test_models.py

from product.models import Category

def test_filter_category(db):
    Category.objects.create(name="Books")
    assert Category.objects.filter(name="Books").exists()

def test_update_category(db):
    category = Category.objects.create(name="Books")
    category.name = "DVDs"
    category.save()
    category_from_db = Category.objects.get(name="DVDs")
    assert category_from_db.name == "DVDs"