FieldFilter cleans iterable values correctly

Fixes #2

filternaut/filters.py

@@ -2,6 +2,10 @@
 
 from __future__ import absolute_import, unicode_literals
 
+from collections import Iterable
+
+import six
+
 from django.forms import (BooleanField, CharField, ChoiceField, ComboField,
                           DateField, DateTimeField, DecimalField, EmailField,
                           FilePathField, FloatField, ImageField, IntegerField,
@@ -25,6 +29,13 @@
     'TimeFilter', 'TypedChoiceFilter', 'URLFilter']
 
 
+def is_listlike(val):
+    """
+    True if `val` is an iterable (list, tuple, ...) but not a string
+    """
+    return isinstance(val, Iterable) and not isinstance(val, six.string_types)
+
+
 class FieldFilter(Filter):
     """
     FieldFilters use a django.forms.Field to clean their input value when
@@ -42,7 +53,10 @@ def __init__(self, dest, field, **kwargs):
         super(FieldFilter, self).__init__(dest, **kwargs)
 
     def clean(self, value):
-        return self.field.clean(value)
+        if is_listlike(value):
+            return type(value)(self.field.clean(v) for v in value)
+        else:
+            return self.field.clean(value)
 
 
 # -- mixtures of fieldfilter and django fields requiring additional arguments

tests/test_filters.py

@@ -9,7 +9,8 @@
 from django import VERSION as DJANGO_VERSION
 from django.utils.datastructures import MultiValueDict
 from filternaut import Filter, Optional
-from filternaut.filters import ChoiceFilter, FilePathFilter, RegexFilter
+from filternaut.filters import (CharFilter, ChoiceFilter, FilePathFilter,
+                                RegexFilter)
 from tests.util import NopeFilter, flatten_qobj
 
 
@@ -311,6 +312,20 @@ def test_instantiate_all_filterfields_without_special_args(self):
             else:
                 assert not hasattr(filternaut.filters, f)
 
+    def test_listlike_values_cleaned_individually(self):
+        f = CharFilter('fieldname', lookups='exact,in')
+        data = MultiValueDict({
+            'fieldname': ['single value'],  # MVDict treats 1-list as single
+            'fieldname__in': ['multiple', 'values'],
+        })
+        expected = {
+            'fieldname': 'single value',
+            'fieldname__in': ['multiple', 'values']
+        }
+        f.parse(data)
+        actual = dict(flatten_qobj(f.Q))
+        assert expected == actual
+
 
 class DefaultValueTests(TestCase):