Merged the newforms-admin branch into trunk.

This is a backward incompatible change. The admin contrib app has been
refactored. The newforms module has several improvements including FormSets
and Media definitions.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@7967 bcc190cf-cafb-0310-a4f2-bffc1f526a37

5 files changed, 1101 insertions, 0 deletions

diff --git a/tests/regressiontests/forms/forms.py b/tests/regressiontests/forms/forms.py
index 041fa4054c..9add15163a 100644
--- a/tests/regressiontests/forms/forms.py
+++ b/tests/regressiontests/forms/forms.py
@@ -1667,4 +1667,76 @@ the list of errors is empty). You can also use it in {% if %} statements.
 <p><label>Password (again): <input type="password" name="password2" value="bar" /></label></p>
 <input type="submit" />
 </form>
+
+
+# The empty_permitted attribute ##############################################
+
+Sometimes (pretty much in formsets) we want to allow a form to pass validation
+if it is completely empty. We can accomplish this by using the empty_permitted
+agrument to a form constructor.
+
+>>> class SongForm(Form):
+...     artist = CharField()
+...     name = CharField()
+
+First let's show what happens id empty_permitted=False (the default):
+
+>>> data = {'artist': '', 'song': ''}
+
+>>> form = SongForm(data, empty_permitted=False)
+>>> form.is_valid()
+False
+>>> form.errors
+{'name': [u'This field is required.'], 'artist': [u'This field is required.']}
+>>> form.cleaned_data
+Traceback (most recent call last):
+...
+AttributeError: 'SongForm' object has no attribute 'cleaned_data'
+
+
+Now let's show what happens when empty_permitted=True and the form is empty.
+
+>>> form = SongForm(data, empty_permitted=True)
+>>> form.is_valid()
+True
+>>> form.errors
+{}
+>>> form.cleaned_data
+{}
+
+But if we fill in data for one of the fields, the form is no longer empty and
+the whole thing must pass validation.
+
+>>> data = {'artist': 'The Doors', 'song': ''}
+>>> form = SongForm(data, empty_permitted=False)
+>>> form.is_valid()
+False
+>>> form.errors
+{'name': [u'This field is required.']}
+>>> form.cleaned_data
+Traceback (most recent call last):
+...
+AttributeError: 'SongForm' object has no attribute 'cleaned_data'
+
+If a field is not given in the data then None is returned for its data. Lets
+make sure that when checking for empty_permitted that None is treated
+accordingly.
+
+>>> data = {'artist': None, 'song': ''}
+>>> form = SongForm(data, empty_permitted=True)
+>>> form.is_valid()
+True
+
+However, we *really* need to be sure we are checking for None as any data in
+initial that returns False on a boolean call needs to be treated literally.
+
+>>> class PriceForm(Form):
+...     amount = FloatField()
+...     qty = IntegerField()
+
+>>> data = {'amount': '0.0', 'qty': ''}
+>>> form = PriceForm(data, initial={'amount': 0.0}, empty_permitted=True)
+>>> form.is_valid()
+True
+
 """
diff --git a/tests/regressiontests/forms/formsets.py b/tests/regressiontests/forms/formsets.py
new file mode 100644
index 0000000000..dedc0a8e52
--- /dev/null
+++ b/tests/regressiontests/forms/formsets.py
@@ -0,0 +1,575 @@
+# -*- coding: utf-8 -*-
+tests = """
+# Basic FormSet creation and usage ############################################
+
+FormSet allows us to use multiple instance of the same form on 1 page. For now,
+the best way to create a FormSet is by using the formset_factory function.
+
+>>> from django.newforms import Form, CharField, IntegerField, ValidationError
+>>> from django.newforms.formsets import formset_factory, BaseFormSet
+
+>>> class Choice(Form):
+...     choice = CharField()
+...     votes = IntegerField()
+
+>>> ChoiceFormSet = formset_factory(Choice)
+
+A FormSet constructor takes the same arguments as Form. Let's create a FormSet
+for adding data. By default, it displays 1 blank form. It can display more,
+but we'll look at how to do so later.
+
+>>> formset = ChoiceFormSet(auto_id=False, prefix='choices')
+>>> print formset
+<input type="hidden" name="choices-TOTAL_FORMS" value="1" /><input type="hidden" name="choices-INITIAL_FORMS" value="0" /><input type="hidden" name="choices-MAX_FORMS" value="0" />
+<tr><th>Choice:</th><td><input type="text" name="choices-0-choice" /></td></tr>
+<tr><th>Votes:</th><td><input type="text" name="choices-0-votes" /></td></tr>
+
+
+On thing to note is that there needs to be a special value in the data. This
+value tells the FormSet how many forms were displayed so it can tell how
+many forms it needs to clean and validate. You could use javascript to create
+new forms on the client side, but they won't get validated unless you increment
+the TOTAL_FORMS field appropriately.
+
+>>> data = {
+...     'choices-TOTAL_FORMS': '1', # the number of forms rendered
+...     'choices-INITIAL_FORMS': '0', # the number of forms with initial data
+...     'choices-MAX_FORMS': '0', # the max number of forms
+...     'choices-0-choice': 'Calexico',
+...     'choices-0-votes': '100',
+... }
+
+We treat FormSet pretty much like we would treat a normal Form. FormSet has an
+is_valid method, and a cleaned_data or errors attribute depending on whether all
+the forms passed validation. However, unlike a Form instance, cleaned_data and
+errors will be a list of dicts rather than just a single dict.
+
+>>> formset = ChoiceFormSet(data, auto_id=False, prefix='choices')
+>>> formset.is_valid()
+True
+>>> [form.cleaned_data for form in formset.forms]
+[{'votes': 100, 'choice': u'Calexico'}]
+
+If a FormSet was not passed any data, its is_valid method should return False.
+>>> formset = ChoiceFormSet()
+>>> formset.is_valid()
+False
+
+FormSet instances can also have an error attribute if validation failed for
+any of the forms.
+
+>>> data = {
+...     'choices-TOTAL_FORMS': '1', # the number of forms rendered
+...     'choices-INITIAL_FORMS': '0', # the number of forms with initial data
+...     'choices-MAX_FORMS': '0', # the max number of forms
+...     'choices-0-choice': 'Calexico',
+...     'choices-0-votes': '',
+... }
+
+>>> formset = ChoiceFormSet(data, auto_id=False, prefix='choices')
+>>> formset.is_valid()
+False
+>>> formset.errors
+[{'votes': [u'This field is required.']}]
+
+
+We can also prefill a FormSet with existing data by providing an ``initial``
+argument to the constructor. ``initial`` should be a list of dicts. By default,
+an extra blank form is included.
+
+>>> initial = [{'choice': u'Calexico', 'votes': 100}]
+>>> formset = ChoiceFormSet(initial=initial, auto_id=False, prefix='choices')
+>>> for form in formset.forms:
+...    print form.as_ul()
+<li>Choice: <input type="text" name="choices-0-choice" value="Calexico" /></li>
+<li>Votes: <input type="text" name="choices-0-votes" value="100" /></li>
+<li>Choice: <input type="text" name="choices-1-choice" /></li>
+<li>Votes: <input type="text" name="choices-1-votes" /></li>
+
+
+Let's simulate what would happen if we submitted this form.
+
+>>> data = {
+...     'choices-TOTAL_FORMS': '2', # the number of forms rendered
+...     'choices-INITIAL_FORMS': '1', # the number of forms with initial data
+...     'choices-MAX_FORMS': '0', # the max number of forms
+...     'choices-0-choice': 'Calexico',
+...     'choices-0-votes': '100',
+...     'choices-1-choice': '',
+...     'choices-1-votes': '',
+... }
+
+>>> formset = ChoiceFormSet(data, auto_id=False, prefix='choices')
