BDDBEHAVIOUR DRIVEN DEVELOPMENT

NO INTEGRATION TESTTWO UNIT TESTS PASSED

WOULDN’T IT BE GREAT?

• Clear requirements

• Measurable acceptance criteria

• Documentation of existing functionality

• Confidence everything works?

“WHAT’S THE PURPOSE OF MEANING?”

WHAT IS BDD

A. A way to structure unit tests

B. Unit tests with a new name

C. Executable specifications

D. Automated Test Scenarios

FORMB.D.D.

Given [initial state]

When [do stuff]

Then [result]

B.D.D.

EXAMPLE

Feature: Green Bottles

Scenario: Should fall from the wall

Given 100 green bottles are standing on the wall

When 1 green bottle accidentally falls

Then there are 99 green bottles standing on the wall

“MAKE IT RUN”THE CODE

module.exports = English.library()

.given("$NUM green bottles are standing on the wall", function(number, next) {

wall = new Wall(number);

next();

})

.when("$NUM green bottle accidentally falls", function(number, next) {

wall.fall(number);

next();

})

.then("there are $NUM green bottles standing on the wall", function(number, next) {

assert.equal(number, wall.bottles);

next();

});

EXECUTE IT!

macbookpro:yadda-tutorial machiel$ mocha --reporter spec test.js

100 Green Bottles Should fall from the wall ✓ Given 100 green bottles are standing on the wall ✓ When 1 green bottle accidentally falls ✓ Then there are 99 green bottles standing on the wall

3 passing (34ms)

DONEC QUIS NUNC

ALTERNATIVE: CODE DECORATION

describe("A suite", function() {

it("contains spec with an expectation", function() {

expect(true).toBe(true);

});

});

A suitecontains spec with an expectation

DIVIDE ET IMPERA

ONE SCENARIO TO RULE THEM ONE

SCENARIO

SERVER SIDE TEST

UI TEST

MULTI BROWSER

TEST

PERFORMANCE TEST

“COMPARISON IS THE THIEF OF JOY”BDD VS TDD

• Unit

• One function or class

• language of the system

• fine grained

• Behaviour

• the whole system

• language of the user

• coarse

BENEFITS

USER LEVEL TESTS

• Test linked to Story

• Done or not

• Technology agnostic

• Multiple usages

• Refactor friendly

CLARITY SECURITYSPEED

BDD IN A NUTSHELL

LIBRARIES

Pure BDD in JS https://github.com/acuminous/yadda

Yadda in crossbrowser testing https://github.com/kjelloe/Yadda-WebdriverJS