diff --git a/src/main.py b/src/main.py
index 1928875..1d43090 100644
--- a/src/main.py
+++ b/src/main.py
@@ -10,18 +10,22 @@
 from src import interp
 
 
+def run_file(file, log_level=log.NORMAL):
+    log.set_default_log_level(log_level)
+    ast = oldparse.parse_file(file)
+    if not ast:
+        return 1
+    interp.run_ast(ast)
+    return 0
+
+
 def main():
     args = sys.argv
     log_level = os.getenv("NEWLANG_LOG_LEVEL")
     if len(args) != 2:
         print("Usage: main.py FILENAME")
         return 1
-    log.set_default_log_level(log_level)
-    ast = oldparse.parse_file(args[1])
-    if not ast:
-        return 1
-    interp.run_ast(ast)
-    return 0
+    return run_file(args[1], log_level)
 
 
 def unexpected_exit():