diff --git a/cpp/test/run_test.py b/cpp/test/run_test.py
index 78fd662..90b4f7d 100644
--- a/cpp/test/run_test.py
+++ b/cpp/test/run_test.py
@@ -113,7 +113,7 @@ def __init__(self, carver):
 
     def run(self, input_rel_path):
         cwd = os.getcwd()
-        completed = subprocess.run([self.carver, input_rel_path], capture_output=True, text=True)
+        completed = subprocess.run([self.carver, '-r=main', input_rel_path], capture_output=True, text=True)
         return completed.stdout if completed.stdout != None else completed.stderr
 
     def output(self, input_rel_path):