diff --git a/mesonbuild/mtest.py b/mesonbuild/mtest.py
index f877ec8ec..36c4da982 100644
--- a/mesonbuild/mtest.py
+++ b/mesonbuild/mtest.py
@@ -430,7 +430,7 @@ class TAPParser:
             if not line:
                 return
 
-            yield self.Error('unexpected input at line {}'.format((self.lineno,)))
+            yield self.Error(f'unexpected input at line {self.lineno}')
         else:
             # end of file
             if self.state == self._YAML: