Fix flake8 issue WPS336 (explicit str concat)

cheroot/server.py

@@ -156,7 +156,7 @@
 ASTERISK = b'*'
 FORWARD_SLASH = b'/'
 QUOTED_SLASH = b'%2F'
-QUOTED_SLASH_REGEX = re.compile(b'(?i)' + QUOTED_SLASH)
+QUOTED_SLASH_REGEX = re.compile(b''.join([b'(?i)', QUOTED_SLASH]))
 
 
 comma_separated_headers = [
@@ -467,7 +467,8 @@ def _fetch(self):
             chunk_size = line.pop(0)
             chunk_size = int(chunk_size, 16)
         except ValueError:
-            raise ValueError('Bad chunked transfer size: ' + repr(chunk_size))
+            raise ValueError('Bad chunked transfer size: {}'
+                             .format(repr(chunk_size)))
 
         if chunk_size <= 0:
             self.closed = True
@@ -822,7 +823,9 @@ def read_request_line(self):
 
             # `urlsplit()` above parses "example.com:3128" as path part of URI.
             # this is a workaround, which makes it detect netloc correctly
-            uri_split = urllib.parse.urlsplit(b'//' + uri)
+            uri_split = urllib.parse.urlsplit(
+                '//{}'.format(uri)
+                .encode('ascii'))
             _scheme, _authority, _path, _qs, _fragment = uri_split
             _port = EMPTY
             try:
@@ -1037,8 +1040,9 @@ def read_request_headers(self):
             # Don't use simple_response here, because it emits headers
             # we don't want. See
             # https://github.com/cherrypy/cherrypy/issues/951
-            msg = self.server.protocol.encode('ascii')
-            msg += b' 100 Continue\r\n\r\n'
+            msg = '{} {}'.format(self.server.protocol,
+                '100 Continue\r\n\r\n') \
+                .encode('ascii')
             try:
                 self.conn.wfile.write(msg)
             except socket.error as ex:
@@ -1499,7 +1503,7 @@ class HTTPServer:
     timeout = 10
     """The timeout in seconds for accepted connections (default 10)."""
 
-    version = 'Cheroot/' + __version__
+    version = 'Cheroot/{}'.format(__version__)
     """A version string for the HTTPServer."""
 
     software = None
@@ -1805,7 +1809,7 @@ def error_log(self, msg='', level=20, traceback=False):
             traceback (bool): add traceback to output or not
         """
         # Override this in subclasses as desired
-        sys.stderr.write(msg + '\n')
+        sys.stderr.write('{}\n'.format(msg))
         sys.stderr.flush()
         if traceback:
             tblines = traceback_.format_exc()

cheroot/test/test_conn.py

@@ -838,7 +838,8 @@ def test_Chunked_Encoding(test_client):
 
     # Try a chunked request that exceeds server.max_request_body_size.
     # Note that the delimiters and trailer are included.
-    body = b'3e3\r\n' + (b'x' * 995) + b'\r\n0\r\n\r\n'
+    body = '{}{}{}'.format('3e3\r\n', 'x' * 995, '\r\n0\r\n\r\n') \
+        .encode('ascii')
     conn.putrequest('POST', '/upload', skip_host=True)
     conn.putheader('Host', conn.host)
     conn.putheader('Transfer-Encoding', 'chunked')
@@ -971,8 +972,8 @@ def test_No_CRLF(test_client, invalid_terminator):
     # Initialize a persistent HTTP connection
     conn = test_client.get_connection()
 
-    # (b'%s' % b'') is not supported in Python 3.4, so just use +
-    conn.send(b'GET /hello HTTP/1.1' + invalid_terminator)
+    conn.send('GET /hello HTTP/1.1{}'.format(invalid_terminator)
+                                     .encode('ascii'))
     response = conn.response_class(conn.sock, method='GET')
     response.begin()
     actual_resp_body = response.read()

cheroot/test/test_ssl.py

@@ -189,7 +189,7 @@ def test_ssl_adapters(
     )
 
     resp = requests.get(
-        'https://' + interface + ':' + str(port) + '/',
+        'https://{}:{}/'.format(interface, port),
         verify=tls_ca_certificate_pem_path,
     )
 
@@ -274,7 +274,7 @@ def test_tls_client_auth(
 
         make_https_request = functools.partial(
             requests.get,
-            'https://' + interface + ':' + str(port) + '/',
+            'https://{}:{}/'.format(interface, port),
 
             # Server TLS certificate verification:
             verify=tls_ca_certificate_pem_path,
@@ -482,7 +482,7 @@ def test_http_over_https_error(
         expect_fallback_response_over_plain_http = False
     if expect_fallback_response_over_plain_http:
         resp = requests.get(
-            'http://' + fqdn + ':' + str(port) + '/',
+            'http://{}:{}/'.format(fqdn, port),
         )
         assert resp.status_code == 400
         assert resp.text == (
@@ -493,7 +493,7 @@ def test_http_over_https_error(
 
     with pytest.raises(requests.exceptions.ConnectionError) as ssl_err:
         requests.get(  # FIXME: make stdlib ssl behave like PyOpenSSL
-            'http://' + fqdn + ':' + str(port) + '/',
+            'http://{}:{}/'.format(fqdn, port),
         )
 
     if IS_LINUX:

cheroot/workers/threadpool.py

@@ -176,7 +176,7 @@ def start(self):
         for i in range(self.min):
             self._threads.append(WorkerThread(self.server))
         for worker in self._threads:
-            worker.setName('CP Server ' + worker.getName())
+            worker.setName('CP Server {}'.format(worker.getName()))
             worker.start()
         for worker in self._threads:
             while not worker.ready:
@@ -223,7 +223,7 @@ def grow(self, amount):
 
     def _spawn_worker(self):
         worker = WorkerThread(self.server)
-        worker.setName('CP Server ' + worker.getName())
+        worker.setName('CP Server {}'.format(worker.getName()))
         worker.start()
         return worker
 

cheroot/wsgi.py

@@ -300,7 +300,7 @@ def get_environ(self):
 
         # Request headers
         env.update(
-            ('HTTP_' + bton(k).upper().replace('-', '_'), bton(v))
+            ('HTTP_%s' % (bton(k).upper().replace('-', '_')), bton(v))
             for k, v in req.inheaders.items()
         )
 
@@ -409,7 +409,7 @@ def __call__(self, environ, start_response):
         path = environ['PATH_INFO'] or '/'
         for p, app in self.apps:
             # The apps list should be sorted by length, descending.
-            if path.startswith(p + '/') or path == p:
+            if path.startswith('%s/' % (p)) or path == p:
                 environ = environ.copy()
                 environ['SCRIPT_NAME'] = environ.get('SCRIPT_NAME', '') + p
                 environ['PATH_INFO'] = path[len(p):]