diff --git a/tests/http/testenv/curl.py b/tests/http/testenv/curl.py
index 22a8ffb6eb..98c1bd4ab8 100644
--- a/tests/http/testenv/curl.py
+++ b/tests/http/testenv/curl.py
@@ -162,7 +162,7 @@ class ExecResult:
     def check_exit_code(self, code: int):
         assert self.exit_code == code, \
             f'expected exit code {code}, '\
-            'got {self.exit_code}\n{self._dump_logs()}'
+            f'got {self.exit_code}\n{self._dump_logs()}'
 
     def check_exit_code_not(self, code: int):
         assert self.exit_code != code, \