247 / 478
expected_error
=
escape
(
"You've already got this in your list"
)
self
.
assertContains
(
response
,
expected_error
)
self
.
assertTemplateUsed
(
response
,
'list.html'
)
self
.
assertEqual
(
Item
.
objects
.
all
()
.
count
(),
1
)
Gives:
django.db.utils.IntegrityError: UNIQUE constraint failed: lists_item.list_id,
lists_item.text
We want to avoid integrity errors! Ideally, we want the call to
is_valid
to somehow
notice the duplication error before we even try to save, but to do that, our form will
need to know what list it’s being used for, in advance.
Let’s put a skip on that test for now:
lists/tests/test_views.py (ch12l015).
from
unittest
import
skip
[
...
]
@skip
def
test_duplicate_item_validation_errors_end_up_on_lists_page
(
self
):
A More Complex Form to Handle Uniqueness Validation
The form to create a new list only needs to know one thing, the new item text. A form
which validates that list items are unique needs to know both. Just like we overrode the
save method on our
ItemForm
, this time we’ll override the constructor on our new form
class so that it knows what list it applies to.
We duplicate our tests for the previous form, tweaking them slightly:
lists/tests/test_forms.py (ch12l016).
from
lists.forms
import
(
DUPLICATE_ITEM_ERROR
,
EMPTY_LIST_ERROR
,
ExistingListItemForm
,
ItemForm
)
[
...
]
class
ExistingListItemFormTest
(
TestCase
):
def
test_form_renders_item_text_input
(
self
):
list_
=
List
.
objects
.
create
()
form
=
ExistingListItemForm
(
for_list
=
list_
)
self
.
assertIn
(
'placeholder="Enter a to-do item"'
,
form
.
as_p
())
def
test_form_validation_for_blank_items
(
self
):
list_
=
List
.
objects
.
create
()
form
=
ExistingListItemForm
(
for_list
=
list_
,
data
=
{
'text'
:
''
})
self
.
assertFalse
(
form
.
is_valid
())
self
.
assertEqual
(
form
.
errors
[
'text'
], [
EMPTY_LIST_ERROR
])
A More Complex Form to Handle Uniqueness Validation
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