Merge branch 'master' of https://github.com/adamreeve/mongoengine into 459

mongoengine/base.py

@@ -25,7 +25,15 @@ class InvalidDocumentError(Exception):
 
 class ValidationError(AssertionError):
     """Validation exception.
+
+    May represent an error validating a field or a
+    document containing fields with validation errors.
+
+    :ivar errors: A dictionary of errors for fields within this
+        document or list, or None if the error is for an
+        individual field.
     """
+
     errors = {}
     field_name = None
     _message = None
@@ -43,10 +51,12 @@ class ValidationError(AssertionError):
 
     def __getattribute__(self, name):
         message = super(ValidationError, self).__getattribute__(name)
-        if name == 'message' and self.field_name:
-            return message + ' ("%s")' % self.field_name
-        else:
-            return message
+        if name == 'message':
+            if self.field_name:
+                message += ' ("%s")' % self.field_name
+            if self.errors:
+                message += ':\n' + self._format_errors()
+        return message
 
     def _get_message(self):
         return self._message
@@ -57,6 +67,13 @@ class ValidationError(AssertionError):
     message = property(_get_message, _set_message)
 
     def to_dict(self):
+        """Returns a dictionary of all errors within a document
+
+        Keys are field names or list indices and values are the
+        validation error messages, or a nested dictionary of
+        errors for an embedded document or list.
+        """
+
         def build_dict(source):
             errors_dict = {}
             if not source:
@@ -73,6 +90,20 @@ class ValidationError(AssertionError):
             return {}
         return build_dict(self.errors)
 
+    def _format_errors(self):
+        """Returns a string listing all errors within a document"""
+
+        def format_error(field, value, prefix=''):
+            if isinstance(value, dict):
+                new_prefix = (prefix + '.' if prefix else '') + str(field)
+                return '\n'.join(
+                        [format_error(k, value[k], new_prefix) for k in value])
+            else:
+                return (prefix + ": " if prefix else '') + str(value)
+
+        return '\n'.join(
+                [format_error(k, v) for k, v in self.to_dict().items()])
+
 
 _document_registry = {}