Behave BDD Skill

Core Patterns

Feature File (features/login.feature)

Feature: User Login
  As a registered user
  I want to log into the application

  Background:
    Given I am on the login page

  Scenario: Successful login
    When I enter "user@test.com" as email
    And I enter "password123" as password
    And I click login
    Then I should see the dashboard
    And the welcome message should say "Welcome"

  Scenario: Invalid credentials
    When I enter "wrong@test.com" as email
    And I enter "wrong" as password
    And I click login
    Then I should see error "Invalid credentials"

  Scenario Outline: Login with various users
    When I enter "<email>" as email
    And I enter "<password>" as password
    And I click login
    Then I should see "<result>"

    Examples:
      | email          | password | result    |
      | admin@test.com | admin123 | Dashboard |
      | bad@test.com   | wrong    | Error     |

Step Definitions (features/steps/login_steps.py)

from behave import given, when, then
from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC

@given('I am on the login page')
def step_on_login(context):
    context.browser.get(context.base_url + '/login')

@when('I enter "{text}" as email')
def step_enter_email(context, text):
    el = context.browser.find_element(By.ID, 'email')
    el.clear()
    el.send_keys(text)

@when('I enter "{text}" as password')
def step_enter_password(context, text):
    el = context.browser.find_element(By.ID, 'password')
    el.clear()
    el.send_keys(text)

@when('I click login')
def step_click_login(context):
    context.browser.find_element(By.CSS_SELECTOR, 'button[type="submit"]').click()

@then('I should see the dashboard')
def step_see_dashboard(context):
    WebDriverWait(context.browser, 10).until(
        EC.url_contains('/dashboard')
    )
    assert '/dashboard' in context.browser.current_url

@then('I should see error "{msg}"')
def step_see_error(context, msg):
    error = WebDriverWait(context.browser, 5).until(
        EC.visibility_of_element_located((By.CSS_SELECTOR, '.error'))
    )
    assert msg in error.text

Environment Hooks (features/environment.py)

from selenium import webdriver

def before_all(context):
    context.base_url = 'http://localhost:3000'

def before_scenario(context, scenario):
    context.browser = webdriver.Chrome()
    context.browser.implicitly_wait(10)

def after_scenario(context, scenario):
    if scenario.status == 'failed':
        context.browser.save_screenshot(f'screenshots/{scenario.name}.png')
    context.browser.quit()

Tags

@smoke
Feature: Login
  @critical
  Scenario: ...

behave --tags=@smoke
behave --tags="@smoke and not @slow"

Setup: pip install behave selenium

Run: behave or behave features/login.feature

Cloud Execution on TestMu AI

Set environment variables: LT_USERNAME, LT_ACCESS_KEY

# environment.py
from selenium import webdriver
import os

def before_scenario(context, scenario):
    lt_options = {
        "user": os.environ["LT_USERNAME"],
        "accessKey": os.environ["LT_ACCESS_KEY"],
        "build": "Behave Build",
        "name": scenario.name,
        "platformName": "Windows 11",
        "video": True,
        "console": True,
        "network": True,
    }
    options = webdriver.ChromeOptions()
    options.set_capability("LT:Options", lt_options)
    context.driver = webdriver.Remote(
        command_executor=f"https://{os.environ['LT_USERNAME']}:{os.environ['LT_ACCESS_KEY']}@hub.lambdatest.com/wd/hub",
        options=options,
    )

Report: behave --format json -o report.json

Deep Patterns

See reference/playbook.md for production-grade patterns:

Section	What You Get
§1 Project Setup	behave.ini, project structure, dependencies
§2 Feature Files	Gherkin with Scenario Outline, data tables, Background
§3 Step Definitions	Type registration, API steps, common steps with PyHamcrest
§4 Environment Hooks	before_all/scenario/feature, screenshot on failure, DB isolation
§5 Page Objects	BasePage with waits, LoginPage, reusable components
§6 Fixtures & Test Data	DatabaseHelper, transaction rollback, JSON data loader
§7 LambdaTest Integration	Remote browser creation, cloud capabilities
§8 CI/CD Integration	GitHub Actions with Postgres, Selenium, Allure reports
§9 Debugging Table	12 common problems with causes and fixes
§10 Best Practices	14-item BDD testing checklist