iotests: add 'qemu' package location to PYTHONPATH in testenv

We can drop the sys.path hacking in various places by doing
this. Additionally, by doing it in one place right up top, we can print
interesting warnings in case the environment does not look correct. (See
next commit.)

If we ever decide to change how the environment is crafted, all of the
"help me find my python packages" goop is all in one place, right in one
function.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210923180715.4168522-2-jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

tests/qemu-iotests/235

@@ -24,8 +24,6 @@ import os
 import iotests
 from iotests import qemu_img_create, qemu_io, file_path, log
 
-sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..', 'python'))
-
 from qemu.machine import QEMUMachine
 
 iotests.script_initialize(supported_fmts=['qcow2'])

tests/qemu-iotests/297

@@ -68,12 +68,6 @@ def run_linters():
     # Todo notes are fine, but fixme's or xxx's should probably just be
     # fixed (in tests, at least)
     env = os.environ.copy()
-    qemu_module_path = os.path.join(os.path.dirname(__file__),
-                                    '..', '..', 'python')
-    try:
-        env['PYTHONPATH'] += os.pathsep + qemu_module_path
-    except KeyError:
-        env['PYTHONPATH'] = qemu_module_path
     subprocess.run(('pylint-3', '--score=n', '--notes=FIXME,XXX', *files),
                    env=env, check=False)
 

tests/qemu-iotests/300

@@ -24,11 +24,10 @@ import random
 import re
 from typing import Dict, List, Optional
 
+from qemu.machine import machine
+
 import iotests
 
-# Import qemu after iotests.py has amended sys.path
-# pylint: disable=wrong-import-order
-from qemu.machine import machine
 
 BlockBitmapMapping = List[Dict[str, object]]
 

tests/qemu-iotests/iotests.py

@@ -36,8 +36,6 @@ import unittest
 
 from contextlib import contextmanager
 
-# pylint: disable=import-error, wrong-import-position
-sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..', 'python'))
 from qemu.machine import qtest
 from qemu.qmp import QMPMessage
 

tests/qemu-iotests/testenv.py

@@ -108,12 +108,15 @@ class TestEnv(ContextManager['TestEnv']):
              SAMPLE_IMG_DIR
              OUTPUT_DIR
         """
-        self.pythonpath = os.getenv('PYTHONPATH')
-        if self.pythonpath:
-            self.pythonpath = self.source_iotests + os.pathsep + \
-                self.pythonpath
-        else:
-            self.pythonpath = self.source_iotests
+
+        # Path where qemu goodies live in this source tree.
+        qemu_srctree_path = Path(__file__, '../../../python').resolve()
+
+        self.pythonpath = os.pathsep.join(filter(None, (
+            self.source_iotests,
+            str(qemu_srctree_path),
+            os.getenv('PYTHONPATH'),
+        )))
 
         self.test_dir = os.getenv('TEST_DIR',
                                   os.path.join(os.getcwd(), 'scratch'))

tests/qemu-iotests/tests/mirror-top-perms

@@ -20,13 +20,12 @@
 #
 
 import os
+
+import qemu
+
 import iotests
 from iotests import qemu_img
 
-# Import qemu after iotests.py has amended sys.path
-# pylint: disable=wrong-import-order
-import qemu
-
 
 image_size = 1 * 1024 * 1024
 source = os.path.join(iotests.test_dir, 'source.img')