test.py: fix flake8 complaints

It's good practice to use linters and style formatters for
all scripted languages. Python community is more strict
about formatting guidelines than others, and using
formatters (like flake8 or black) is almost universally
accepted.

test.py was adhering to flake8 standards at some point,
but later this was spoiled by random commits.

test.py

@@ -14,7 +14,6 @@
 import difflib
 import filecmp
 import glob
-import io
 import itertools
 import logging
 import multiprocessing
@@ -142,7 +141,7 @@ def junit_tests(self):
         return self.tests
 
     def add_test_list(self, mode, options):
-        lst = [ os.path.splitext(os.path.basename(t))[0] for t in glob.glob(os.path.join(self.path, self.pattern)) ]
+        lst = [os.path.splitext(os.path.basename(t))[0] for t in glob.glob(os.path.join(self.path, self.pattern))]
         if lst:
             # Some tests are long and are better to be started earlier,
             # so pop them up while sorting the list
@@ -201,16 +200,16 @@ class BoostTestSuite(UnitTestSuite):
 
     def __init__(self, path, cfg):
         super().__init__(path, cfg)
-        self._cases_cache = { 'name': None, 'cases': [] }
+        self._cases_cache = {'name': None, 'cases': []}
 
     def create_test(self, shortname, args, suite, mode, options):
         if options.parallel_cases and (shortname not in self.no_parallel_cases):
             if self._cases_cache['name'] != shortname:
-                cases = subprocess.run([ os.path.join("build", mode, "test", suite.name, shortname), '--list_content' ],
-                        stdout=subprocess.PIPE,
-                        stderr=subprocess.PIPE,
-                        check=True, universal_newlines=True).stderr
-                case_list = [ case[:-1] for case in cases.splitlines() if case.endswith('*')]
+                cases = subprocess.run([os.path.join("build", mode, "test", suite.name, shortname), '--list_content'],
+                                       stdout=subprocess.PIPE,
+                                       stderr=subprocess.PIPE,
+                                       check=True, universal_newlines=True).stderr
+                case_list = [case[:-1] for case in cases.splitlines() if case.endswith('*')]
                 self._cases_cache['name'] = shortname
                 self._cases_cache['cases'] = case_list
 
@@ -243,6 +242,7 @@ def add_test(self, shortname, mode, options):
     def pattern(self):
         return "*_test.cql"
 
+
 class RunTestSuite(TestSuite):
     """TestSuite for test directory with a 'run' script """
 
@@ -289,8 +289,10 @@ def check_log(self, trim):
 
 
 class UnitTest(Test):
-    standard_args = shlex.split("--overprovisioned --unsafe-bypass-fsync 1 --kernel-page-cache 1 --blocked-reactor-notify-ms 2000000 --collectd 0"
-                                " --max-networking-io-control-blocks=100")
+    standard_args = shlex.split("--overprovisioned --unsafe-bypass-fsync 1 "
+                                "--kernel-page-cache 1 "
+                                "--blocked-reactor-notify-ms 2000000 --collectd 0 "
+                                "--max-networking-io-control-blocks=100 ")
 
     def __init__(self, test_no, shortname, args, suite, mode, options):
         super().__init__(test_no, shortname, suite, mode, options)
@@ -426,6 +428,7 @@ def print_summary(self):
         if self.is_equal_result is False:
             print_unidiff(self.result, self.reject)
 
+
 class RunTest(Test):
     """Run tests in a directory started by a run script"""
 
@@ -452,6 +455,7 @@ async def run(self, options):
         logging.info("Test #%d %s", self.id, "succeeded" if self.success else "failed ")
         return self
 
+
 class TabularConsoleOutput:
     """Print test progress to the console"""
 
