[PATCH] tests/functional/x86_64: Use the right Python interpreter & fix format string

[Thomas Huth <thuth@redhat.com>]

From: Thomas Huth <thuth@redhat.com>

The bad_vmstate test currently fails if the host does not have a "python3"
binary in $PATH because the vmstate-static-checker.py script is executed
directly, so that it gets run via its shebang line. Use the right Python
interpreter from sys.executable to fix this problem.

Additionally, there was another bug with the formatting of the error
message in case of failures: The "+" operator can only concatenate strings,
but not strings with integers. Use a proper format string here instead.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 tests/functional/x86_64/test_bad_vmstate.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tests/functional/x86_64/test_bad_vmstate.py b/tests/functional/x86_64/test_bad_vmstate.py
index 40098a8490b..71a1c0cf638 100755
--- a/tests/functional/x86_64/test_bad_vmstate.py
+++ b/tests/functional/x86_64/test_bad_vmstate.py
@@ -5,6 +5,7 @@
 '''Test whether the vmstate-static-checker script detects problems correctly'''
 
 import subprocess
+import sys
 
 from qemu_test import QemuBaseTest
 
@@ -41,12 +42,13 @@ def test_checker(self):
                                        'vmstate-static-checker.py')
 
         self.log.info('Comparing %s with %s', src_json, dst_json)
-        cp = subprocess.run([checkerscript, '-s', src_json, '-d', dst_json],
+        cp = subprocess.run([sys.executable, checkerscript,
+                             '-s', src_json, '-d', dst_json],
                             stdout=subprocess.PIPE,
                             stderr=subprocess.STDOUT,
                             text=True, check=False)
         if cp.returncode != 13:
-            self.fail('Unexpected return code of vmstate-static-checker: ' +
+            self.fail('Unexpected return code of vmstate-static-checker: %d' %
                       cp.returncode)
         if cp.stdout != EXPECTED_OUTPUT:
             self.log.info('vmstate-static-checker output:\n%s', cp.stdout)
-- 
2.52.0