diff --git a/testsuite/python_support/utils.py b/testsuite/python_support/utils.py
index 6d52d3bd9..572bc8564 100644
--- a/testsuite/python_support/utils.py
+++ b/testsuite/python_support/utils.py
@@ -474,7 +474,7 @@ def fmt_str_list(strings: list[str]) -> str:
             lib_path = m.dirs.build_lib_dir("relocatable", "dev")
             os_specific_options.extend(
                 [
-                    f"--native-compiler-options=-I{m.dirs.build_dir("src")}",
+                    f"--native-compiler-options=-I{m.dirs.build_dir('src')}",
                     f"--native-compiler-options=-L{lib_path}",
                 ]
             )