DevTeach12-betterspecs

Writing BetterDomain Oriented

Cucumber FeaturesAmir Barylko

• Architect

• Developer

• Mentor

• Great cook

• The one who’s entertaining you for the next hour!

Who am I?Better Cucumber Features

Behavior Driven Dev.

TextText

The rSpec Book

•Delivering late or over budget

•Delivering the wrong thing

• Unstable in production

• Costly to maintain

Why Projects Fail?Amir Barylko - Better Cucumber Features

• Unit Testing

• Integration Testing

• Acceptance Testing

Improve QualityAmir Barylko - Better Cucumber Features

• Implementing an application

• by describing its behavior

• from the perspective of the stakeholder

BDDAmir Barylko - Better Cucumber Features

Outside In ApproachAmir Barylko - Better Cucumber Features

BDD TDD

•Write a test before any line of code

•Write minimum amount of code to make the test pass

• Refactor code to eliminate “smells”

Test FirstAmir Barylko - Better Cucumber Features

Cucumber

• Business readable DSL

• Flush out requirements

• Documentation

• Automated testing

• Used by Cucumber, SpecFlow, jBehave

Gherkin DSLAmir Barylko - Better Cucumber Features

• Feature

• Scenario

• Given

•When

• Then

• And

• But

Gherkin KeywordsAmir Barylko - Better Cucumber Features

Feature: Listing projects As a user I Want to see the list of projects So I can choose one to see the details

Scenario: List all projects (steps here to implement scenario)

Scenario: No projects are available (steps here to implement scenario)

FeaturesAmir Barylko - Better Cucumber Features

Free text!

ScenarioAmir Barylko - Better Cucumber Features

Scenario: List all projects Given I'm logged in And I have some projects stored When I browse the projects Then I should see all of them listed

Step 1

Step 2

Step 3

Step 4

• Parse the feature

• Parse the scenario

• For each scenario

• Find a step implementation

• Execute the code

Running FeaturesAmir Barylko - Better Cucumber Features

•Matching regular expression

Matching StepAmir Barylko - Better Cucumber Features

Given I have some projects stored

Given /^I have some projects stored$/

Feature File

Step Def File

Given /^I have some projects stored$/ do

projects = 10.times { random_valid_project }

fake_response = create_response(projects)

FakeWeb.register_uri(....)

end

StepAmir Barylko - Better Cucumber Features

Plain Ruby!

Expressive Scenarios

• Readability

• Ubiquitous Language

• Consistent use of terminology

• Express natural business intent

• Avoid technical aspects

What we want?Amir Barylko - Better Cucumber Features

Imperative styleAmir Barylko - Better Cucumber Features

Scenario: Redirect user to originally requested page

Given a User "dave" exists with password "secret"

And I am not logged in

When I navigate to the home page

Then I am redirected to the login form

When I fill in "Username" with "dave"

And I fill in "Password" with "secret"

And I press "Login"

• Who needs the passwords?

• Tightly coupled to page implementation

• Lacks domain language

• Brittle tests

• Does not tell a story (boring)

What’s the problem?Amir Barylko - Better Cucumber Features

Declarative styleAmir Barylko - Better Cucumber Features

Scenario: Redirect user to originally requested page

Given I am an authenticated user

When I attempt to view restricted content

Then I am presented with a login form

When I authenticated with valid credentials

Then I should be shown the restricted content

• Imperative is associated to “how” to do it

•Declarative is associated to “what” we want

•Where’s the boundary?

Declarative vs ImperativeAmir Barylko - Better Cucumber Features

Too abstract?Amir Barylko - Better Cucumber Features

Scenario: The whole system

Given the system exists

When I use it

Then it should work, perfectly

• Steps may have some degree of repetition

• Because they start with the same “state”

• So they share the first X steps

Background stepsAmir Barylko - Better Cucumber Features

Scenario: Change Password

Given I am logged in

And I choose to change my password

When I enter a new password

Then my password should be changed

Scenario: Change Password with same credentials



When I enter the same password

Then I should see an error message explaining the problem

Similar scenariosAmir Barylko - Better Cucumber Features

Background: I want to change my password



Scenario: Change Password

When I enter a new password

Then my password should be changed

Scenario: Change Password with same credentials

When I enter the same password

Then I should see an error message explaining the problem

Create BackgroundAmir Barylko - Better Cucumber Features

• Sometimes data is hard to put in a step

• with multiple entries

Using TablesAmir Barylko - Better Cucumber Features

Scenario: Listing movies

Given the movie “Blazing saddles” released “7 Feb 1974”

And the movie “Young Frankenstein” released “15 Dec 1974”

And the movie “The Producers” released “10 Nov 1968”

• Do you really need the list?

Why the detail though?Amir Barylko - Better Cucumber Features


Given I have some movies stored

When I browse the list

Then I should see the complete collection

• Each scenario leaves the system in a particular state

• The state has to be cleaned up for the next scenario

• