support case where no previous tests have been found

pytest_abra/cli.py

@@ -29,6 +29,8 @@ def run():
 
     session_id = "test-" + get_datetime_string()
     if args.resume:
+        latest_session_id = DirManager.get_latest_session_id(args.output_dir)
+        if latest_session_id:
             session_id = DirManager.get_latest_session_id(args.output_dir)
 
     # ------------------------------- setup logging ------------------------------ #

pytest_abra/dir_manager.py

@@ -1,4 +1,5 @@
 from pathlib import Path
+from typing import Optional
 
 from dotenv import dotenv_values
 
@@ -78,8 +79,11 @@ class DirManager:
         return config
 
     @staticmethod
-    def get_latest_session_id(output_dir: Path) -> str:
+    def get_latest_session_id(output_dir: Path) -> Optional[str]:
         """returns the name of the newest dir inside of output_dir"""
         all_dirs = [d for d in output_dir.iterdir() if d.is_dir()]
+        if all_dirs:
             newest_dir: Path = max(all_dirs, key=lambda x: x.stat().st_ctime)
             return newest_dir.name
+        else:
+            return None