🐛 Fix max_length for unicode strings (#758)

Co-authored-by: Samuel Colvin <[email protected]>

Author: lig

src/validators/string.rs

@@ -93,17 +93,23 @@ impl Validator for StrConstrainedValidator {
         if self.strip_whitespace {
             str = str.trim();
         }
+
+        let str_len: Option<usize> = if self.min_length.is_some() | self.max_length.is_some() {
+            Some(str.chars().count())
+        } else {
+            None
+        };
         if let Some(min_length) = self.min_length {
-            if str.len() < min_length {
-                // return py_schema_err!("{} is shorter than {}", str, min_length);
+            if str_len.unwrap() < min_length {
                 return Err(ValError::new(ErrorType::StringTooShort { min_length }, input));
             }
         }
         if let Some(max_length) = self.max_length {
-            if str.len() > max_length {
+            if str_len.unwrap() > max_length {
                 return Err(ValError::new(ErrorType::StringTooLong { max_length }, input));
             }
         }
+
         if let Some(pattern) = &self.pattern {
             if !pattern.is_match(str) {
                 return Err(ValError::new(

tests/validators/test_string.py

@@ -1,6 +1,6 @@
 import re
 from decimal import Decimal
-from typing import Any, Dict
+from typing import Any, Dict, Union
 
 import pytest
 
@@ -134,12 +134,28 @@ def test_unicode_error():
     ]
 
 
-def test_str_constrained():
-    v = SchemaValidator({'type': 'str', 'max_length': 5})
-    assert v.validate_python('test') == 'test'
-
-    with pytest.raises(ValidationError, match='String should have at most 5 characters'):
-        v.validate_python('test long')
+@pytest.mark.parametrize(
+    ('data', 'max_length', 'error'),
+    [
+        pytest.param('test', 5, None, id='short string'),
+        pytest.param('test long', 5, 'String should have at most 5 characters', id='long string'),
+        pytest.param('␛⯋℃▤', 5, None, id='short string with unicode characters'),
+        pytest.param(
+            '␛⯋℃▤⩥⠫⳼⣪⨺✒⧐♳⩚⏭⏣⍥┙⧃Ⰴ┽⏏♜',
+            5,
+            'String should have at most 5 characters',
+            id='long string with unicode characters',
+        ),
+        pytest.param('а' * 25, 32, None, id='a lot of `а`s'),
+    ],
+)
+def test_str_constrained(data: str, max_length: int, error: Union[re.Pattern, None]):
+    v = SchemaValidator({'type': 'str', 'max_length': max_length})
+    if error is None:
+        assert v.validate_python(data) == data
+    else:
+        with pytest.raises(ValidationError, match=error):
+            v.validate_python(data)
 
 
 def test_str_constrained_config():