Behave

behave is behavior-driven development, Python style.

Behavior-driven development (or BDD) is an agile software development technique that encourages collaboration between developers, QA and non-technical or business participants in a software project.

behave uses tests written in a natural language style, backed up by Python code.

First, install *behave*.

Now make a directory called "features/". In that directory create a file called "example.feature" containing:

# -- FILE: features/example.feature
Feature: Showing off behave

  Scenario: Run a simple test
    Given we have behave installed
     When we implement 5 tests
     Then behave will test them for us!

Make a new directory called "features/steps/". In that directory create a file called "example_steps.py" containing:

# -- FILE: features/steps/example_steps.py
from behave import given, when, then, step

@given('we have behave installed')
def step_impl(context):
    pass

@when('we implement {number:d} tests')
def step_impl(context, number):  # -- NOTE: number is converted into integer
    assert number > 1 or number == 0
    context.tests_count = number

@then('behave will test them for us!')
def step_impl(context):
    assert context.failed is False
    assert context.tests_count >= 0

Run behave:

$ behave
Feature: Showing off behave # features/example.feature:2

  Scenario: Run a simple test          # features/example.feature:4
    Given we have behave installed     # features/steps/example_steps.py:4
    When we implement 5 tests          # features/steps/example_steps.py:8
    Then behave will test them for us! # features/steps/example_steps.py:13

1 feature passed, 0 failed, 0 skipped
1 scenario passed, 0 failed, 0 skipped
3 steps passed, 0 failed, 0 skipped, 0 undefined

Now, continue reading to learn how to get the most out of behave. To get started, we recommend the tutorial and then the feature testing language and api references.

More Information

• behave documentation: latest edition, stable edition, PDF
• behave.example: Behave Examples and Tutorials (docs, executable examples).
• changelog (latest changes)