Add FreeBSD fix for locale failure

FreeBSD seems to throw an OSError when locale.strxfrm is given 'Å',
which is surprising behavior. Well, maybe not, considering how many bugs
I have found with FreeBSD's implementation of locale over the course of
natsort development.

Anyway, we just ignore any input that causes locale.strxfrm to barf in
our tests.

2 files changed, 17 insertions, 2 deletions

diff --git a/natsort/compat/fake_fastnumbers.py b/natsort/compat/fake_fastnumbers.py
index cb1c900..430345a 100644
--- a/natsort/compat/fake_fastnumbers.py
+++ b/natsort/compat/fake_fastnumbers.py
@@ -55,7 +55,7 @@ def fast_float(
         String to attempt to convert to a float.
     key : callable
         Single-argument function to apply to *x* if conversion fails.
-    nan : object
+    nan : float
         Value to return instead of NaN if NaN would be returned.
 
     Returns
diff --git a/tests/test_string_component_transform_factory.py b/tests/test_string_component_transform_factory.py
index bc48d5b..40b4d34 100644
--- a/tests/test_string_component_transform_factory.py
+++ b/tests/test_string_component_transform_factory.py
@@ -5,7 +5,7 @@ from functools import partial
 from typing import Any, Callable, FrozenSet, Union
 
 import pytest
-from hypothesis import example, given
+from hypothesis import assume, example, given
 from hypothesis.strategies import floats, integers, text
 from natsort.compat.fastnumbers import try_float, try_int
 from natsort.compat.locale import get_strxfrm
@@ -32,6 +32,20 @@ def no_null(x: str) -> bool:
     return "\0" not in x
 
 
+def input_is_ok_with_locale(x: str) -> bool:
+    """Ensure this input won't cause locale.strxfrm to barf"""
+    # On FreeBSD, locale.strxfrm raises an OSError on input like 'Å'.
+    # You read that right - an *OSError* for invalid input.
+    # We cannot really fix that, so we just filter out any value
+    # that could cause locale.strxfrm to barf with this function.
+    try:
+        get_strxfrm()(x)
+    except OSError:
+        return False
+    else:
+        return True
+
+
 @pytest.mark.parametrize(
     "alg, example_func",
     [
@@ -77,6 +91,7 @@ def test_string_component_transform_factory(
 ) -> None:
     string_component_transform_func = string_component_transform_factory(alg)
     x = str(x)
+    assume(input_is_ok_with_locale(x))  # handle broken locale lib on BSD.
     try:
         assert list(string_component_transform_func(x)) == list(example_func(x))
     except ValueError as e:  # handle broken locale lib on BSD.