tests: install "qemu" namespace package into venv

This patch adds the "qemu" namespace package to the $build/tests/venv
directory. It does so in "editable" mode, which means that changes to
the source python directory will actively be reflected by the venv.

This patch also then removes any sys.path hacking from the avocado test
scripts directly. By doing this, the environment of where to find these
packages is managed entirely by the virtual environment and not by the
scripts themselves.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220526000921.1581503-7-jsnow@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tests/Makefile.include

@@ -110,6 +110,7 @@ quiet-venv-pip = $(quiet-@)$(call quiet-command-run, \
 
 $(TESTS_VENV_DIR): $(TESTS_VENV_REQ)
 	$(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-command, touch $@)
 

tests/avocado/avocado_qemu/__init__.py

@@ -21,6 +21,11 @@
 from avocado.utils import cloudinit, datadrainer, process, ssh, vmimage
 from avocado.utils.path import find_command
 
+from qemu.machine import QEMUMachine
+from qemu.utils import (get_info_usernet_hostfwd_port, kvm_available,
+                        tcg_available)
+
+
 #: The QEMU build root directory.  It may also be the source directory
 #: if building from the source dir, but it's safer to use BUILD_DIR for
 #: that purpose.  Be aware that if this code is moved outside of a source
@@ -35,12 +40,6 @@
 else:
     SOURCE_DIR = BUILD_DIR
 
-sys.path.append(os.path.join(SOURCE_DIR, 'python'))
-
-from qemu.machine import QEMUMachine
-from qemu.utils import (get_info_usernet_hostfwd_port, kvm_available,
-                        tcg_available)
-
 
 def has_cmd(name, args=None):
     """

tests/avocado/virtio_check_params.py

@@ -22,7 +22,6 @@
 import re
 import logging
 
-sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..', 'python'))
 from qemu.machine import QEMUMachine
 from avocado_qemu import QemuSystemTest
 from avocado import skip

tests/avocado/virtio_version.py

@@ -11,7 +11,6 @@
 import sys
 import os
 
-sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..', 'python'))
 from qemu.machine import QEMUMachine
 from avocado_qemu import QemuSystemTest
 

tests/requirements.txt

@@ -1,5 +1,6 @@
 # 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