Add presort to natsorted and friends

This will sort the collection as strings before sorting with the natsort
algorithm. This ensures that strings that are different but represent
the same numerical value get sorted independent of input order.

1 files changed, 7 insertions, 0 deletions

diff --git a/tests/test_os_sorted.py b/tests/test_os_sorted.py
index f714437..c29c110 100644
--- a/tests/test_os_sorted.py
+++ b/tests/test_os_sorted.py
@@ -47,6 +47,13 @@ def test_os_sorted_key() -> None:
     assert result == expected
 
 
+def test_os_sorted_can_presort() -> None:
+    given = ["a1", "a01"]
+    expected = ["a01", "a1"]
+    result = natsort.os_sorted(given, presort=True)
+    assert result == expected
+
+
 # The following is a master list of things that might give trouble
 # when sorting like the file explorer.
 given_characters = [