Added ListField type with unit tests

mongomap/fields.py

@@ -5,7 +5,7 @@ import re
 import pymongo
 
 
-__all__ = ['StringField', 'IntField', 'EmbeddedDocumentField', 
+__all__ = ['StringField', 'IntField', 'EmbeddedDocumentField', 'ListField',
            'ObjectIdField', 'ValidationError']
 
 
@@ -17,8 +17,14 @@ class StringField(BaseField):
         self.regex = re.compile(regex) if regex else None
         self.max_length = max_length
         super(StringField, self).__init__(**kwargs)
+    
+    def _to_python(self, value):
+        assert(isinstance(value, (str, unicode)))
+        return unicode(value)
 
     def _validate(self, value):
+        assert(isinstance(value, (str, unicode)))
+
         if self.max_length is not None and len(value) > self.max_length:
             raise ValidationError('String value is too long')
 
@@ -36,9 +42,12 @@ class IntField(BaseField):
         super(IntField, self).__init__(**kwargs)
     
     def _to_python(self, value):
+        assert(isinstance(value, int))
         return int(value)
 
     def _validate(self, value):
+        assert(isinstance(value, int))
+
         if self.min_value is not None and value < self.min_value:
             raise ValidationError('Integer value is too small')
 
@@ -74,3 +83,41 @@ class EmbeddedDocumentField(BaseField):
         if not isinstance(value, self.document):
             raise ValidationError('Invalid embedded document instance '
                                   'provided to an EmbeddedDocumentField')
+
+
+class ListField(BaseField):
+    """A list field that wraps a standard field, allowing multiple instances
+    of the field to be used as a list in the database.
+    """
+
+    def __init__(self, field, **kwargs):
+        if not isinstance(field, BaseField):
+            raise ValidationError('Argument to ListField constructor must be '
+                                  'a valid field')
+        self.field = field
+        super(ListField, self).__init__(**kwargs)
+
+    def _to_python(self, value):
+        assert(isinstance(value, (list, tuple)))
+        return list(value)
+
+    def _to_mongo(self, value):
+        return [self.field._to_mongo(item) for item in value]
+
+    def _validate(self, value):
+        """Make sure that a list of valid fields is being used.
+        """
+#        print
+#        print value
+#        print type(value)
+#        print isinstance(value, list)
+#        print
+        if not isinstance(value, (list, tuple)):
+            raise ValidationError('Only lists and tuples may be used in a '
+                                  'list field')
+
+        try:
+            [self.field._validate(item) for item in value]
+        except:
+            raise ValidationError('All items in a list field must be of the '
+                                  'specified type')