Mom's Guide to Behave (Python Behaviour Driven Development)

May 21, 2025

2 min read

Updated: May 22, 2025

“Understanding Python Behave with clarity and care — just like mom would explain.Because even moms can teach BDD — the Pythonic way!”

Behave is Python’s BDD framework that turns user stories into testable scenarios. Let’s break it down—Mom style!

What is Behave?

Consider Behave as a cookbook for testing your software. Similar to following a recipe to bake cookies, Behave allows you to write tests in simple language that outline how your software is expected to function. Behave is written in plain English,coded in python.Behave is like mom saying: ‘Sure, you can go out...’ But Python is quietly running checks on your location, money, and grades."

The Key Ingredients

Feature files: They are like Mom's recipe cards
1. Neatly written in plain English(Gherkins Language).
2. Easy to follow.
Ghekin's Cheat Sheet

Gherkin's Keyword	What Does it do?	Mom's Example
Feature	Describes what you are testing ?	Feature: Grocery Budget Management
Background	Common setup for all scenarios	Given I have $1000; And rent is paid
Scenario	A specific case or test example	Scenario: Buying veggies under budget
Given	Pre-condition or starting state	Given I have $200
When	The action you're testing	When I spend $150 on groceries.
Then	The expected result	Then I should be left with $50(hopefully!)
And/But	Add more steps to any part	And I buy milk; But I return the chips
@Tags	Labels or groups scenarios	@groceries, @rent, @utilities
Scenario Outline	Template to run the same test with different data

Guidelines for Writing Feature Files

Ensure all your feature files have a .feature extension - Just like every recipe needs a label!"
Begin with a Feature Title "Mark your jar before adding money!"
Craft Scenarios as Short Stories "Each dollar spent should tell a tale!"
Adopt Declarative Steps (Avoid Imperative) "Mom says what should happen, not how to do it!"
Utilize Background for Common Setup "Use Background like a family rule—establish it once, and let all scenarios adhere to it (unless an exception is needed)!"
Tag Scenarios for Organization."Label your money envelopes—savings, spending, emergencies!"

Step Definitions - These are the actual Python code that makes the steps work.Like the actual cooking instructions behind the recipe.

Guidelines for Writing Step definitions
1. Match the Gherkin Steps Exactly ."If the recipe says ‘1 cup sugar,’ don’t use salt!"
2.Use context to Share Data to use across steps."Like passing the grocery list between family members!"
3. Keep Steps Atomic (One Action per Step)."One chore at a time—no multitasking!"
4.Use Parameters {}for Flexibility."A good budget works with any number!"
5.Address Assertions Transparently."Verify the receipt before exiting the store!"