id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
21523	Models DateField to_python method no longer supports mock dates.	hugo@…		"In between 1.4 and 1.5 a change was made to django.db.models.fields.DateField.to_python method that broke the use of mock dates in unit testing. This makes testing of models with mock dates impossible.

The to_python method in the DateField (and DateTimeField) is used to parse field input into the relevant python type. In the case of a DateField this involves checking for datetime.date and datetime.datetime types, and in the event of neither of these matching, it is assumed that the input is a string and an attempt is made to parse the value.

The parse_date function internally performs a regex match, and therefore implicitly expects a string argument. If the argument is not a string an error is raised.

This causes a problem when attempting to mock a date or datetime object for testing purposes. Using the method described (see http://bit.ly/1bYLdIC) tests will fail as the FakeDate mock fails all of the above (it is neither datetime nor date, and is not a string). I have submitted a question on StackOverflow (see http://bit.ly/187sUU9) which describes a concrete example.

In Django 1.4.x a mock Date / DateTime object could be used as prior to the parse_date check a call was made to ""django.utils.encoding.smart_str"", which converted the FakeDate to a parseable string.

Steps to reproduce:

Create a model with a DateField
Create a test that saves the model using datetime.date.today() as the field value (should pass) 
Create a second test that uses a FakeDate (see http://bit.ly/1bYLdIC)  to mock the datetime.date and provide a fake today() implementation

This second test should fail with ""TypeError: expected string or buffer"", as the FakeDate cannot be parsed.

Repeat this test with the 1.4.x branch - test should pass."	Cleanup/optimization	new	Database layer (models, ORM)	1.6	Normal			hugo@… Simon Charette	Accepted	1	0	0	1	0	0