Document the ValidationError class

docs/apireference.rst

@@ -31,6 +31,9 @@ Documents
 .. autoclass:: mongoengine.document.MapReduceDocument
   :members:
 
+.. autoclass:: mongoengine.ValidationError
+  :members:
+
 Querying
 ========
 

docs/guide/defining-documents.rst

@@ -98,7 +98,7 @@ arguments can be set on all fields:
 
 :attr:`required` (Default: False)
     If set to True and the field is not set on the document instance, a
-    :class:`~mongoengine.base.ValidationError` will be raised when the document is
+    :class:`~mongoengine.ValidationError` will be raised when the document is
     validated.
 
 :attr:`default` (Default: None)

docs/guide/document-instances.rst

@@ -91,5 +91,5 @@ is an alias to :attr:`id`::
 .. note::
 
    If you define your own primary key field, the field implicitly becomes
-   required, so a :class:`ValidationError` will be thrown if you don't provide
-   it.
+   required, so a :class:`~mongoengine.ValidationError` will be thrown if
+   you don't provide it.

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
@@ -57,6 +65,13 @@ 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: