diff --git a/tests/test_selector.py b/tests/test_selector.py
index 85527bba9..1b5f3f018 100644
--- a/tests/test_selector.py
+++ b/tests/test_selector.py
@@ -80,10 +80,10 @@ class SelectorTestCase(unittest.TestCase):
         meta = (
             '<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">'
         )
-        head = "<head>" + meta + "</head>"
+        head = f"<head>{meta}</head>"
         body_content = '<span id="blank">\xa3</span>'
-        body = "<body>" + body_content + "</body>"
-        html = "<html>" + head + body + "</html>"
+        body = f"<body>{body_content}</body>"
+        html = f"<html>{head}{body}</html>"
         encoding = "utf-8"
         html_utf8 = html.encode(encoding)
 
