S(p)exy testing in Coffeescript and Node.js

Aaron Murray@WeAreFractal

Nicholas Vaidyanathan@SWVisionary

We’re glad you’re here!

But you obviously care about tests, so let’s talk about some terminology…

TDD, ATDD, BDD, DDD?That’s a lot of DD’s

• TDD = Test Driven Development – Development Methodology, write tests first, test using xUnit – make sure the code works

• ATDD = Acceptance Test Driven Development – business-readable, Team-driven, tests owned by client – make sure the features are correct

• BDD = Behavior Driven Development – Team-driven, “Should”, “Given, When, Then” – extends TDD and incorporates ATDD

• DDD = Domain Driven Design – outlines the idea of the Ubiquitous Language used between non-technical stakeholders and developers

Wait, DDD? Why?

• What does DDD have to do with BDD?• Proper architecture helps you

– set up smallest possible services– Focus on nouns and verbs– Describes behavior, which drives BDD process

• Testing IS Design!!!!

• GOOD ARCHITECTURE IS PIVOTAL TO SUCCESSFUL BDD!

In the beginning, there was TDD

• Test Driven Development – Rediscovered by Kent Beck @kentbeck

• Simple Process– Test– Code– Refactor

Tests looked like this

• http://junit.sourceforge.net/doc/cookbook/cookbook.htm

Then we came to ATDD

• http://testobsessed.com/wp-content/uploads/2011/04/atddexample.pdf

• TDD is a programming practice, not a testing technique.

• Acceptance Test Driven Development (ATDD) also involves creating tests before code

• tests represent expectations of behavior the software should have.

• team creates one or more acceptance-level tests for a feature before beginning work on it.

• team discusses tests and captures them when working with the business stakeholder(s) to understand a story on the backlog.

And BDD• Evolved out of established agile practices and is designed to make

them more accessible and effective for teams new to agile software delivery.

• Premises– Test method names should be sentences– A simple sentence template keeps test methods focused– An expressive test name is helpful when a test fails– “Behaviour” is a more useful word than “test”– Determine the next most important behaviour– Requirements are behaviour,too– BDD provides a “ubiquitous language” for analysis– Acceptance criteria should be executable

• http://dannorth.net/introducing-bdd/

BDD Breakdown

Business-readable output– Replacement/Extension for TDD at the Unit-testing level– Artifacts owned by developers (code)– Provides other stakeholders with reports after developers have done the work– Gspec, Spock, EasyB

Business-readable input– Based on Acceptance Testing – coarse-grained features – Artifacts owned by client– Stakeholder involvement before developers have done any work– Cucumber, FitNesse

Not exclusive – can and probably need to be combined

Fundamentally Two Types of BDD Tools

EasyB business-readable output

inputscenario "Two amounts with the same currencies are

added", { given "Two different amounts with the same

currencies", { money1 = new Money(12, "CHF") money2 = new Money(14, "CHF") expected = new Money(26, "CHF") } when "Add given amounts" , { result = money1.add(money2) } then "New amount is sum of two given ones", { result.equals(expected).shouldBe true }}… <<truncated>>

output

2 scenarios executed successfully.

Story: money

scenario Two amounts with the same currencies are added given Two different amounts with the same currencies when Add given amounts then New amount is sum of two given ones

scenario Two amounts with different currencies are added given Two amounts with different currencies when Add given amounts then Operation should fail

Step 1: write your featureAddition.feature

Feature: Addition In order to avoid silly mistakes As a math idiot I want to be told the sum of two numbers

Scenario: Add two numbers Given I have entered <input_1> into the calculator And I have entered <input_2> into the calculator When I press <button> Then the result should be <output> on the screen

Examples: | input_1 | input_2 | button | output | | 20 | 30 | add | 50 | | 2 | 5 | add | 7 | | 0 | 40 | add | 40 |

Step 2: step definitionCalculatorSteps.groovy

this.metaClass.mixin(cuke4duke.GroovyDsl)

Before() {    calc = new Calculator()}

Given(~"I have entered (\\d+) into the calculator") { int n ->    calc.push n}

When(~"I press (\\w+)") {op ->    result = calc.send(op)}

Then(~"the result should be (.*) on the screen") { int r ->    assert r == result}

Step 4: write code to make it passCalculator.groovy

class Calculator {    def numbers = []

    void push(number) {        numbers << number    }

    def send(operation) {        def result        switch (operation) {            case "add":                result = add()        }        numbers.clear()        result    }

    private def add() {        numbers.sum()    }}

BDD in Java/Coffeescript and Node

• Best available frameworks– Jasmine– Vows

• Comparison– http://stackoverflow.com/questions/4115492/java

script-bdd-vows-kyuri-vs-jasmine• So…

Introducing

• Built in Node.js natively• Written in CoffeeScript• Modular, clean architecture• Designed to dramatically simplify the BDD process• Provides an annotation based mechanism for

defining your tests

Example spec

Benefits

• Clean syntax• Doesn’t pollute global namespace• Flexibility

• Give it a try– https://github.com/wearefractal/spex

• LIVE DEMO