python - 如何针对 Django 数据迁移运行测试？

Question

使用 documentation 中的以下示例:

def combine_names(apps, schema_editor):
    Person = apps.get_model("yourappname", "Person")
    for person in Person.objects.all():
        person.name = "%s %s" % (person.first_name, person.last_name)
        person.save()

class Migration(migrations.Migration):    
    dependencies = [
        ('yourappname', '0001_initial'),
    ]    
    operations = [
        migrations.RunPython(combine_names),
    ]

我将如何针对此迁移创建和运行测试，以确认数据已正确迁移？

Answer 1

我正在做一些谷歌来解决同样的问题，并发现 an article 为我钉在钉子上的锤子，似乎没有现有答案那么笨拙。所以，把它放在这里以防它帮助其他人。

提出了 Django 的 TestCase 的以下子类:

from django.apps import apps
from django.test import TestCase
from django.db.migrations.executor import MigrationExecutor
from django.db import connection


class TestMigrations(TestCase):

    @property
    def app(self):
        return apps.get_containing_app_config(type(self).__module__).name

    migrate_from = None
    migrate_to = None

    def setUp(self):
        assert self.migrate_from and self.migrate_to, \
            "TestCase '{}' must define migrate_from and migrate_to     properties".format(type(self).__name__)
        self.migrate_from = [(self.app, self.migrate_from)]
        self.migrate_to = [(self.app, self.migrate_to)]
        executor = MigrationExecutor(connection)
        old_apps = executor.loader.project_state(self.migrate_from).apps

        # Reverse to the original migration
        executor.migrate(self.migrate_from)

        self.setUpBeforeMigration(old_apps)

        # Run the migration to test
        executor = MigrationExecutor(connection)
        executor.loader.build_graph()  # reload.
        executor.migrate(self.migrate_to)

        self.apps = executor.loader.project_state(self.migrate_to).apps

    def setUpBeforeMigration(self, apps):
        pass

他们提出的一个示例用例是:

class TagsTestCase(TestMigrations):

    migrate_from = '0009_previous_migration'
    migrate_to = '0010_migration_being_tested'

    def setUpBeforeMigration(self, apps):
        BlogPost = apps.get_model('blog', 'Post')
        self.post_id = BlogPost.objects.create(
            title = "A test post with tags",
            body = "",
            tags = "tag1 tag2",
        ).id

    def test_tags_migrated(self):
        BlogPost = self.apps.get_model('blog', 'Post')
        post = BlogPost.objects.get(id=self.post_id)

        self.assertEqual(post.tags.count(), 2)
        self.assertEqual(post.tags.all()[0].name, "tag1")
        self.assertEqual(post.tags.all()[1].name, "tag2")