@initiate

Sometimes high-level wrapping stories consist from inner stories completely. In that case it's tedious to copy-paste steps definition into constructor arguments. To reduce level of boilerplace code in such cases, stories library provides @initiate decorator.

Principles

• All story steps would be used in class constructor arguments
• Only Story subclasses could be initiated
• Initiated Story class should not have step methods
• Initiated Story class should not have constructor

All story steps would be used in class constructor arguments

When you decorate story class with @initiate decorator, in addition to the __call__ method it would add __init__ method as well. Story steps would be used as names for constructor arguments.

@initiate__init__

>>> from stories import Story, I, initiate

>>> @initiate
... class Purchase(Story):
...     I.find_order
...     I.find_customer
...     I.persist_payment

>>> from stories import Story, I

>>> class Purchase(Story):
...     I.find_order
...     I.find_customer
...     I.persist_payment
...
...     def __init__(self, find_order, find_customer, persist_payment):
...         self.find_order = find_order
...         self.find_customer = find_customer
...         self.persist_payment = persist_payment

Only Story subclasses could be initiated

Classes decorated by @initiate function should be subclasess of the Story. Otherwise, there is no steps to operate on.

>>> @initiate
... class Purchase:
...     def find_order(self, state):
...         state.order = self.load_order(state.order_id)
...
...     def find_customer(self, state):
...         state.customer = self.load_customer(state.customer_id)
...
...     def persist_payment(self, state):
...         self.create_payment(state.order_id, state.customer_id)
Traceback (most recent call last):
  ...
_stories.exceptions.StoryError: @initiate can decorate Story subclasses only

Initiated Story class should not have step methods

@initiate decorator does not allow to mix step methods with nested stories on initiated classes. Usually, story steps defined by methods expects some additional dependencies to be passed in the constructor.

>>> from stories import Story, I, initiate

>>> @initiate
... class Purchase(Story):
...     I.find_order
...     I.find_customer
...     I.persist_payment
...
...     def find_order(self, state):
...         state.order = self.load_order(state.order_id)
Traceback (most recent call last):
  ...
_stories.exceptions.StoryError: Story decorated by @initiate can not have step methods

Initiated Story class should not have constructor

>>> from stories import Story, I, initiate

>>> @initiate
... class Purchase(Story):
...     I.find_order
...     I.find_customer
...     I.persist_payment
...
...     def __init__(self):
...         ...
Traceback (most recent call last):
  ...
_stories.exceptions.StoryError: Story decorated by @initiate can not have constructor defined

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