBD_PROG, QSD_PROG
         """
-        self.python = sys.executable
+        self.python: str = os.path.join(self.virtual_env, 'bin', 'python3')
 
         def root(*names: str) -> str:
             return os.path.join(self.build_root, *names)
@@ -300,6 +312,7 @@ def print_env(self, prefix: str = '') -> None:
 {prefix}GDB_OPTIONS   -- {GDB_OPTIONS}
 {prefix}VALGRIND_QEMU -- {VALGRIND_QEMU}
 {prefix}PRINT_QEMU_OUTPUT -- {PRINT_QEMU}
+{prefix}VIRTUAL_ENV   -- {VIRTUAL_ENV}
 {prefix}"""
 
         args = collections.defaultdict(str, self.get_env())
-- 
2.34.3

[RFC PATCH v3 7/7] iotests: self-bootstrap testing venv

[John Snow]

When iotests are invoked manually from
e.g. $build/tests/qemu-iotests/check, it is not necessarily guaranteed
that we'll have run 'check-venv' yet.

With this patch, teach testenv.py how to create its own environment.

Note: this self-bootstrapping is fairly rudimentary and will miss
certain triggers to refresh the venv. It will miss when new dependencies
are added to either python/setup.cfg or tests/setup.cfg. It can be
coaxed into updating by running 'make check', 'make check-block', 'make
check-venv', etc.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 tests/qemu-iotests/testenv.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tests/qemu-iotests/testenv.py b/tests/qemu-iotests/testenv.py
index 29404ac94be..e985eaf3e97 100644
--- a/tests/qemu-iotests/testenv.py
+++ b/tests/qemu-iotests/testenv.py
@@ -112,10 +112,10 @@ def init_directories(self) -> None:
         """
         venv_path = Path(self.build_root, 'tests/venv/')
         if not venv_path.exists():
-            raise FileNotFoundError(
-                f"Virtual environment \"{venv_path!s}\" isn't found."
-                " (Maybe you need to run 'make check-venv'"
-                " from the build dir?)"
+            mkvenv = Path(self.source_iotests, '../mkvenv.py')
+            subprocess.run(
+                (sys.executable, str(mkvenv), str(venv_path)),
+                check=True,
             )
         self.virtual_env: str = str(venv_path)
 
-- 
2.34.3