+>>> formset.is_valid()
+True
+>>> [form.cleaned_data for form in formset.forms]
+[{'votes': 100, 'choice': u'Calexico'}, {}]
+
+But the second form was blank! Shouldn't we get some errors? No. If we display
+a form as blank, it's ok for it to be submitted as blank. If we fill out even
+one of the fields of a blank form though, it will be validated. We may want to
+required that at least x number of forms are completed, but we'll show how to
+handle that later.
+
+>>> data = {
+...     'choices-TOTAL_FORMS': '2', # the number of forms rendered
+...     'choices-INITIAL_FORMS': '1', # the number of forms with initial data
+...     'choices-MAX_FORMS': '0', # the max number of forms
+...     'choices-0-choice': 'Calexico',
+...     'choices-0-votes': '100',
+...     'choices-1-choice': 'The Decemberists',
+...     'choices-1-votes': '', # missing value
+... }
+
+>>> formset = ChoiceFormSet(data, auto_id=False, prefix='choices')
+>>> formset.is_valid()
+False
+>>> formset.errors
+[{}, {'votes': [u'This field is required.']}]
+
+If we delete data that was pre-filled, we should get an error. Simply removing
+data from form fields isn't the proper way to delete it. We'll see how to
+handle that case later.
+
+>>> data = {
+...     'choices-TOTAL_FORMS': '2', # the number of forms rendered
+...     'choices-INITIAL_FORMS': '1', # the number of forms with initial data
+...     'choices-MAX_FORMS': '0', # the max number of forms
+...     'choices-0-choice': '', # deleted value
+...     'choices-0-votes': '', # deleted value
+...     'choices-1-choice': '',
+...     'choices-1-votes': '',
+... }
+
+>>> formset = ChoiceFormSet(data, auto_id=False, prefix='choices')
+>>> formset.is_valid()
+False
+>>> formset.errors
+[{'votes': [u'This field is required.'], 'choice': [u'This field is required.']}, {}]
+
+
+# Displaying more than 1 blank form ###########################################
+
+We can also display more than 1 empty form at a time. To do so, pass a
+extra argument to formset_factory.
+
+>>> ChoiceFormSet = formset_factory(Choice, extra=3)
+
+>>> formset = ChoiceFormSet(auto_id=False, prefix='choices')
+>>> for form in formset.forms:
+...    print form.as_ul()
+<li>Choice: <input type="text" name="choices-0-choice" /></li>
+<li>Votes: <input type="text" name="choices-0-votes" /></li>
+<li>Choice: <input type="text" name="choices-1-choice" /></li>
+<li>Votes: <input type="text" name="choices-1-votes" /></li>
+<li>Choice: <input type="text" name="choices-2-choice" /></li>
+<li>Votes: <input type="text" name="choices-2-votes" /></li>
+
+Since we displayed every form as blank, we will also accept them back as blank.
+This may seem a little strange, but later we will show how to require a minimum
+number of forms to be completed.
+
+>>> data = {
+...     'choices-TOTAL_FORMS': '3', # the number of forms rendered
+...     'choices-INITIAL_FORMS': '0', # the number of forms with initial data
+...     'choices-MAX_FORMS': '0', # the max number of forms
+...     'choices-0-choice': '',
+...     'choices-0-votes': '',
+...     'choices-1-choice': '',
+...     'choices-1-votes': '',
+...     'choices-2-choice': '',
+...     'choices-2-votes': '',
+... }
+
+>>> formset = ChoiceFormSet(data, auto_id=False, prefix='choices')
+>>> formset.is_valid()
+True
+>>> [form.cleaned_data for form in formset.forms]
+[{}, {}, {}]
+
+
+We can just fill out one of the forms.
+
+>>> data = {
+...     'choices-TOTAL_FORMS': '3', # the number of forms rendered
+...     'choices-INITIAL_FORMS': '0', # the number of forms with initial data
+...     'choices-MAX_FORMS': '0', # the max number of forms
+...     'choices-0-choice': 'Calexico',
+...     'choices-0-votes': '100',
+...     'choices-1-choice': '',
+...     'choices-1-votes': '',
+...     'choices-2-choice': '',
+...     'choices-2-votes': '',
+... }
+
+>>> formset = ChoiceFormSet(data, auto_id=False, prefix='choices')
+>>> formset.is_valid()
+True
+>>> [form.cleaned_data for form in formset.forms]
+[{'votes': 100, 'choice': u'Calexico'}, {}, {}]
+
+
+And once again, if we try to partially complete a form, validation will fail.
+
+>>> data = {
+...     'choices-TOTAL_FORMS': '3', # the number of forms rendered
+...     'choices-INITIAL_FORMS': '0', # the number of forms with initial data
+...     'choices-MAX_FORMS': '0', # the max number of forms
+...     'choices-0-choice': 'Calexico',
+...     'choices-0-votes': '100',
+...     'choices-1-choice': 'The Decemberists',
+...     'choices-1-votes': '', # missing value
+...     'choices-2-choice': '',
+...     'choices-2-votes': '',
+... }
+
+>>> formset = ChoiceFormSet(data, auto_id=False, prefix='choices')
+>>> formset.is_valid()
+False
+>>> formset.errors
+[{}, {'votes': [u'This field is required.']}, {}]
+
+
+The extra argument also works when the formset is pre-filled with initial
+data.
+
+>>> initial = [{'choice': u'Calexico', 'votes': 100}]
+>>> formset = ChoiceFormSet(initial=initial, auto_id=False, prefix='choices')
+>>> for form in formset.forms:
+...    print form.as_ul()
+<li>Choice: <input type="text" name="choices-0-choice" value="Calexico" /></li>
+<li>Votes: <input type="text" name="choices-0-votes" value="100" /></li>
+<li>Choice: <input type="text" name="choices-1-choice" /></li>
+<li>Votes: <input type="text" name="choices-1-votes" /></li>
+<li>Choice: <input type="text" name="choices-2-choice" /></li>
+<li>Votes: <input type="text" name="choices-2-votes" /></li>
+<li>Choice: <input type="text" name="choices-3-choice" /></li>
+<li>Votes: <input type="text" name="choices-3-votes" /></li>
+
+
+# FormSets with deletion ######################################################
+
+We can easily add deletion ability to a FormSet with an agrument to
+formset_factory. This will add a boolean field to each form instance. When
+that boolean field is True, the form will be in formset.deleted_forms
+
+>>> ChoiceFormSet = formset_factory(Choice, can_delete=True)
+
+>>> initial = [{'choice': u'Calexico', 'votes': 100}, {'choice': u'Fergie', 'votes': 900}]
+>>> formset = ChoiceFormSet(initial=initial, auto_id=False, prefix='choices')
+>>> for form in formset.forms:
+...    print form.as_ul()
+<li>Choice: <input type="text" name="choices-0-choice" value="Calexico" /></li>
+<li>Votes: <input type="text" name="choices-0-votes" value="100" /></li>
+<li>Delete: <input type="checkbox" name="choices-0-DELETE" /></li>
+<li>Choice: <input type="text" name="choices-1-choice" value="Fergie" /></li>
+<li>Votes: <input type="text" name="choices-1-votes" value="900" /></li>
+<li>Delete: <input type="checkbox" name="choices-1-DELETE" /></li>
+<li>Choice: <input type="text" name="choices-2-choice" /></li>
+<li>Votes: <input type="text" name="choices-2-votes" /></li>
+<li>Delete: <input type="checkbox" name="choices-2-DELETE" /></li>
+
+To delete something, we just need to set that form's special delete field to
+'on'. Let's go ahead and delete Fergie.
+
+>>> data = {
+...     'choices-TOTAL_FORMS': '3', # the number of forms rendered
+...     'choices-INITIAL_FORMS': '2', # the number of forms with initial data
+...     'choices-MAX_FORMS': '0', # the max number of forms
+...     'choices-0-choice': 'Calexico',
+...     'choices-0-votes': '100',
+...     'choices-0-DELETE': '',
+...     'choices-1-choice': 'Fergie',
+...     'choices-1-votes': '900',
+...     'choices-1-DELETE': 'on',
+...     'choices-2-choice': '',
+...     'choices-2-votes': '',
+...     'choices-2-DELETE': '',
+... }
+
+>>> formset = ChoiceFormSet(data, auto_id=False, prefix='choices')
+>>> formset.is_valid()
+True
+>>> [form.cleaned_data for form in formset.forms]
+[{'votes': 100, 'DELETE': False, 'choice': u'Calexico'}, {'votes': 900, 'DELETE': True, 'choice': u'Fergie'}, {}]
+>>> [form.cleaned_data for form in formset.deleted_forms]
+[{'votes': 900, 'DELETE': True, 'choice': u'Fergie'}]
+
+
+# FormSets with ordering ######################################################
+
+We can also add ordering ability to a FormSet with an agrument to
+formset_factory. This will add a integer field to each form instance. When
+form validation succeeds, [form.cleaned_data for form in formset.forms] will have the data in the correct
+order specified by the ordering fields. If a number is duplicated in the set
+of ordering fields, for instance form 0 and form 3 are both marked as 1, then
+the form index used as a secondary ordering criteria. In order to put
+something at the front of the list, you'd need to set it's order to 0.
+
+>>> ChoiceFormSet = formset_factory(Choice, can_order=True)
+
+>>> initial = [{'choice': u'Calexico', 'votes': 100}, {'choice': u'Fergie', 'votes': 900}]
+>>> formset = ChoiceFormSet(initial=initial, auto_id=False, prefix='choices')
+>>> for form in formset.forms:
+...    print form.as_ul()
+<li>Choice: <input type="text" name="choices-0-choice" value="Calexico" /></li>
+<li>Votes: <input type="text" name="choices-0-votes" value="100" /></li>
+<li>Order: <input type="text" name="choices-0-ORDER" value="1" /></li>
+<li>Choice: <input type="text" name="choices-1-choice" value="Fergie" /></li>
+<li>Votes: <input type="text" name="choices-1-votes" value="900" /></li>
+<li>Order: <input type="text" name="choices-1-ORDER" value="2" /></li>
+<li>Choice: <input type="text" name="choices-2-choice" /></li>
+<li>Votes: <input type="text" name="choices-2-votes" /></li>
+<li>Order: <input type="text" name="choices-2-ORDER" /></li>
+
+>>> data = {
+...     'choices-TOTAL_FORMS': '3', # the number of forms rendered
+...     'choices-INITIAL_FORMS': '2', # the number of forms with initial data
+...     'choices-MAX_FORMS': '0', # the max number of forms
+...     'choices-0-choice': 'Calexico',
+...     'choices-0-votes': '100',
+...     'choices-0-ORDER': '1',
+...     'choices-1-choice': 'Fergie',
+...     'choices-1-votes': '900',
+...     'choices-1-ORDER': '2',
+...     'choices-2-choice': 'The Decemberists',
+...     'choices-2-votes': '500',
+...     'choices-2-ORDER': '0',
+... }
+
+>>> formset = ChoiceFormSet(data, auto_id=False, prefix='choices')
+>>> formset.is_valid()
+True
+>>> for form in formset.ordered_forms:
+...    print form.cleaned_data
+{'votes': 500, 'ORDER': 0, 'choice': u'The Decemberists'}
+{'votes': 100, 'ORDER': 1, 'choice': u'Calexico'}
+{'votes': 900, 'ORDER': 2, 'choice': u'Fergie'}
+
+Ordering fields are allowed to be left blank, and if they *are* left blank,
+they will be sorted below everything else.
+
+>>> data = {
+...     'choices-TOTAL_FORMS': '4', # the number of forms rendered
+...     'choices-INITIAL_FORMS': '3', # the number of forms with initial data
+...     'choices-MAX_FORMS': '0', # the max number of forms
+...     'choices-0-choice': 'Calexico',
+...     'choices-0-votes': '100',
+...     'choices-0-ORDER': '1',
+...     'choices-1-choice': 'Fergie',
+...     'choices-1-votes': '900',
+...     'choices-1-ORDER': '2',
+...     'choices-2-choice': 'The Decemberists',
+...     'choices-2-votes': '500',
+...     'choices-2-ORDER': '',
+...     'choices-3-choice': 'Basia Bulat',
+...     'choices-3-votes': '50',
+...     'choices-3-ORDER': '',
+... }
+
+>>> formset = ChoiceFormSet(data, auto_id=False, prefix='choices')
+>>> formset.is_valid()
+True
+>>> for form in formset.ordered_forms:
+...    print form.cleaned_data
+{'votes': 100, 'ORDER': 1, 'choice': u'Calexico'}
+{'votes': 900, 'ORDER': 2, 'choice': u'Fergie'}
+{'votes': 500, 'ORDER': None, 'choice': u'The Decemberists'}
+{'votes': 50, 'ORDER': None, 'choice': u'Basia Bulat'}
+
+
+# FormSets with ordering + deletion ###########################################
+
+Let's try throwing ordering and deletion into the same form.
+
+>>> ChoiceFormSet = formset_factory(Choice, can_order=True, can_delete=True)
+
+>>> initial = [
+...     {'choice': u'Calexico', 'votes': 100},
+...     {'choice': u'Fergie', 'votes': 900},
+...     {'choice': u'The Decemberists', 'votes': 500},
+... ]
+>>> formset = ChoiceFormSet(initial=initial, auto_id=False, prefix='choices')
+>>> for form in formset.forms:
+...    print form.as_ul()
+<li>Choice: <input type="text" name="choices-0-choice" value="Calexico" /></li>
+<li>Votes: <input type="text" name="choices-0-votes" value="100" /></li>
+<li>Order: <input type="text" name="choices-0-ORDER" value="1" /></li>
+<li>Delete: <input type="checkbox" name="choices-0-DELETE" /></li>
+<li>Choice: <input type="text" name="choices-1-choice" value="Fergie" /></li>
+<li>Votes: <input type="text" name="choices-1-votes" value="900" /></li>
+<li>Order: <input type="text" name="choices-1-ORDER" value="2" /></li>
+<li>Delete: <input type="checkbox" name="choices-1-DELETE" /></li>
+<li>Choice: <input type="text" name="choices-2-choice" value="The Decemberists" /></li>
+<li>Votes: <input type="text" name="choices-2-votes" value="500" /></li>
+<li>Order: <input type="text" name="choices-2-ORDER" value="3" /></li>
+<li>Delete: <input type="checkbox" name="choices-2-DELETE" /></li>
+<li>Choice: <input type="text" name="choices-3-choice" /></li>
+<li>Votes: <input type="text" name="choices-3-votes" /></li>
+<li>Order: <input type="text" name="choices-3-ORDER" /></li>
+<li>Delete: <input type="checkbox" name="choices-3-DELETE" /></li>
+
+Let's delete Fergie, and put The Decemberists ahead of Calexico.
+
+>>> data = {
+...     'choices-TOTAL_FORMS': '4', # the number of forms rendered
+...     'choices-INITIAL_FORMS': '3', # the number of forms with initial data
+...     'choices-MAX_FORMS': '0', # the max number of forms
+...     'choices-0-choice': 'Calexico',
+...     'choices-0-votes': '100',
+...     'choices-0-ORDER': '1',
+...     'choices-0-DELETE': '',
+...     'choices-1-choice': 'Fergie',
+...     'choices-1-votes': '900',
+...     'choices-1-ORDER': '2',
+...     'choices-1-DELETE': 'on',
+...     'choices-2-choice': 'The Decemberists',
+...     'choices-2-votes': '500',
+...     'choices-2-ORDER': '0',
+...     'choices-2-DELETE': '',
+...     'choices-3-choice': '',
+...     'choices-3-votes': '',
+...     'choices-3-ORDER': '',
+...     'choices-3-DELETE': '',
+... }
+
+>>> formset = ChoiceFormSet(data, auto_id=False, prefix='choices')
+>>> formset.is_valid()
+True
+>>> for form in formset.ordered_forms:
+...    print form.cleaned_data
+{'votes': 500, 'DELETE': False, 'ORDER': 0, 'choice': u'The Decemberists'}
+{'votes': 100, 'DELETE': False, 'ORDER': 1, 'choice': u'Calexico'}
+>>> [form.cleaned_data for form in formset.deleted_forms]
+[{'votes': 900, 'DELETE': True, 'ORDER': 2, 'choice': u'Fergie'}]
+
+
+# FormSet clean hook ##########################################################
+
+FormSets have a hook for doing extra validation that shouldn't be tied to any
+particular form. It follows the same pattern as the clean hook on Forms.
+
+Let's define a FormSet that takes a list of favorite drinks, but raises am
+error if there are any duplicates.
+
+>>> class FavoriteDrinkForm(Form):
+...     name = CharField()
+...
+
+>>> class BaseFavoriteDrinksFormSet(BaseFormSet):
+...     def clean(self):
+...         seen_drinks = []
+...         for drink in self.cleaned_data:
+...             if drink['name'] in seen_drinks:
+...                 raise ValidationError('You may only specify a drink once.')
+...             seen_drinks.append(drink['name'])
+...
+
+>>> FavoriteDrinksFormSet = formset_factory(FavoriteDrinkForm,
+...     formset=BaseFavoriteDrinksFormSet, extra=3)
+
+We start out with a some duplicate data.
+
+>>> data = {
+...     'drinks-TOTAL_FORMS': '2', # the number of forms rendered
+...     'drinks-INITIAL_FORMS': '0', # the number of forms with initial data
+...     'drinks-MAX_FORMS': '0', # the max number of forms
+...     'drinks-0-name': 'Gin and Tonic',
+...     'drinks-1-name': 'Gin and Tonic',
+... }
+
+>>> formset = FavoriteDrinksFormSet(data, prefix='drinks')
+>>> formset.is_valid()
+False
+
+Any errors raised by formset.clean() are available via the
+formset.non_form_errors() method.
+
+>>> for error in formset.non_form_errors():
+...     print error
+You may only specify a drink once.
+
+
+Make sure we didn't break the valid case.
+
+>>> data = {
+...     'drinks-TOTAL_FORMS': '2', # the number of forms rendered
+...     'drinks-INITIAL_FORMS': '0', # the number of forms with initial data
+...     'drinks-MAX_FORMS': '0', # the max number of forms
+...     'drinks-0-name': 'Gin and Tonic',
+...     'drinks-1-name': 'Bloody Mary',
+... }
+
+>>> formset = FavoriteDrinksFormSet(data, prefix='drinks')
+>>> formset.is_valid()
+True
+>>> for error in formset.non_form_errors():
+...     print error
+
+# Limiting the maximum number of forms ########################################
+
+# Base case for max_num.
+
+>>> LimitedFavoriteDrinkFormSet = formset_factory(FavoriteDrinkForm, extra=5, max_num=2)
+>>> formset = LimitedFavoriteDrinkFormSet()
+>>> for form in formset.forms:
+...     print form
+<tr><th><label for="id_form-0-name">Name:</label></th><td><input type="text" name="form-0-name" id="id_form-0-name" /></td></tr>
+<tr><th><label for="id_form-1-name">Name:</label></th><td><input type="text" name="form-1-name" id="id_form-1-name" /></td></tr>
+
+# Ensure the that max_num has no affect when extra is less than max_forms.
+
+>>> LimitedFavoriteDrinkFormSet = formset_factory(FavoriteDrinkForm, extra=1, max_num=2)
+>>> formset = LimitedFavoriteDrinkFormSet()
+>>> for form in formset.forms:
+...     print form
+<tr><th><label for="id_form-0-name">Name:</label></th><td><input type="text" name="form-0-name" id="id_form-0-name" /></td></tr>
+
+# max_num with initial data
+
+# More initial forms than max_num will result in only the first max_num of
+# them to be displayed with no extra forms.
+
+>>> initial = [
+...     {'name': 'Gin Tonic'},
+...     {'name': 'Bloody Mary'},
+...     {'name': 'Jack and Coke'},
+... ]
+>>> LimitedFavoriteDrinkFormSet = formset_factory(FavoriteDrinkForm, extra=1, max_num=2)
+>>> formset = LimitedFavoriteDrinkFormSet(initial=initial)
+>>> for form in formset.forms:
+...     print form
+<tr><th><label for="id_form-0-name">Name:</label></th><td><input type="text" name="form-0-name" value="Gin Tonic" id="id_form-0-name" /></td></tr>
+<tr><th><label for="id_form-1-name">Name:</label></th><td><input type="text" name="form-1-name" value="Bloody Mary" id="id_form-1-name" /></td></tr>
+
+# One form from initial and extra=3 with max_num=2 should result in the one
+# initial form and one extra.
+
+>>> initial = [
+...     {'name': 'Gin Tonic'},
+... ]
+>>> LimitedFavoriteDrinkFormSet = formset_factory(FavoriteDrinkForm, extra=3, max_num=2)
+>>> formset = LimitedFavoriteDrinkFormSet(initial=initial)
+>>> for form in formset.forms:
+...     print form
+<tr><th><label for="id_form-0-name">Name:</label></th><td><input type="text" name="form-0-name" value="Gin Tonic" id="id_form-0-name" /></td></tr>
+<tr><th><label for="id_form-1-name">Name:</label></th><td><input type="text" name="form-1-name" id="id_form-1-name" /></td></tr>
+
+
+# Regression test for #6926 ##################################################
+
+Make sure the management form has the correct prefix.
+
+>>> formset = FavoriteDrinksFormSet()
+>>> formset.management_form.prefix
+'form'
+
+>>> formset = FavoriteDrinksFormSet(data={})
+>>> formset.management_form.prefix
+'form'
+
+>>> formset = FavoriteDrinksFormSet(initial={})
+>>> formset.management_form.prefix
+'form'
+
+"""
diff --git a/tests/regressiontests/forms/media.py b/tests/regressiontests/forms/media.py
new file mode 100644
index 0000000000..3ea48876f5
--- /dev/null
+++ b/tests/regressiontests/forms/media.py
@@ -0,0 +1,359 @@
+# -*- coding: utf-8 -*-
+# Tests for the media handling on widgets and forms
+
+media_tests = r"""
+>>> from django.newforms import TextInput, Media, TextInput, CharField, Form, MultiWidget
+>>> from django.conf import settings
+>>> ORIGINAL_MEDIA_URL = settings.MEDIA_URL
+>>> settings.MEDIA_URL = 'http://media.example.com/media/'
+
+# Check construction of media objects
+>>> m = Media(css={'all': ('path/to/css1','/path/to/css2')}, js=('/path/to/js1','http://media.other.com/path/to/js2','https://secure.other.com/path/to/js3'))
+>>> print m
+<link href="http://media.example.com/media/path/to/css1" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css2" type="text/css" media="all" rel="stylesheet" />
+<script type="text/javascript" src="/path/to/js1"></script>
+<script type="text/javascript" src="http://media.other.com/path/to/js2"></script>
+<script type="text/javascript" src="https://secure.other.com/path/to/js3"></script>
+
+>>> class Foo:
+...     css = {
+...        'all': ('path/to/css1','/path/to/css2')
+...     }
+...     js = ('/path/to/js1','http://media.other.com/path/to/js2','https://secure.other.com/path/to/js3')
+>>> m3 = Media(Foo)
+>>> print m3
+<link href="http://media.example.com/media/path/to/css1" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css2" type="text/css" media="all" rel="stylesheet" />
+<script type="text/javascript" src="/path/to/js1"></script>
+<script type="text/javascript" src="http://media.other.com/path/to/js2"></script>
+<script type="text/javascript" src="https://secure.other.com/path/to/js3"></script>
+
+>>> m3 = Media(Foo)
+>>> print m3
+<link href="http://media.example.com/media/path/to/css1" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css2" type="text/css" media="all" rel="stylesheet" />
+<script type="text/javascript" src="/path/to/js1"></script>
+<script type="text/javascript" src="http://media.other.com/path/to/js2"></script>
+<script type="text/javascript" src="https://secure.other.com/path/to/js3"></script>
+
+# A widget can exist without a media definition
+>>> class MyWidget(TextInput):
+...     pass
+
+>>> w = MyWidget()
+>>> print w.media
+<BLANKLINE>
+
+###############################################################
+# DSL Class-based media definitions
+###############################################################
+
+# A widget can define media if it needs to.
+# Any absolute path will be preserved; relative paths are combined
