Add basic validators

src/appsettings/__init__.py

@@ -14,12 +14,15 @@
     NestedSetting, ObjectSetting, ObjectTypeChecker, PositiveFloatSetting,
     PositiveIntegerSetting, SetSetting, Setting, SetTypeChecker, StringSetting,
     StringTypeChecker, TupleSetting, TupleTypeChecker, TypeChecker)
+from .validators import (
+    DictValuesTypeValidator, TypeValidator, ValuesTypeValidator)
 
 __all__ = (
     'BooleanSetting',
     'BooleanTypeChecker',
     'DictSetting',
     'DictTypeChecker',
+    'DictValuesTypeValidator',
     'FloatSetting',
     'FloatTypeChecker',
     'IntegerSetting',
@@ -40,7 +43,9 @@
     'StringTypeChecker',
     'TupleSetting',
     'TupleTypeChecker',
-    'TypeChecker'
+    'TypeChecker',
+    'TypeValidator',
+    'ValuesTypeValidator',
 )
 
 

src/appsettings/validators.py

@@ -0,0 +1,52 @@
+"""Basic set of setting validators."""
+from django.core.exceptions import ValidationError
+
+
+class TypeValidator(object):
+    """Validator which checks type of the value."""
+
+    message = 'Value %(value)s is not of type %(type)s.'
+
+    def __init__(self, value_type, message=None):
+        self.value_type = value_type
+        if message:
+            self.message = message
+
+    def __call__(self, value):
+        if not isinstance(value, self.value_type):
+            params = {'value': value, 'type': self.value_type.__name__}
+            raise ValidationError(self.message, params=params)
+
+
+class ValuesTypeValidator(object):
+    """Validator which checks types of iterable values."""
+
+    message = 'Element %(value)s is not of type %(type)s.'
+
+    def __init__(self, value_type, message=None):
+        self.value_type = value_type
+        if message:
+            self.message = message
+
+    def __call__(self, value):
+        for element in value:
+            if not isinstance(element, self.value_type):
+                params = {'value': element, 'type': self.value_type.__name__}
+                raise ValidationError(self.message, params=params)
+
+
+class DictValuesTypeValidator(object):
+    """Validator which checks types of dict values."""
+
+    message = "Item %(key)s's value %(value)s is not of type %(type)s."
+
+    def __init__(self, value_type, message=None):
+        self.value_type = value_type
+        if message:
+            self.message = message
+
+    def __call__(self, value):
+        for key, element in value.items():
+            if not isinstance(element, self.value_type):
+                params = {'key': key, 'value': element, 'type': self.value_type.__name__}
+                raise ValidationError(self.message, params=params)

tests/test_validators.py

@@ -0,0 +1,43 @@
+"""Test settings validators."""
+from django.core.exceptions import ValidationError
+from django.test import SimpleTestCase
+
+from appsettings import (
+    DictValuesTypeValidator, TypeValidator, ValuesTypeValidator)
+
+
+class TypeValidatorTestCase(SimpleTestCase):
+    """Test TypeValidator."""
+
+    def test_valid(self):
+        TypeValidator(int)(42)
+        TypeValidator(float)(4.5)
+        TypeValidator(list)([])
+
+    def test_invalid(self):
+        with self.assertRaisesMessage(ValidationError, "Value None is not of type int."):
+            TypeValidator(int)(None)
+
+
+class ValuesTypeValidatorTestCase(SimpleTestCase):
+    """Test ValuesTypeValidator."""
+
+    def test_valid(self):
+        ValuesTypeValidator(int)([42, 14, 1676])
+        ValuesTypeValidator(int)({42, 14, 1676})
+        ValuesTypeValidator(int)((42, 14, 1676))
+
+    def test_invalid(self):
+        with self.assertRaisesMessage(ValidationError, "Element None is not of type int."):
+            ValuesTypeValidator(int)([42, None, 1676])
+
+
+class DictValuesTypeValidatorTestCase(SimpleTestCase):
+    """Test DictValuesTypeValidator."""
+
+    def test_valid(self):
+        DictValuesTypeValidator(int)({'a': 42, 'b': 1676})
+
+    def test_invalid(self):
+        with self.assertRaisesMessage(ValidationError, "Item b's value None is not of type int."):
+            DictValuesTypeValidator(int)({'a': 42, 'b': None})