qemu-iotests: move command line and environment handling from TestRunner to TestEnv

In the next patch, "check" will learn how to execute a test script without
going through TestRunner.  To enable this, keep only the text output
and subprocess handling in the TestRunner; move into TestEnv the logic
to prepare for running a subprocess.

Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Tested-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20210323181928.311862-4-pbonzini@redhat.com>
Message-Id: <20210503110110.476887-4-pbonzini@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>

1 files changed, 16 insertions, 1 deletions

diff --git a/tests/qemu-iotests/testenv.py b/tests/qemu-iotests/testenv.py
index 6d27712617..fca3a609e0 100644
--- a/tests/qemu-iotests/testenv.py
+++ b/tests/qemu-iotests/testenv.py
@@ -25,7 +25,7 @@ import collections
 import random
 import subprocess
 import glob
-from typing import Dict, Any, Optional, ContextManager
+from typing import List, Dict, Any, Optional, ContextManager
 
 
 def isxfile(path: str) -> bool:
@@ -74,6 +74,21 @@ class TestEnv(ContextManager['TestEnv']):
                      'CACHEMODE_IS_DEFAULT', 'IMGFMT_GENERIC', 'IMGOPTSSYNTAX',
                      'IMGKEYSECRET', 'QEMU_DEFAULT_MACHINE', 'MALLOC_PERTURB_']
 
+    def prepare_subprocess(self, args: List[str]) -> Dict[str, str]:
+        if self.debug:
+            args.append('-d')
+
+        with open(args[0], encoding="utf-8") as f:
+            try:
+                if f.readline().rstrip() == '#!/usr/bin/env python3':
+                    args.insert(0, self.python)
+            except UnicodeDecodeError:  # binary test? for future.
+                pass
+
+        os_env = os.environ.copy()
+        os_env.update(self.get_env())
+        return os_env
+
     def get_env(self) -> Dict[str, str]:
         env = {}
         for v in self.env_variables: