django数据库迁移migration实现

from django.db import models class Item(models.Model):     text=models.TextField(default='')

'''from django.test import TestCase # Create your tests here. class Smokeclass(TestCase):     def test_bad_maths(self):         self.assertEquals(1+1,3)''''' from  django.urls import  resolve from  django.test import  TestCase from lists.views import  home_page from django.http import  HttpRequest from lists.models import Item class HomePageTest(TestCase):     def test_root_url_resolve_to_home_page_view(self):         found=resolve('/')         # resolve函数是django内部使用的函数，用于解析url，         # 并且将其映射到相应的视图函数上，检查网站根路径时"/"，         # 是否能找到home_page函数         self.assertEquals(found.func,home_page)     def test_home_page_returns_correct_html(self):         request=HttpRequest()         # 创建httprequest对象，用户在浏览器中请求网页时         # django看到的就是httprequest对象         response=home_page(request)         # 把对象传给home_page视图         html=response.content.decode('utf8')         # 提取content，得到结果是原始的字节，即发个用户         # 浏览器的0和1，随后调用.decode(),把原始字节         # 转换成发给用户的html字符串         self.assertTrue(html.startswith(''))         self.assertIn('',html)         self.assertTrue(html.endswith('))  self.assertTemplateUsed(response,'home.html')     def test_user_home_template(self):         response=self.client.get('/')         self.assertTemplateUsed(response,'home.html')     def test_can_save_a_POST_request(self):         response=self.client.post('/',data={'item_text':'a new list item'})         self.assertIn('a new list item',response.content.decode())         self.assertTemplateUsed(response, 'home.html') class ItemModelTest(TestCase):     def test_saving_and_retrieving_items(self):         first_item=Item()         first_item.text="the first list item"         first_item.save()         second_item = Item()         second_item.text = "the second list item"         second_item.save()         saved_items=Item.objects.all()         self.assertEquals(saved_items.count(),2)         first_saved_item=saved_items[0]         second_saved_item=saved_items[1]         self.assertEquals(first_saved_item.text,'the first list item')         self.assertEquals(second_saved_item.text, 'the second list item')

python manage.py makemigrations