如何将起始序列号传递给 Django factory_boy 工厂？

Question

factory_boy 默认为1 用于序列。如何传递一个数字以用作不同的起始数字？我可以继承_setup_next_sequence() 方法，但我怎样才能给它一个变量来使用呢？

# File: models.py
from django.db import models

class Book(models.Model):
    title = models.CharField(max_length=100)

# File: factories.py
from .models import Book
import factory

class BookFactory(factory.Factory):
  FACTORY_FOR = BookModel  
  title = factory.Sequence(lambda n: u'Title #{}'.format(n))

  @classmethod
  def _setup_next_sequence(cls):      
      # Instead of defaulting to starting with number 1, start with starting_seq_num.
      # But how do I set starting_seq_num?
      return starting_seq_num

# File: make_data.py
from factories import BookFactory

# somehow set starting sequence number here?

BookFactory().create()

我正在使用 factory_boy 1.2.0（来自 pip install factory_boy）
factory_boy 代码：https://github.com/dnerdy/factory_boy

Answer 1

除了Rob Bednark的回答

我们可以使用reset_sequence() 函数，它会将计数器重置为特定值。

# File: make_data.py
import factories

factories.BookFactory.reset_sequence(100)
my_book = factories.BookFactory().create()
print(my_book.title) # Title #100

Answer 2

更新：factory_boy 现在处理它！

在最新版本的factory_boy（2.8.1 至今）中，现在可以将force the sequence counter 定义为一个值：

在每次调用的基础上强制该值

为了对特定的Factory 实例化强制计数器，只需将值传递给 __sequence=42参数：

class AccountFactory(factory.Factory):
        class Meta:
            model = Account
        uid = factory.Sequence(lambda n: n)
        name = "Test"

然后在控制台中：

>>> obj1 = AccountFactory(name="John Doe", __sequence=10)
>>> obj1.uid  # Taken from the __sequence counter
10
>>> obj2 = AccountFactory(name="Jane Doe")
>>> obj2.uid  # The base sequence counter hasn't changed
1

并且还可以将计数器重置为特定值：

>>> AccountFactory.reset_sequence(42)
>>> AccountFactory().uid
42
>>> AccountFactory().uid
43

Answer 3

我找到了两种解决方法：

1. 使用模块变量
2. 使用类定义之外的类属性集

使用模块变量：

# File: factories.py
from .models import Book
import factory

starting_seq_num = 0

class BookFactory(factory.Factory):
  FACTORY_FOR = BookModel  
  title = factory.Sequence(lambda n: u'Title #{}'.format(n))

  @classmethod
  def _setup_next_sequence(cls):      
      # Instead of defaulting to starting with 0, start with starting_seq_num.
      return starting_seq_num

# File: make_data.py
import factories

factories.starting_seq_num = 100    
factories.BookFactory().create()

使用类定义之外的类属性集：

# File: factories.py
from .models import Book
import factory

class BookFactory(factory.Factory):
  # Note that starting_seq_num cannot be set here in the class definition,
  # because Factory will then pass it as a kwarg to the model's create() method
  # and cause an exception.  It must be set outside the class definition.
  FACTORY_FOR = BookModel  
  title = factory.Sequence(lambda n: u'Title #{}'.format(n))

  @classmethod
  def _setup_next_sequence(cls):      
      return getattr(cls, 'starting_seq_num', 0)

# File: make_data.py
from factories import BookFactory

BookFactory.starting_seq_num = 100
BookFactory().create()

Answer 4

第三种也是最简单的方法：

# File: factories.py
from .models import BookModel
import factory

class BookFactory(factory.Factory, starting_seq_num):
  FACTORY_FOR = BookModel  
  title = factory.Sequence(lambda n: u'Title #{}'.format(n + starting_seq_num))

# File: make_data.py
import factories

book = factories.BookFactory(512).create()  #Start with 512

我自己只是从 Factory Boy 开始，在 Python 方面也没有太多经验，所以我可能会遗漏一些东西，但你知道我要去哪里。为了更清楚，我想我实际上更喜欢它被关键字：

class BookFactory(factory.Factory, title_seq_start=-1):
...
book = factories.BookFactory(title_seq_start=512).create()