Django TestCase on form validation fails even tough input is 有效

Question

如标题中所述，当我使用 FormView 时，我有一个可以正确验证的表单。然而，当我今天开始编写测试时相同的输入在 TestCase 中失败，我收到以下错误：

{'programming_language': ['Select a valid choice. That choice is not one of the available choices.']}

这些是我正在使用的模型、表单、视图和测试

# models.py
from django.db import models


class Tag(models.Model):

    name = models.CharField(max_length=40, unique=True)

class ProgrammingLanguage(models.Model):

    name = models.CharField(max_length=40, unique=True)

class Snippet(models.Model):

    title = models.CharField(max_length=40)
    programming_language = models.ForeignKey(ProgrammingLanguage, on_delete=models.CASCADE)
    creation_date = models.DateTimeField(auto_now_add=True)
    explanation = models.TextField()
    code = models.TextField()
    tags = models.ManyToManyField(Tag)


# forms.py  
from django import forms
from django.utils.translation import gettext_lazy as _

from .models import Snippet

class SnippetForm(forms.ModelForm):

    class Meta:
        model = Snippet
        exclude = ["creation_date"]

# views.py
from django.urls import reverse_lazy
from django.views import generic
from .models import Snippet
from .forms import SnippetForm

class SnippetFormView(generic.FormView):
    template_name = "snippets/snippet_form.html"
    form_class = SnippetForm
    success_url = reverse_lazy("snippets")

    def form_valid(self, form):
        # for testing purposes
        print(form.cleaned_data)
        form.save()
        return super().form_valid(form)

# test_forms.py
from django.test import TestCase

from snippets.forms import SnippetForm
from snippets.models import ProgrammingLanguage, Tag, Snippet

class SnippetFormTestCase(TestCase):

    @classmethod
    def setUpTestData(cls):
        ProgrammingLanguage.objects.create(name="Javascript")
        Tag.objects.create(name="website")

    def test_forms(self):
        form = SnippetForm({
            'title': 'Test snippet title',
            'programming_language': ProgrammingLanguage.objects.get(pk=1),
            'code': 'code here',
            'explanation': 'explanation here',
            'tags': Tag.objects.all()
        })
        # calling is valid to get cleaned_data and original data 
        form.is_valid()
        print(form.data)
        print(form.cleaned_data)
        self.assertEqual(form.errors, {})

这是cleaned_data我在视图中得到的：

{'title': 'Test snippet title', 'programming_language': <ProgrammingLanguage: Javascript>, 'explanation': 'explanation here', 'code': 'code here', 'tags': <QuerySet [<Tag: website>]>}

这是我在测试中得到的数据和 cleaned_data:

# data
{'title': 'Test snippet title', 'programming_language': <ProgrammingLanguage: Javascript>, 'code': 'code here', 'explanation': 'explanation here', 'tags': <QuerySet [<Tag: website>]>}
# cleaned_data
{'title': 'Test snippet title', 'explanation': 'explanation here', 'code': 'code here', 'tags': <QuerySet [<Tag: website>]>}

为什么 ProgrammingLanguage 在测试期间是无效的选择，但在使用网站时有效？

Answer 1

在你的测试中试试这个：

form = SnippetForm({
        'title': 'Test snippet title',
        'programming_language': 1, #ProgrammingLanguage.objects.get(pk=1),
        'code': 'code here',
        'explanation': 'explanation here',
        'tags': Tag.objects.all()
    })

当将表单用于将主键作为其字段之一的模型时，您使用此类字段的 pk 值将表单绑定到数据，而不是模型实例。

这就是 FormView 在幕后所做的事情。这就是为什么您的测试失败而视图工作正常的原因。

还要确保您的编程语言 pk 是 1.

Django TestCase on form validation fails even tough input is 有效

Django TestCase on form validation fails even tough input is valid

python

django

django-forms

django-testing