add a regression test for git ls-files parsing

This commit adds a regression test to ensure
that file-names starting with a tab-character
are properly parsed from the output of
`git ls-files`.

The test instantiates PurePosixPath-instances
to check against names in the output of
`iter_gitworktree`, because `iter_gitworktree`
explicitly creates PurePosixPath-instances in
the function `_lsfiles_line2props`.

datalad_next/iter_collections/tests/test_itergitworktree.py

@@ -1,4 +1,7 @@
-from pathlib import PurePath
+from pathlib import (
+    PurePath,
+    PurePosixPath,
+)
 from ..gitworktree import (
     GitWorktreeItem,
     GitWorktreeFileSystemItem,
@@ -72,3 +75,14 @@ def test_iter_gitworktree(existing_dataset):
             checked_untracked = True
     assert checked_tracked
     assert checked_untracked
+
+
+def test_name_starting_with_tab(existing_dataset):
+    ds = existing_dataset
+    tabbed_file_name = "\ttab.txt"
+    tabbed_name = ds.pathobj / tabbed_file_name
+    tabbed_name.write_text('name of this file starts with a tab')
+    ds.save()
+
+    iter_names = [item.name for item in iter_gitworktree(ds.pathobj)]
+    assert PurePosixPath(tabbed_file_name) in iter_names