pea - The tiniest green vegetable.

pea is a minimal BDD framework for python, in the style of ruby's cucumber and python's lettuce. It aims to help you write the same kind of tests - but in straight-up python code, without all the parsing and indirection and other hoops to jump through. It's a lot like ruby's coulda.

Benefits of cucumber-style testing include:

• You write your tests in clear, english language without inline code
• Your tests are human-readable, and hopefully human-editable
• You can re-use steps with confidence, because they all do exactly what they say on the tin

Benefits of pea over lettuce, cucumber, etc:

• It's a really trivial library (thus the name). It doesn't do very much, so it probably doesn't have many bugs

• Your features are just python code:

  • No "BDD language parser" needed
  • No regular expressions
  • Stack traces make sense
  • Syntax highlighting
  • You can use ctags to jump between test & implementation, as well as for method completion
  • Managing and renaming functions is much easier than managing regexes
  • You can use whatever abstractions you like
  • You can use rich python objects as arguments, instead of parsing strings

• It doesn't need its own test runner; so you can just use nose to run it alongside your unit tests

So how do I use it?

Here's a minimal example:

from pea import *

@step
def I_go_to_the_store():
    world.location='store'
    world.cart = []

@step
def I_buy_some(item):
    world.cart.append(item)

@step
def I_go_home():
    world.location = 'home'

@step
def I_have_some_delicious(item):
    assert item in world.cart
    world.assertEquals(world.location, 'home')

# --------------------

class TestShopping(TestCase):
    def test_buying_some_peas(self):

        Given.I_go_to_the_store()
        When.I_buy_some('peas')
        And.I_go_home()
        Then.I_have_some_delicious('peas')

... and when you run it (with nosetests, in verbose mode):

Typically you would put your steps in a separate python module (or many), but it's your choice.

Basics:

• @step adds your function to pea's registry of steps, which allows them to be called via Given, When, And, and Then.
• To re-use a step from inside another step, just call the function!

Stuff to remember:

• Make sure you inherit from pea.TestCase (and call super from setUp/tearDown), as it takes care of resetting the world between tests.
• You can use TestCase assertion methods on the world, too
  • e.g. world.assertEquals(expected, actual)

Pea works well with rednose