fix

Author: Pierre-Sassoulas

src/_pytest/pytester.py

@@ -547,7 +547,7 @@ def __init__(
 
     def __repr__(self) -> str:
         return (
-            f"<RunResult ret={self.ret} "
+            f"<RunResult ret={self.ret!s} "
             f"len(stdout.lines)={len(self.stdout.lines)} "
             f"len(stderr.lines)={len(self.stderr.lines)} "
             f"duration={self.duration:.2f}s>"