diff --git a/Lib/test/test_str.py b/Lib/test/test_str.py
@@ -792,7 +792,6 @@ def test_isdecimal(self):
        for ch in ['\U0001D7F6', '\U00011066', '\U000104A0']:
            self.assertTrue(ch.isdecimal(), '{!a} is decimal.'.format(ch))

-    @unittest.expectedFailure  # TODO: RUSTPYTHON; AssertionError: False != True
    def test_isdigit(self):
        super().test_isdigit()
        self.checkequalnofix(True, '\u2460', 'isdigit')

diff --git a/crates/sre_engine/src/string.rs b/crates/sre_engine/src/string.rs
@@ -1,4 +1,4 @@
-use icu_properties::props::{CanonicalCombiningClass, EnumeratedProperty};
use rustpython_wtf8::Wtf8;

#[derive(Debug, Clone, Copy)]
@@ -444,9 +444,10 @@ pub(crate) const fn is_uni_linebreak(ch: u32) -> bool {
pub(crate) fn is_uni_alnum(ch: u32) -> bool {
    // TODO: check with cpython
    char::try_from(ch)
-        .map(|x| {
-            x.is_alphanumeric()
-                && CanonicalCombiningClass::for_char(x) == CanonicalCombiningClass::NotReordered
        })
        .unwrap_or(false)
}

diff --git a/crates/vm/src/builtins/str.rs b/crates/vm/src/builtins/str.rs
@@ -45,8 +45,8 @@ use rustpython_common::{
};

use icu_properties::props::{
-    BidiClass, BinaryProperty, CanonicalCombiningClass, EnumeratedProperty, GeneralCategory,
-    XidContinue, XidStart,
};
use unicode_casing::CharExt;

@@ -949,23 +949,30 @@ impl PyStr {
    fn isalnum(&self) -> bool {
        !self.data.is_empty()
            && self.char_all(|c| {
-                c.is_alphanumeric()
-                    && CanonicalCombiningClass::for_char(c) == CanonicalCombiningClass::NotReordered
            })
    }

    #[pymethod]
    fn isnumeric(&self) -> bool {
-        !self.data.is_empty() && self.char_all(char::is_numeric)
    }

    #[pymethod]
    fn isdigit(&self) -> bool {
-        // python's isdigit also checks if exponents are digits, these are the unicode codepoints for exponents
        !self.data.is_empty()
            && self.char_all(|c| {
-                c.is_ascii_digit()
-                    || matches!(c, '⁰' | '¹' | '²' | '³' | '⁴' | '⁵' | '⁶' | '⁷' | '⁸' | '⁹')
            })
    }

@@ -1064,7 +1071,9 @@ impl PyStr {

    #[pymethod]
    fn isalpha(&self) -> bool {
-        !self.data.is_empty() && self.char_all(char::is_alphabetic)
    }

    #[pymethod]

diff --git a/extra_tests/snippets/builtin_str.py b/extra_tests/snippets/builtin_str.py
@@ -72,16 +72,29 @@
assert "\u1c89".istitle()
# assert "Ǳ".title() == "ǲ"
assert a.isalpha()

# Combining characters differ slightly between Rust and Python
assert "\u006e".isalnum()
assert not "\u0303".isalnum()
assert not "\u006e\u0303".isalnum()
assert "\u00f1".isalnum()
assert not "\u0345".isalnum()
for raw in range(0x0363, 0x036F):
    assert not chr(raw).isalnum()

s = "1 2 3"
assert s.split(" ", 1) == ["1", "2 3"]
assert s.rsplit(" ", 1) == ["1 2", "3"]