+# with the value of settings.MEDIA_URL
+>>> class MyWidget1(TextInput):
+...     class Media:
+...         css = {
+...            'all': ('path/to/css1','/path/to/css2')
+...         }
+...         js = ('/path/to/js1','http://media.other.com/path/to/js2','https://secure.other.com/path/to/js3')
+
+>>> w1 = MyWidget1()
+>>> print w1.media
+<link href="http://media.example.com/media/path/to/css1" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css2" type="text/css" media="all" rel="stylesheet" />
+<script type="text/javascript" src="/path/to/js1"></script>
+<script type="text/javascript" src="http://media.other.com/path/to/js2"></script>
+<script type="text/javascript" src="https://secure.other.com/path/to/js3"></script>
+
+# Media objects can be interrogated by media type
+>>> print w1.media['css']
+<link href="http://media.example.com/media/path/to/css1" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css2" type="text/css" media="all" rel="stylesheet" />
+
+>>> print w1.media['js']
+<script type="text/javascript" src="/path/to/js1"></script>
+<script type="text/javascript" src="http://media.other.com/path/to/js2"></script>
+<script type="text/javascript" src="https://secure.other.com/path/to/js3"></script>
+
+# Media objects can be combined. Any given media resource will appear only
+# once. Duplicated media definitions are ignored.
+>>> class MyWidget2(TextInput):
+...     class Media:
+...         css = {
+...            'all': ('/path/to/css2','/path/to/css3')
+...         }
+...         js = ('/path/to/js1','/path/to/js4')
+
+>>> class MyWidget3(TextInput):
+...     class Media:
+...         css = {
+...            'all': ('/path/to/css3','path/to/css1')
+...         }
+...         js = ('/path/to/js1','/path/to/js4')
+
+>>> w2 = MyWidget2()
+>>> w3 = MyWidget3()
+>>> print w1.media + w2.media + w3.media
+<link href="http://media.example.com/media/path/to/css1" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css2" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css3" type="text/css" media="all" rel="stylesheet" />
+<script type="text/javascript" src="/path/to/js1"></script>
+<script type="text/javascript" src="http://media.other.com/path/to/js2"></script>
+<script type="text/javascript" src="https://secure.other.com/path/to/js3"></script>
+<script type="text/javascript" src="/path/to/js4"></script>
+
+# Check that media addition hasn't affected the original objects
+>>> print w1.media
+<link href="http://media.example.com/media/path/to/css1" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css2" type="text/css" media="all" rel="stylesheet" />
+<script type="text/javascript" src="/path/to/js1"></script>
+<script type="text/javascript" src="http://media.other.com/path/to/js2"></script>
+<script type="text/javascript" src="https://secure.other.com/path/to/js3"></script>
+
+###############################################################
+# Property-based media definitions
+###############################################################
+
+# Widget media can be defined as a property
+>>> class MyWidget4(TextInput):
+...     def _media(self):
+...         return Media(css={'all': ('/some/path',)}, js = ('/some/js',))
+...     media = property(_media)
+
+>>> w4 = MyWidget4()
+>>> print w4.media
+<link href="/some/path" type="text/css" media="all" rel="stylesheet" />
+<script type="text/javascript" src="/some/js"></script>
+
+# Media properties can reference the media of their parents
+>>> class MyWidget5(MyWidget4):
+...     def _media(self):
+...         return super(MyWidget5, self).media + Media(css={'all': ('/other/path',)}, js = ('/other/js',))
+...     media = property(_media)
+
+>>> w5 = MyWidget5()
+>>> print w5.media
+<link href="/some/path" type="text/css" media="all" rel="stylesheet" />
+<link href="/other/path" type="text/css" media="all" rel="stylesheet" />
+<script type="text/javascript" src="/some/js"></script>
+<script type="text/javascript" src="/other/js"></script>
+
+# Media properties can reference the media of their parents,
+# even if the parent media was defined using a class
+>>> class MyWidget6(MyWidget1):
+...     def _media(self):
+...         return super(MyWidget6, self).media + Media(css={'all': ('/other/path',)}, js = ('/other/js',))
+...     media = property(_media)
+
+>>> w6 = MyWidget6()
+>>> print w6.media
+<link href="http://media.example.com/media/path/to/css1" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css2" type="text/css" media="all" rel="stylesheet" />
+<link href="/other/path" type="text/css" media="all" rel="stylesheet" />
+<script type="text/javascript" src="/path/to/js1"></script>
+<script type="text/javascript" src="http://media.other.com/path/to/js2"></script>
+<script type="text/javascript" src="https://secure.other.com/path/to/js3"></script>
+<script type="text/javascript" src="/other/js"></script>
+
+###############################################################
+# Inheritance of media
+###############################################################
+
+# If a widget extends another but provides no media definition, it inherits the parent widget's media
+>>> class MyWidget7(MyWidget1):
+...     pass
+
+>>> w7 = MyWidget7()
+>>> print w7.media
+<link href="http://media.example.com/media/path/to/css1" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css2" type="text/css" media="all" rel="stylesheet" />
+<script type="text/javascript" src="/path/to/js1"></script>
+<script type="text/javascript" src="http://media.other.com/path/to/js2"></script>
+<script type="text/javascript" src="https://secure.other.com/path/to/js3"></script>
+
+# If a widget extends another but defines media, it extends the parent widget's media by default
+>>> class MyWidget8(MyWidget1):
+...     class Media:
+...         css = {
+...            'all': ('/path/to/css3','path/to/css1')
+...         }
+...         js = ('/path/to/js1','/path/to/js4')
+
+>>> w8 = MyWidget8()
+>>> print w8.media
+<link href="http://media.example.com/media/path/to/css1" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css2" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css3" type="text/css" media="all" rel="stylesheet" />
+<script type="text/javascript" src="/path/to/js1"></script>
+<script type="text/javascript" src="http://media.other.com/path/to/js2"></script>
+<script type="text/javascript" src="https://secure.other.com/path/to/js3"></script>
+<script type="text/javascript" src="/path/to/js4"></script>
+
+# If a widget extends another but defines media, it extends the parents widget's media,
+# even if the parent defined media using a property.
+>>> class MyWidget9(MyWidget4):
+...     class Media:
+...         css = {
+...             'all': ('/other/path',)
+...         }
+...         js = ('/other/js',)
+
+>>> w9 = MyWidget9()
+>>> print w9.media
+<link href="/some/path" type="text/css" media="all" rel="stylesheet" />
+<link href="/other/path" type="text/css" media="all" rel="stylesheet" />
+<script type="text/javascript" src="/some/js"></script>
+<script type="text/javascript" src="/other/js"></script>
+
+# A widget can disable media inheritance by specifying 'extend=False'
+>>> class MyWidget10(MyWidget1):
+...     class Media:
+...         extend = False
+...         css = {
+...            'all': ('/path/to/css3','path/to/css1')
+...         }
+...         js = ('/path/to/js1','/path/to/js4')
+
+>>> w10 = MyWidget10()
+>>> print w10.media
+<link href="/path/to/css3" type="text/css" media="all" rel="stylesheet" />
+<link href="http://media.example.com/media/path/to/css1" type="text/css" media="all" rel="stylesheet" />
+<script type="text/javascript" src="/path/to/js1"></script>
+<script type="text/javascript" src="/path/to/js4"></script>
+
+# A widget can explicitly enable full media inheritance by specifying 'extend=True'
+>>> class MyWidget11(MyWidget1):
+...     class Media:
+...         extend = True
+...         css = {
+...            'all': ('/path/to/css3','path/to/css1')
+...         }
+...         js = ('/path/to/js1','/path/to/js4')
+
+>>> w11 = MyWidget11()
+>>> print w11.media
+<link href="http://media.example.com/media/path/to/css1" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css2" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css3" type="text/css" media="all" rel="stylesheet" />
+<script type="text/javascript" src="/path/to/js1"></script>
+<script type="text/javascript" src="http://media.other.com/path/to/js2"></script>
+<script type="text/javascript" src="https://secure.other.com/path/to/js3"></script>
+<script type="text/javascript" src="/path/to/js4"></script>
+
+# A widget can enable inheritance of one media type by specifying extend as a tuple
+>>> class MyWidget12(MyWidget1):
+...     class Media:
+...         extend = ('css',)
+...         css = {
+...            'all': ('/path/to/css3','path/to/css1')
+...         }
+...         js = ('/path/to/js1','/path/to/js4')
+
+>>> w12 = MyWidget12()
+>>> print w12.media
+<link href="http://media.example.com/media/path/to/css1" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css2" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css3" type="text/css" media="all" rel="stylesheet" />
+<script type="text/javascript" src="/path/to/js1"></script>
+<script type="text/javascript" src="/path/to/js4"></script>
+
+###############################################################
+# Multi-media handling for CSS
+###############################################################
+
+# A widget can define CSS media for multiple output media types
+>>> class MultimediaWidget(TextInput):
+...     class Media:
+...         css = {
+...            'screen, print': ('/file1','/file2'),
+...            'screen': ('/file3',),
+...            'print': ('/file4',)
+...         }
+...         js = ('/path/to/js1','/path/to/js4')
+
+>>> multimedia = MultimediaWidget()
+>>> print multimedia.media
+<link href="/file4" type="text/css" media="print" rel="stylesheet" />
+<link href="/file3" type="text/css" media="screen" rel="stylesheet" />
+<link href="/file1" type="text/css" media="screen, print" rel="stylesheet" />
+<link href="/file2" type="text/css" media="screen, print" rel="stylesheet" />
+<script type="text/javascript" src="/path/to/js1"></script>
+<script type="text/javascript" src="/path/to/js4"></script>
+
+###############################################################
+# Multiwidget media handling
+###############################################################
+
+# MultiWidgets have a default media definition that gets all the 
+# media from the component widgets
+>>> class MyMultiWidget(MultiWidget):
+...     def __init__(self, attrs=None):
+...         widgets = [MyWidget1, MyWidget2, MyWidget3]
+...         super(MyMultiWidget, self).__init__(widgets, attrs)
+            
+>>> mymulti = MyMultiWidget()
+>>> print mymulti.media   
+<link href="http://media.example.com/media/path/to/css1" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css2" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css3" type="text/css" media="all" rel="stylesheet" />
+<script type="text/javascript" src="/path/to/js1"></script>
+<script type="text/javascript" src="http://media.other.com/path/to/js2"></script>
+<script type="text/javascript" src="https://secure.other.com/path/to/js3"></script>
+<script type="text/javascript" src="/path/to/js4"></script>
+
+###############################################################
+# Media processing for forms
+###############################################################
+
+# You can ask a form for the media required by its widgets.
+>>> class MyForm(Form):
+...     field1 = CharField(max_length=20, widget=MyWidget1())
+...     field2 = CharField(max_length=20, widget=MyWidget2())
+>>> f1 = MyForm()
+>>> print f1.media
+<link href="http://media.example.com/media/path/to/css1" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css2" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css3" type="text/css" media="all" rel="stylesheet" />
+<script type="text/javascript" src="/path/to/js1"></script>
+<script type="text/javascript" src="http://media.other.com/path/to/js2"></script>
+<script type="text/javascript" src="https://secure.other.com/path/to/js3"></script>
+<script type="text/javascript" src="/path/to/js4"></script>
+
+# Form media can be combined to produce a single media definition.
+>>> class AnotherForm(Form):
+...     field3 = CharField(max_length=20, widget=MyWidget3())
+>>> f2 = AnotherForm()
+>>> print f1.media + f2.media
+<link href="http://media.example.com/media/path/to/css1" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css2" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css3" type="text/css" media="all" rel="stylesheet" />
+<script type="text/javascript" src="/path/to/js1"></script>
+<script type="text/javascript" src="http://media.other.com/path/to/js2"></script>
+<script type="text/javascript" src="https://secure.other.com/path/to/js3"></script>
+<script type="text/javascript" src="/path/to/js4"></script>
+
+# Forms can also define media, following the same rules as widgets.
+>>> class FormWithMedia(Form):
+...     field1 = CharField(max_length=20, widget=MyWidget1())
+...     field2 = CharField(max_length=20, widget=MyWidget2())
+...     class Media:
+...         js = ('/some/form/javascript',)
+...         css = {
+...             'all': ('/some/form/css',)
+...         }
+>>> f3 = FormWithMedia()
+>>> print f3.media
+<link href="http://media.example.com/media/path/to/css1" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css2" type="text/css" media="all" rel="stylesheet" />
+<link href="/path/to/css3" type="text/css" media="all" rel="stylesheet" />
+<link href="/some/form/css" type="text/css" media="all" rel="stylesheet" />
+<script type="text/javascript" src="/path/to/js1"></script>
+<script type="text/javascript" src="http://media.other.com/path/to/js2"></script>
+<script type="text/javascript" src="https://secure.other.com/path/to/js3"></script>
+<script type="text/javascript" src="/path/to/js4"></script>
+<script type="text/javascript" src="/some/form/javascript"></script>
+
+>>> settings.MEDIA_URL = ORIGINAL_MEDIA_URL
+"""
\ No newline at end of file
diff --git a/tests/regressiontests/forms/tests.py b/tests/regressiontests/forms/tests.py
index bb0e30b874..ff8213c8d9 100644
--- a/tests/regressiontests/forms/tests.py
+++ b/tests/regressiontests/forms/tests.py
@@ -26,6 +26,8 @@ from localflavor.za import tests as localflavor_za_tests
 from regressions import tests as regression_tests
 from util import tests as util_tests
 from widgets import tests as widgets_tests
+from formsets import tests as formset_tests
+from media import media_tests
 
