diff --git a/cheroot/server.py b/cheroot/server.py
index bceeb2c95a..cd1cdc75d9 100644
--- a/cheroot/server.py
+++ b/cheroot/server.py
@@ -209,7 +209,11 @@ def __call__(self, rfile, hdict=None):  # noqa: C901  # FIXME
             if not line.endswith(CRLF):
                 raise ValueError('HTTP requires CRLF terminators')
 
-            if line[0] in (SPACE, TAB):
+            if line[:1] in (SPACE, TAB):
+                # NOTE: `type(line[0]) is int` and `type(line[:1]) is bytes`.
+                # NOTE: The former causes a the following warning:
+                # NOTE: `BytesWarning('Comparison between bytes and int')`
+                # NOTE: The latter is equivalent and does not.
                 # It's a continuation line.
                 v = line.strip()
             else:
diff --git a/cheroot/test/test_conn.py b/cheroot/test/test_conn.py
index b5e9c418f9..38a6245715 100644
--- a/cheroot/test/test_conn.py
+++ b/cheroot/test/test_conn.py
@@ -53,7 +53,8 @@ def upload(req, resp):
                 "'POST' != request.method %r" %
                 req.environ['REQUEST_METHOD'],
             )
-        return "thanks for '%s'" % req.environ['wsgi.input'].read()
+        input_contents = req.environ['wsgi.input'].read().decode('utf-8')
+        return f"thanks for '{input_contents !s}'"
 
     def custom_204(req, resp):
         """Render response with status 204."""
@@ -917,7 +918,7 @@ def test_100_Continue(test_client):
     status_line, _actual_headers, actual_resp_body = webtest.shb(response)
     actual_status = int(status_line[:3])
     assert actual_status == 200
-    expected_resp_body = ("thanks for '%s'" % body).encode()
+    expected_resp_body = f"thanks for '{body.decode() !s}'".encode()
     assert actual_resp_body == expected_resp_body
     conn.close()
 
@@ -987,7 +988,7 @@ def test_readall_or_close(test_client, max_request_body_size):
     status_line, actual_headers, actual_resp_body = webtest.shb(response)
     actual_status = int(status_line[:3])
     assert actual_status == 200
-    expected_resp_body = ("thanks for '%s'" % body).encode()
+    expected_resp_body = f"thanks for '{body.decode() !s}'".encode()
     assert actual_resp_body == expected_resp_body
     conn.close()