Django: Set many-to-many value to a model - django

Question

I am trying to test my Models Project, Category and Tag. I'm running into an issue when trying to add tags to my project model.
It won't allow me to do it in the Project model itself for eg.
self.project = Project.objects.create(
...
tags=Tag.objects.create("HTML5"),
)
Django docs suggest the I do it as below. However I can't "add" the Tag without saving the model and I can't save the model without adding the Tag
Tests
class ProjectTests(TestCase):
def setUp(self):
self.tag = Tag.objects.create(name="HTML5")
self.project = Project(
title="Oaks on Main Shopping Center",
url="www.oaksonmain.co.za",
image=SimpleUploadedFile(
name="test-image.jpg",
content=open(
"static\\images\\test_images\\florian-olivo-4hbJ-eymZ1o-unsplash (1).jpg", "rb"
).read(),
content_type="image/jpeg",
),
description="Beautiful website created for Oaks on Main Shopping Center in Knysna!",
category=Category.objects.create(name="Website"),
)
self.project.save() <- Problem here
self.project.tags.add(self.tag) <- Problem here
def test_project_model(self):
self.assertEqual(f"{self.project.title}", "Oaks on Main Shopping Center")
self.assertEqual(f"{self.project.url}", "www.oaksonmain.co.za")
self.assertEqual(
f"{self.project.description}",
"Beautiful website created for Oaks on Main Shopping Center in Knysna!",
)
self.assertEqual(self.tags.count(), 3)
self.assertEqual(self.category.count(), 1)
self.assertEqual(self.image.count(), 1)
def test_project_listview(self):
resp = self.client.get(reverse("index"))
self.assertEqual(resp.status_code, 200)
self.assertContains(resp, self.project.title)
self.assertTemplateUsed(resp, "page/index.html")
Models
class Project(models.Model):
class Meta:
ordering = ["-id"] # Always show latest projects first
verbose_name_plural = "Projects"
title = models.CharField(max_length=50)
url = models.URLField()
image = models.ImageField(upload_to=f"{title}/")
description = models.TextField()
category = models.ForeignKey("Category", on_delete=models.PROTECT, related_name="categories")
tags = models.ManyToManyField("Tag", verbose_name="tags")
def __str__(self):
return self.title
def get_absolute_url(self):
return reverse("index")
class Category(models.Model):
class Meta:
ordering = ["name"]
verbose_name_plural = "Categories"
name = models.CharField(max_length=20)
def __str__(self):
return self.name
def get_absolute_url(self):
return reverse("index")
class Tag(models.Model):
class Meta:
ordering = ["name"]
verbose_name_plural = "Tags"
name = models.CharField(max_length=10)
def __str__(self):
return self.name
def get_absolute_url(self):
return reverse("index")

Answer 1

You can first save the tag or the model object, and then later you link the tag as (one of) tags of that Project, so:
html5_tag, __ = Tag.objects.get_or_create(name='HTML5')
self.project = Project.objects.create(
# no tags=…
)
self.project.tags.add(html5_tag)
Your ImageField also should work with a callable for the upload_to=… parameter, so:
class Project(models.Model):
# …
def upload_image(self, filename):
return f'{self.title}/{filename}'
image = models.ImageField(upload_to=upload_image)
# …