 __test__ = {
     'extra_tests': extra_tests,
@@ -53,6 +55,8 @@ __test__ = {
     'localflavor_us_tests': localflavor_us_tests,
     'localflavor_za_tests': localflavor_za_tests,
     'regression_tests': regression_tests,
+    'formset_tests': formset_tests,
+    'media_tests': media_tests,
     'util_tests': util_tests,
     'widgets_tests': widgets_tests,
 }
diff --git a/tests/regressiontests/forms/widgets.py b/tests/regressiontests/forms/widgets.py
index 2c6b51a8ec..e0837ab5b3 100644
--- a/tests/regressiontests/forms/widgets.py
+++ b/tests/regressiontests/forms/widgets.py
@@ -202,6 +202,30 @@ u'<input type="file" class="fun" name="email" />'
 >>> w.render('email', 'ŠĐĆŽćžšđ', attrs={'class': 'fun'})
 u'<input type="file" class="fun" name="email" />'
 
+Test for the behavior of _has_changed for FileInput. The value of data will
+more than likely come from request.FILES. The value of initial data will
+likely be a filename stored in the database. Since its value is of no use to
+a FileInput it is ignored.
+
+>>> w = FileInput()
+
+# No file was uploaded and no initial data.
+>>> w._has_changed(u'', None)
+False
+
+# A file was uploaded and no initial data.
+>>> w._has_changed(u'', {'filename': 'resume.txt', 'content': 'My resume'})
+True
+
+# A file was not uploaded, but there is initial data
+>>> w._has_changed(u'resume.txt', None)
+False
+
+# A file was uploaded and there is initial data (file identity is not dealt
+# with here)
+>>> w._has_changed('resume.txt', {'filename': 'resume.txt', 'content': 'My resume'})
+True
+
 # Textarea Widget #############################################################
 
