Limit name byte length

bulkredditdownloader/file_name_formatter.py

@@ -59,9 +59,10 @@ class FileNameFormatter:
 
     @staticmethod
     def _limit_file_name_length(filename: str, ending: str) -> str:
-        max_length = 255 - len(ending)
-        if len(filename) > max_length:
-            filename = filename[:max_length]
+        max_length_chars = 255 - len(ending)
+        max_length_bytes = 255 - len(ending.encode('utf-8'))
+        while len(filename) > max_length_chars or len(filename.encode('utf-8')) > max_length_bytes:
+            filename = filename[:-1]
         return filename + ending
 
     def format_resource_paths(self, resources: list[Resource],

bulkredditdownloader/tests/test_file_name_formatter.py

@@ -131,10 +131,13 @@ def test_format_multiple_resources():
     ('A' * 300, '.png'),
     ('A' * 300, '_1.png'),
     ('a' * 300, '_1000.jpeg'),
+    ('😍💕✨' * 100, '_1.png'),
 ))
 def test_limit_filename_length(test_filename: str, test_ending: str):
     result = FileNameFormatter._limit_file_name_length(test_filename, test_ending)
     assert len(result) <= 255
+    assert len(result.encode('utf-8')) <= 255
+    assert isinstance(result, str)
 
 
 @pytest.mark.online