iotests: Update for pylint 2.11.1

1. Ignore the new f-strings warning, we're not interested in doing a
   full conversion at this time.

2. Just mute the unbalanced-tuple-unpacking warning, it's not a real
   error in this case and muting the dozens of callsites is just not
   worth it.

3. Add encodings to read_text().

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210923180715.4168522-7-jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

tests/qemu-iotests/pylintrc

@@ -19,13 +19,17 @@ disable=invalid-name,
         too-many-public-methods,
         # pylint warns about Optional[] etc. as unsubscriptable in 3.9
         unsubscriptable-object,
+        # pylint's static analysis causes false positivies for file_path();
+        # If we really care to make it statically knowable, we'll use mypy.
+        unbalanced-tuple-unpacking,
         # Sometimes we need to disable a newly introduced pylint warning.
         # Doing so should not produce a warning in older versions of pylint.
         bad-option-value,
         # These are temporary, and should be removed:
         missing-docstring,
         too-many-return-statements,
-        too-many-statements
+        too-many-statements,
+        consider-using-f-string,
 
 [FORMAT]
 

tests/qemu-iotests/testrunner.py

@@ -266,12 +266,13 @@ def do_run_test(self, test: str) -> TestResult:
                               diff=file_diff(str(f_reference), str(f_bad)))
 
         if f_notrun.exists():
-            return TestResult(status='not run',
-                              description=f_notrun.read_text().strip())
+            return TestResult(
+                status='not run',
+                description=f_notrun.read_text(encoding='utf-8').strip())
 
         casenotrun = ''
         if f_casenotrun.exists():
-            casenotrun = f_casenotrun.read_text()
+            casenotrun = f_casenotrun.read_text(encoding='utf-8')
 
         diff = file_diff(str(f_reference), str(f_bad))
         if diff: