RustPython
diff --git a/Lib/test/test_locale.py b/Lib/test/test_locale.py
@@ -381,6 +381,8 @@ def setUp(self):
         is_emscripten or is_wasi,
         "musl libc issue on Emscripten/WASI, bpo-46390"
     )
+    # TODO: RUSTPYTHON", strcoll has not been implemented
+    @unittest.expectedFailure
     def test_strcoll_with_diacritic(self):
         self.assertLess(locale.strcoll('à', 'b'), 0)
 
@@ -390,6 +392,8 @@ def test_strcoll_with_diacritic(self):
         is_emscripten or is_wasi,
         "musl libc issue on Emscripten/WASI, bpo-46390"
     )
+    # TODO: RUSTPYTHON", strxfrm has not been implemented
+    @unittest.expectedFailure
     def test_strxfrm_with_diacritic(self):
         self.assertLess(locale.strxfrm('à'), locale.strxfrm('b'))
 
@@ -506,8 +510,6 @@ def test_japanese(self):
 
 
 class TestMiscellaneous(unittest.TestCase):
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_defaults_UTF8(self):
         # Issue #18378: on (at least) macOS setting LC_CTYPE to "UTF-8" is
         # valid. Furthermore LC_CTYPE=UTF is used by the UTF-8 locale coercing
@@ -544,6 +546,10 @@ def test_defaults_UTF8(self):
 
             if orig_getlocale is not None:
                 _locale._getdefaultlocale = orig_getlocale
+
+    # TODO: RUSTPYTHON                
+    if sys.platform == "win32":
+        test_defaults_UTF8 = unittest.expectedFailure(test_defaults_UTF8)
 
     def test_getencoding(self):
         # Invoke getencoding to make sure it does not cause exceptions.
@@ -565,8 +571,6 @@ def test_strcoll_3303(self):
         self.assertRaises(TypeError, locale.strcoll, "a", None)
         self.assertRaises(TypeError, locale.strcoll, b"a", None)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_setlocale_category(self):
         locale.setlocale(locale.LC_ALL)
         locale.setlocale(locale.LC_TIME)
@@ -577,6 +581,10 @@ def test_setlocale_category(self):
 
         # crasher from bug #7419
         self.assertRaises(locale.Error, locale.setlocale, 12345)
+
+    # TODO: RUSTPYTHON
+    if sys.platform == "win32":
+        test_setlocale_category = unittest.expectedFailure(test_setlocale_category)
 
     def test_getsetlocale_issue1813(self):
         # Issue #1813: setting and getting the locale under a Turkish locale

diff --git a/Lib/test/test_types.py b/Lib/test/test_types.py
@@ -403,6 +403,7 @@ def test_float__format__locale(self):
             self.assertEqual(locale.format_string('%g', x, grouping=True), format(x, 'n'))
             self.assertEqual(locale.format_string('%.10g', x, grouping=True), format(x, '.10n'))
 
+    @unittest.skip("TODO: RustPython format code n is not integrated with locale")
     @run_with_locale('LC_NUMERIC', 'en_US.UTF8')
     def test_int__format__locale(self):
         # test locale support for __format__ code 'n' for integers

diff --git a/stdlib/src/lib.rs b/stdlib/src/lib.rs
@@ -15,6 +15,7 @@ mod dis;
 mod gc;
 mod hashlib;
 mod json;
+mod locale;
 mod math;
 #[cfg(unix)]
 mod mmap;
@@ -159,5 +160,9 @@ pub fn get_module_inits() -> impl Iterator<Item = (Cow<'static, str>, StdlibInit
         {
             "_uuid" => uuid::make_module,
         }
+        #[cfg(all(unix, not(any(target_os = "ios", target_os = "android"))))]
+        {
+            "_locale" => locale::make_module,
+        }
     }
 }
diff --git a/stdlib/src/locale.rs b/stdlib/src/locale.rs
@@ -0,0 +1,151 @@
+#[cfg(all(unix, not(any(target_os = "ios", target_os = "android"))))]
+pub(crate) use _locale::make_module;
+
+#[cfg(all(unix, not(any(target_os = "ios", target_os = "android"))))]
+#[pymodule]
+mod _locale {
+    use rustpython_vm::{
+        builtins::{PyDictRef, PyIntRef, PyListRef, PyStrRef, PyTypeRef},
+        convert::ToPyException,
+        function::OptionalArg,
+        PyObjectRef, PyResult, VirtualMachine,
+    };
+    use std::{
+        ffi::{CStr, CString},
+        ptr,
+    };
+
+    #[pyattr]
+    use libc::{
+        ABDAY_1, ABDAY_2, ABDAY_3, ABDAY_4, ABDAY_5, ABDAY_6, ABDAY_7, ABMON_1, ABMON_10, ABMON_11,
+        ABMON_12, ABMON_2, ABMON_3, ABMON_4, ABMON_5, ABMON_6, ABMON_7, ABMON_8, ABMON_9,
+        ALT_DIGITS, AM_STR, CODESET, CRNCYSTR, DAY_1, DAY_2, DAY_3, DAY_4, DAY_5, DAY_6, DAY_7,
+        D_FMT, D_T_FMT, ERA, ERA_D_FMT, ERA_D_T_FMT, ERA_T_FMT, LC_ALL, LC_COLLATE, LC_CTYPE,
+        LC_MESSAGES, LC_MONETARY, LC_NUMERIC, LC_TIME, MON_1, MON_10, MON_11, MON_12, MON_2, MON_3,
+        MON_4, MON_5, MON_6, MON_7, MON_8, MON_9, NOEXPR, PM_STR, RADIXCHAR, THOUSEP, T_FMT,
+        T_FMT_AMPM, YESEXPR,
+    };
+
+    #[pyattr(name = "CHAR_MAX")]
+    fn char_max(vm: &VirtualMachine) -> PyIntRef {
+        vm.ctx.new_int(libc::c_char::MAX)
+    }
+
+    unsafe fn copy_grouping(group: *const libc::c_char, vm: &VirtualMachine) -> PyListRef {
+        let mut group_vec: Vec<PyObjectRef> = Vec::new();
+        if group.is_null() {
+            return vm.ctx.new_list(group_vec);
+        }
+
+        let mut ptr = group;
+        while ![0_i8, libc::c_char::MAX].contains(&*ptr) {
+            let val = vm.ctx.new_int(*ptr);
+            group_vec.push(val.into());
+            ptr = ptr.add(1);
+        }
+        // https://github.com/python/cpython/blob/677320348728ce058fa3579017e985af74a236d4/Modules/_localemodule.c#L80
+        if !group_vec.is_empty() {
+            group_vec.push(vm.ctx.new_int(0).into());
+        }
+        vm.ctx.new_list(group_vec)
+    }
+
+    unsafe fn pystr_from_raw_cstr(vm: &VirtualMachine, raw_ptr: *const libc::c_char) -> PyResult {
+        let slice = unsafe { CStr::from_ptr(raw_ptr) };
+        let string = slice
+            .to_str()
+            .expect("localeconv always return decodable string");
+        Ok(vm.new_pyobj(string))
+    }
+
+    #[pyattr(name = "Error", once)]
+    fn error(vm: &VirtualMachine) -> PyTypeRef {
+        vm.ctx.new_exception_type(
+            "locale",
+            "Error",
+            Some(vec![vm.ctx.exceptions.exception_type.to_owned()]),
+        )
+    }
+
+    #[pyfunction]
+    fn localeconv(vm: &VirtualMachine) -> PyResult<PyDictRef> {
+        let result = vm.ctx.new_dict();
+
+        unsafe {
+            let lc = libc::localeconv();
+
+            macro_rules! set_string_field {
+                ($field:ident) => {{
+                    result.set_item(
+                        stringify!($field),
+                        pystr_from_raw_cstr(vm, (*lc).$field)?,
+                        vm,
+                    )?
+                }};
+            }
+
+            macro_rules! set_int_field {
+                ($field:ident) => {{
+                    result.set_item(stringify!($field), vm.new_pyobj((*lc).$field), vm)?
+                }};
+            }
+
+            macro_rules! set_group_field {
+                ($field:ident) => {{
+                    result.set_item(
+                        stringify!($field),
+                        copy_grouping((*lc).$field, vm).into(),
+                        vm,
+                    )?
+                }};
+            }
+
+            set_group_field!(mon_grouping);
+            set_group_field!(grouping);
+            set_int_field!(int_frac_digits);
+            set_int_field!(frac_digits);
+            set_int_field!(p_cs_precedes);
+            set_int_field!(p_sep_by_space);
+            set_int_field!(n_cs_precedes);
+            set_int_field!(p_sign_posn);
+            set_int_field!(n_sign_posn);
+            set_string_field!(decimal_point);
+            set_string_field!(thousands_sep);
+            set_string_field!(int_curr_symbol);
+            set_string_field!(currency_symbol);
+            set_string_field!(mon_decimal_point);
+            set_string_field!(mon_thousands_sep);
+            set_int_field!(n_sep_by_space);
+            set_string_field!(positive_sign);
+            set_string_field!(negative_sign);
+        }
+        Ok(result)
+    }
+
+    #[derive(FromArgs)]
+    struct LocaleArgs {
+        #[pyarg(any)]
+        category: i32,
+        #[pyarg(any, optional)]
+        locale: OptionalArg<Option<PyStrRef>>,
+    }
+
+    #[pyfunction]
+    fn setlocale(args: LocaleArgs, vm: &VirtualMachine) -> PyResult {
+        unsafe {
+            let result = match args.locale.flatten() {
+                None => libc::setlocale(args.category, ptr::null()),
+                Some(locale) => {
+                    let c_locale: CString =
+                        CString::new(locale.as_str()).map_err(|e| e.to_pyexception(vm))?;
+                    libc::setlocale(args.category, c_locale.as_ptr())
+                }
+            };
+            if result.is_null() {
+                let error = error(vm);
+                return Err(vm.new_exception_msg(error, String::from("unsupported locale setting")));
+            }
+            pystr_from_raw_cstr(vm, result)
+        }
+    }
+}