Inherit one story from another simply

You can break most software down into a series of individual linear behavioral stories.

However, software stories naturally branch. In order to send an email or delete an email you must first always log in.

While it would be possible to write out each individual story for every possible branch, this would result in a story suite that is WET instead of DRY and that creates a maintenance headache.

Story inheritance allows you to base stories on other stories.

The base story given preconditions and parameters will be used while the child story given preconditions will override them.

The steps of the parent stories, if they have any steps, will be executed before the child story steps.

example.story:

Login:
  about: Simple log in.
  with:
    username: AzureDiamond
    password: hunter2
  given:
    url: /loginurl
    files:
      a.txt: a
      b.txt: b
  steps:
  - Fill form:
      username: (( username ))
      password: (( password ))
  - Click: login


Log in on another url:
  about: Alternate log in URL.
  based on: login
  given:
    url: /alternativeloginurl

Log in as president:
  about: For stories that involve Trump.
  based on: login
  with:
    username: DonaldTrump
    password: iamsosmrt

engine.py:

from hitchstory import BaseEngine, GivenDefinition, GivenProperty
from strictyaml import Map, Int, Str, MapPattern, Optional


class Engine(BaseEngine):
    given_definition = GivenDefinition(
        url=GivenProperty(schema=Str()),
        files=GivenProperty(
            schema=MapPattern(Str(), Str()),
            inherit_via=GivenProperty.REPLACE,
        ),
    )

    def set_up(self):
        print("visit {0}".format(self.given['url']))

        for filename, content in self.given.get("files", {}).items():
            print("{}: {}".format(filename, content))

    def fill_form(self, **textboxes):
        for name, text in sorted(textboxes.items()):
            print("with {0}".format(name))
            print("enter {0}".format(text))

    def click(self, item):
        print("clicked on {0}".format(item))

With code:

from engine import Engine
from hitchstory import StoryCollection
from pathlib import Path
from ensure import Ensure

collection = StoryCollection(Path(".").glob("*.story"), Engine())

Original story

collection.named("Login").play()

Will output:

RUNNING Login in /path/to/working/example.story ... visit /loginurl
a.txt: a
b.txt: b
with password
enter (( password ))
with username
enter (( username ))
clicked on login
SUCCESS in 0.1 seconds.

Override given

collection.named("Log in on another url").play()

Will output:

RUNNING Log in on another url in /path/to/working/example.story ... visit /alternativeloginurl
a.txt: a
b.txt: b
with password
enter (( password ))
with username
enter (( username ))
clicked on login
SUCCESS in 0.1 seconds.

Override parameters

collection.named("Log in as president").play()

Will output:

RUNNING Log in as president in /path/to/working/example.story ... visit /loginurl
a.txt: a
b.txt: b
with password
enter (( password ))
with username
enter (( username ))
clicked on login
SUCCESS in 0.1 seconds.

Only children

print('\n'.join([
    story.name for story in collection.only_uninherited().ordered_by_file()
]))

Will output:

Log in on another url
Log in as president

Executable specification

Documentation automatically generated from simple-inheritance.story storytests.