Add removeprefix to strutils for older python versions & fix test on windows

Author: theartful

boltons/strutils.py

@@ -57,7 +57,7 @@
            'iter_splitlines', 'indent', 'escape_shell_args',
            'args2cmd', 'args2sh', 'parse_int_list', 'format_int_list',
            'complement_int_list', 'int_ranges_from_int_list', 'MultiReplace',
-           'multi_replace', 'unwrap_text']
+           'multi_replace', 'unwrap_text', 'removeprefix']
 
 
 _punct_ws_str = string.punctuation + string.whitespace
@@ -1273,3 +1273,17 @@ def unwrap_text(text, ending='\n\n'):
     if ending is None:
         return all_grafs
     return ending.join(all_grafs)
+
+def removeprefix(text: str, prefix: str) -> str:
+    r"""
+    Remove `prefix` from start of `text` if present.
+
+    Backport of `str.removeprefix` for Python versions less than 3.9.
+
+    Args:
+        text: A string to remove the prefix from.
+        prefix: The string to remove from the beginning of `text`.
+    """
+    if text.startswith(prefix):
+        return text[len(prefix):]
+    return text

tests/test_fileutils.py

@@ -6,6 +6,7 @@
 
 from boltons import fileutils
 from boltons.fileutils import FilePerms, iter_find_files
+from boltons.strutils import removeprefix
 
 
 # Directory of boltons source files (not ending with '/').
@@ -32,13 +33,13 @@ def test_fileperms():
 
 def test_iter_find_files():
     def _to_baseless_list(paths):
-        return [p.removeprefix(BOLTONS_PATH) for p in paths]
+        return [removeprefix(p, BOLTONS_PATH).lstrip(os.path.sep) for p in paths]
 
-    assert '/fileutils.py' in _to_baseless_list(iter_find_files(BOLTONS_PATH, patterns=['*.py']))
+    assert 'fileutils.py' in _to_baseless_list(iter_find_files(BOLTONS_PATH, patterns=['*.py']))
 
     boltons_parent = os.path.dirname(BOLTONS_PATH)
-    assert '/fileutils.py' in _to_baseless_list(iter_find_files(boltons_parent, patterns=['*.py']))
-    assert '/fileutils.py' not in _to_baseless_list(iter_find_files(boltons_parent, patterns=['*.py'], max_depth=0))
+    assert 'fileutils.py' in _to_baseless_list(iter_find_files(boltons_parent, patterns=['*.py']))
+    assert 'fileutils.py' not in _to_baseless_list(iter_find_files(boltons_parent, patterns=['*.py'], max_depth=0))
 
 
 def test_rotate_file_no_rotation(tmp_path):