 >>> w = Textarea()
@@ -292,6 +316,21 @@ checkboxes).
 >>> w.value_from_datadict({}, {}, 'testing')
 False
 
+>>> w._has_changed(None, None)
+False
+>>> w._has_changed(None, u'')
+False
+>>> w._has_changed(u'', None)
+False
+>>> w._has_changed(u'', u'')
+False
+>>> w._has_changed(False, u'on')
+True
+>>> w._has_changed(True, u'on')
+False
+>>> w._has_changed(True, u'')
+True
+
 # Select Widget ###############################################################
 
 >>> w = Select()
@@ -573,6 +612,20 @@ If 'choices' is passed to both the constructor and render(), then they'll both b
 >>> w.render('nums', ['ŠĐĆŽćžšđ'], choices=[('ŠĐĆŽćžšđ', 'ŠĐabcĆŽćžšđ'), ('ćžšđ', 'abcćžšđ')])
 u'<select multiple="multiple" name="nums">\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="\u0160\u0110\u0106\u017d\u0107\u017e\u0161\u0111" selected="selected">\u0160\u0110abc\u0106\u017d\u0107\u017e\u0161\u0111</option>\n<option value="\u0107\u017e\u0161\u0111">abc\u0107\u017e\u0161\u0111</option>\n</select>'
 
+# Test the usage of _has_changed
+>>> w._has_changed(None, None)
+False
+>>> w._has_changed([], None)
+False
+>>> w._has_changed(None, [u'1'])
+True
+>>> w._has_changed([1, 2], [u'1', u'2'])
+False
+>>> w._has_changed([1, 2], [u'1'])
+True
+>>> w._has_changed([1, 2], [u'1', u'3'])
+True
+
 # RadioSelect Widget ##########################################################
 
 >>> w = RadioSelect()
@@ -871,6 +924,20 @@ If 'choices' is passed to both the constructor and render(), then they'll both b
 <li><label><input type="checkbox" name="escape" value="good" /> you &gt; me</label></li>
 </ul>
 
+# Test the usage of _has_changed
+>>> w._has_changed(None, None)
+False
+>>> w._has_changed([], None)
+False
+>>> w._has_changed(None, [u'1'])
+True
+>>> w._has_changed([1, 2], [u'1', u'2'])
+False
+>>> w._has_changed([1, 2], [u'1'])
+True
+>>> w._has_changed([1, 2], [u'1', u'3'])
+True
+
 # Unicode choices are correctly rendered as HTML
 >>> w.render('nums', ['ŠĐĆŽćžšđ'], choices=[('ŠĐĆŽćžšđ', 'ŠĐabcĆŽćžšđ'), ('ćžšđ', 'abcćžšđ')])
 u'<ul>\n<li><label><input type="checkbox" name="nums" value="1" /> 1</label></li>\n<li><label><input type="checkbox" name="nums" value="2" /> 2</label></li>\n<li><label><input type="checkbox" name="nums" value="3" /> 3</label></li>\n<li><label><input checked="checked" type="checkbox" name="nums" value="\u0160\u0110\u0106\u017d\u0107\u017e\u0161\u0111" /> \u0160\u0110abc\u0106\u017d\u0107\u017e\u0161\u0111</label></li>\n<li><label><input type="checkbox" name="nums" value="\u0107\u017e\u0161\u0111" /> abc\u0107\u017e\u0161\u0111</label></li>\n</ul>'
@@ -895,6 +962,25 @@ u'<input id="foo_0" type="text" class="big" value="john" name="name_0" /><br /><
 >>> w.render('name', ['john', 'lennon'])
 u'<input id="bar_0" type="text" class="big" value="john" name="name_0" /><br /><input id="bar_1" type="text" class="small" value="lennon" name="name_1" />'
 
+>>> w = MyMultiWidget(widgets=(TextInput(), TextInput()))
+
+# test with no initial data
+>>> w._has_changed(None, [u'john', u'lennon'])
+True
+
+# test when the data is the same as initial
+>>> w._has_changed(u'john__lennon', [u'john', u'lennon'])
+False
+
+# test when the first widget's data has changed
+>>> w._has_changed(u'john__lennon', [u'alfred', u'lennon'])
+True
+
+# test when the last widget's data has changed. this ensures that it is not
+# short circuiting while testing the widgets.
+>>> w._has_changed(u'john__lennon', [u'john', u'denver'])
+True
+
 # SplitDateTimeWidget #########################################################
 
 >>> w = SplitDateTimeWidget()
@@ -913,6 +999,11 @@ included on both widgets.
 >>> w.render('date', datetime.datetime(2006, 1, 10, 7, 30))
 u'<input type="text" class="pretty" value="2006-01-10" name="date_0" /><input type="text" class="pretty" value="07:30:00" name="date_1" />'
 
+>>> w._has_changed(datetime.datetime(2008, 5, 5, 12, 40, 00), [u'2008-05-05', u'12:40:00'])
+False
+>>> w._has_changed(datetime.datetime(2008, 5, 5, 12, 40, 00), [u'2008-05-05', u'12:41:00'])
+True
+
 # DateTimeInput ###############################################################
 
 >>> w = DateTimeInput()