Tests: switched to using f-strings.

Previously, it was necessary to support older versions of Python for
compatibility.  F-strings were released in Python 3.6.  Python 3.5 was
marked as unsupported by the end of 2020, so now it's possible to start
using f-strings safely for better readability and performance.

1 files changed, 39 insertions, 45 deletions

diff --git a/test/conftest.py b/test/conftest.py
index b4951273..8944c6b3 100644
--- a/test/conftest.py
+++ b/test/conftest.py
@@ -107,7 +107,7 @@ def pytest_configure(config):
     option.current_dir = os.path.abspath(
         os.path.join(os.path.dirname(__file__), os.pardir)
     )
-    option.test_dir = option.current_dir + '/test'
+    option.test_dir = f'{option.current_dir}/test'
     option.architecture = platform.architecture()[0]
     option.system = platform.system()
 
@@ -148,8 +148,8 @@ def pytest_generate_tests(metafunc):
 
         for version in versions:
             option.generated_tests[
-                metafunc.function.__name__ + '[{}]'.format(version)
-            ] = (type + ' ' + version)
+                f'{metafunc.function.__name__} [{version}]'
+            ] = f'{type} {version}'
 
     # take available module from option and generate tests for each version
 
@@ -161,18 +161,17 @@ def pytest_generate_tests(metafunc):
                 generate_tests(available_versions)
 
             elif prereq_version == 'any':
-                option.generated_tests[metafunc.function.__name__] = (
-                    type + ' ' + available_versions[0]
-                )
+                option.generated_tests[
+                    metafunc.function.__name__
+                ] = f'{type} {available_versions[0]}'
             elif callable(prereq_version):
                 generate_tests(list(filter(prereq_version, available_versions)))
 
             else:
                 raise ValueError(
-                    """
-Unexpected prerequisite version "%s" for module "%s" in %s.
-'all', 'any' or callable expected."""
-                    % (str(prereq_version), module, str(cls))
+                    f'''
+Unexpected prerequisite version "{prereq_version}" for module "{module}" in
+{cls}. 'all', 'any' or callable expected.'''
                 )
 
 
@@ -225,7 +224,7 @@ def pytest_sessionstart(session):
     check_isolation()
     check_unix_abstract()
 
-    _clear_conf(unit['temp_dir'] + '/control.unit.sock')
+    _clear_conf(f'{unit["temp_dir"]}/control.unit.sock')
 
     unit_stop()
 
@@ -244,7 +243,7 @@ def pytest_runtest_makereport(item, call):
     # set a report attribute for each phase of a call, which can
     # be "setup", "call", "teardown"
 
-    setattr(item, "rep_" + rep.when, rep)
+    setattr(item, f'rep_{rep.when}', rep)
 
 
 @pytest.fixture(scope='class', autouse=True)
@@ -264,7 +263,7 @@ def check_prerequisites(request):
             missed.append(module)
 
     if missed:
-        pytest.skip('Unit has no ' + ', '.join(missed) + ' module(s)')
+        pytest.skip(f'Unit has no {", ".join(missed)} module(s)')
 
     # check features
 
@@ -278,7 +277,7 @@ def check_prerequisites(request):
             missed.append(feature)
 
     if missed:
-        pytest.skip(', '.join(missed) + ' feature(s) not supported')
+        pytest.skip(f'{", ".join(missed)} feature(s) not supported')
 
 
 @pytest.fixture(autouse=True)
@@ -316,7 +315,7 @@ def run(request):
     # clean temp_dir before the next test
 
     if not option.restart:
-        _clear_conf(unit['temp_dir'] + '/control.unit.sock', log=log)
+        _clear_conf(f'{unit["temp_dir"]}/control.unit.sock', log=log)
 
         if is_findmnt and not waitforunmount(unit['temp_dir'], timeout=600):
             exit('Could not unmount some filesystems in tmp dir.')
@@ -374,8 +373,8 @@ def unit_run(state_dir=None):
     if not option.restart and 'unitd' in unit_instance:
         return unit_instance
 
-    build_dir = option.current_dir + '/build'
-    unitd = build_dir + '/unitd'
+    build_dir = f'{option.current_dir}/build'
+    unitd = f'{build_dir}/unitd'
 
     if not os.path.isfile(unitd):
         exit('Could not find unit')
@@ -386,10 +385,12 @@ def unit_run(state_dir=None):
     if oct(stat.S_IMODE(os.stat(build_dir).st_mode)) != '0o777':
         public_dir(build_dir)
 
-    state = temp_dir + '/state' if state_dir is None else state_dir
+    state = f'{temp_dir}/state' if state_dir is None else state_dir
     if not os.path.isdir(state):
         os.mkdir(state)
 
+    control_sock = f'{temp_dir}/control.unit.sock'
+
     unitd_args = [
         unitd,
         '--no-daemon',
@@ -398,11 +399,11 @@ def unit_run(state_dir=None):
         '--libstatedir',
         state,
         '--pid',
-        temp_dir + '/unit.pid',
+        f'{temp_dir}/unit.pid',
         '--log',
-        temp_dir + '/unit.log',
+        f'{temp_dir}/unit.log',
         '--control',
-        'unix:' + temp_dir + '/control.unit.sock',
+        f'unix:{temp_dir}/control.unit.sock',
         '--tmpdir',
         temp_dir,
     ]
@@ -410,26 +411,26 @@ def unit_run(state_dir=None):
     if option.user:
         unitd_args.extend(['--user', option.user])
 
-    with open(temp_dir + '/unit.log', 'w') as log:
+    with open(f'{temp_dir}/unit.log', 'w') as log:
         unit_instance['process'] = subprocess.Popen(unitd_args, stderr=log)
 
     Log.temp_dir = temp_dir
 
-    if not waitforfiles(temp_dir + '/control.unit.sock'):
+    if not waitforfiles(control_sock):
         _print_log()
         exit('Could not start unit')
 
     unit_instance['temp_dir'] = temp_dir
-    unit_instance['control_sock'] = temp_dir + '/control.unit.sock'
+    unit_instance['control_sock'] = control_sock
     unit_instance['unitd'] = unitd
 
     option.temp_dir = temp_dir
 
-    with open(temp_dir + '/unit.pid', 'r') as f:
+    with open(f'{temp_dir}/unit.pid', 'r') as f:
         unit_instance['pid'] = f.read().rstrip()
 
     if state_dir is None:
-        _clear_conf(unit_instance['temp_dir'] + '/control.unit.sock')
+        _clear_conf(control_sock)
 
     _fds_info['main']['fds'] = _count_fds(unit_instance['pid'])
 
@@ -473,7 +474,7 @@ def unit_stop():
     try:
         retcode = p.wait(15)
         if retcode:
-            return 'Child process terminated with code ' + str(retcode)
+            return f'Child process terminated with code {retcode}'
 
     except KeyboardInterrupt:
         p.kill()
@@ -518,7 +519,7 @@ def _check_alerts(*, log=None):
 def _print_log(log=None):
     path = Log.get_path()
 
-    print('Path to unit.log:\n' + path + '\n')
+    print(f'Path to unit.log:\n{path}\n')
 
     if option.print_log:
         os.set_blocking(sys.stdout.fileno(), True)
@@ -551,11 +552,11 @@ def _clear_conf(sock, *, log=None):
         ).keys()
 
     except json.JSONDecodeError:
-        pytest.fail('Can\'t parse certificates list.')
+        pytest.fail("Can't parse certificates list.")
 
     for cert in certs:
         resp = http.delete(
-            url='/certificates/' + cert,
+            url=f'/certificates/{cert}',
             sock_type='unix',
             addr=sock,
         )['body']
@@ -595,17 +596,14 @@ def _check_processes():
     out = [
         l
         for l in out
-        if re.search(router_pid + r'\s+' + unit_pid + r'.*unit: router', l)
-        is None
+        if re.search(fr'{router_pid}\s+{unit_pid}.*unit: router', l) is None
     ]
     assert len(out) == 1, 'one router'
 
     out = [
         l
         for l in out
-        if re.search(
-            controller_pid + r'\s+' + unit_pid + r'.*unit: controller', l
-        )
+        if re.search(fr'{controller_pid}\s+{unit_pid}.*unit: controller', l)
         is None
     ]
     assert len(out) == 0, 'one controller'
@@ -646,18 +644,16 @@ def _check_fds(*, log=None):
             ps['fds'] += fds_diff
 
             if not option.restart:
-                assert ps['pid'] == ps_pid, 'same pid %s' % name
+                assert ps['pid'] == ps_pid, f'same pid {name}'
 
-            assert fds_diff <= option.fds_threshold, (
-                'descriptors leak %s' % name
-            )
+            assert fds_diff <= option.fds_threshold, f'descriptors leak {name}'
 
         else:
             ps['fds'] = _count_fds(ps['pid'])
 
 
 def _count_fds(pid):
-    procfile = '/proc/%s/fd' % pid
+    procfile = f'/proc/{pid}/fd'
     if os.path.isdir(procfile):
         return len(os.listdir(procfile))
 
@@ -712,14 +708,12 @@ def stop_processes():
 
 def pid_by_name(name):
     output = subprocess.check_output(['ps', 'ax', '-O', 'ppid']).decode()
-    m = re.search(
-        r'\s*(\d+)\s*' + str(unit_instance['pid']) + r'.*' + name, output
-    )
+    m = re.search(fr'\s*(\d+)\s*{unit_instance["pid"]}.*{name}', output)
     return None if m is None else m.group(1)
 
 
 def find_proc(name, ps_output):
-    return re.findall(str(unit_instance['pid']) + r'.*' + name, ps_output)
+    return re.findall(f'{unit_instance["pid"]}.*{name}', ps_output)
 
 
 @pytest.fixture()
@@ -762,7 +756,7 @@ def unit_pid(request):
 
 def pytest_sessionfinish(session):
     if not option.restart and option.save_log:
-        print('Path to unit.log:\n' + Log.get_path() + '\n')
+        print(f'Path to unit.log:\n{Log.get_path()}\n')
 
     option.restart = True