@@ -524,19 +528,21 @@ def report_error(error):
         ]
         try:
             log.write("=== TEST.PY STARTING TEST #{} ===\n".format(test.id).encode(encoding="UTF-8"))
-            log.write("export UBSAN_OPTIONS='{}'\n".format(":".join(filter(None, UBSAN_OPTIONS))).encode(encoding="UTF-8"))
-            log.write("export ASAN_OPTIONS='{}'\n".format(":".join(filter(None, ASAN_OPTIONS))).encode(encoding="UTF-8"))
+            log.write("export UBSAN_OPTIONS='{}'\n".format(
+                ":".join(filter(None, UBSAN_OPTIONS))).encode(encoding="UTF-8"))
+            log.write("export ASAN_OPTIONS='{}'\n".format(
+                ":".join(filter(None, ASAN_OPTIONS))).encode(encoding="UTF-8"))
             log.write("{} {}\n".format(test.path, " ".join(test.args)).encode(encoding="UTF-8"))
             log.write("=== TEST.PY TEST OUTPUT ===\n".format(test.id).encode(encoding="UTF-8"))
-            log.flush();
+            log.flush()
             test.time_start = time.time()
             test.time_end = 0
 
             path = test.path
             args = test.args
             if options.cpus:
                 path = 'taskset'
-                args = [ '-c', options.cpus, test.path, *test.args ]
+                args = ['-c', options.cpus, test.path, *test.args]
             process = await asyncio.create_subprocess_exec(
                 path, *args,
                 stderr=log,
@@ -638,14 +644,17 @@ def parse_cmd_line():
     parser.add_argument('--no-parallel-cases', dest="parallel_cases", action="store_false", default=True,
                         help="Do not run individual test cases in parallel")
     parser.add_argument('--cpus', action="store",
-                        help="Run the tests on those CPUs only (in taskset acceptible format). Consider using --jobs too")
+                        help="Run the tests on those CPUs only (in taskset"
+                        " acceptable format). Consider using --jobs too")
     args = parser.parse_args()
 
     if not args.jobs:
         if not args.cpus:
             nr_cpus = multiprocessing.cpu_count()
         else:
-            nr_cpus = int(subprocess.check_output(['taskset', '-c', args.cpus, 'python', '-c', 'import os; print(len(os.sched_getaffinity(0)))']))
+            nr_cpus = int(subprocess.check_output(
+                ['taskset', '-c', args.cpus, 'python', '-c',
+                 'import os; print(len(os.sched_getaffinity(0)))']))
 
         cpus_per_test_job = 1
         sysmem = os.sysconf('SC_PAGE_SIZE') * os.sysconf('SC_PHYS_PAGES')
@@ -661,8 +670,9 @@ def parse_cmd_line():
             out = subprocess.Popen(['ninja', 'mode_list'], stdout=subprocess.PIPE).communicate()[0].decode()
             # [1/1] List configured modes
             # debug release dev
-            args.modes= re.sub(r'.* List configured modes\n(.*)\n', r'\1', out, 1, re.DOTALL).split("\n")[-1].split(' ')
-        except Exception as e:
+            args.modes = re.sub(r'.* List configured modes\n(.*)\n', r'\1',
+                                out, 1, re.DOTALL).split("\n")[-1].split(' ')
+        except Exception:
             print(palette.fail("Failed to read output of `ninja mode_list`: please run ./configure.py first"))
             raise
 
@@ -686,7 +696,7 @@ def prepare_dir(dirname, pattern):
         out = subprocess.Popen(['ninja', 'unit_test_list'], stdout=subprocess.PIPE).communicate()[0].decode()
         # [1/1] List configured unit tests
         args.tests = set(re.sub(r'.* List configured unit tests\n(.*)\n', r'\1', out, 1, re.DOTALL).split("\n"))
-    except Exception as e:
+    except Exception:
         print(palette.fail("Failed to read output of `ninja unit_test_list`: please run ./configure.py first"))
         raise
 
@@ -829,6 +839,7 @@ def write_junit_report(tmpdir, mode):
     with open(junit_filename, "w") as f:
         ET.ElementTree(xml_results).write(f, encoding="unicode")
 
+
 def write_consolidated_boost_junit_xml(tmpdir, mode):
     xml = ET.Element("TestLog")
     for suite in TestSuite.suites.values():
@@ -841,6 +852,7 @@ def write_consolidated_boost_junit_xml(tmpdir, mode):
     et = ET.ElementTree(xml)
     et.write(f'{tmpdir}/{mode}/xml/boost.xunit.xml', encoding='unicode')
 
+
 def open_log(tmpdir):
     pathlib.Path(tmpdir).mkdir(parents=True, exist_ok=True)
     logging.basicConfig(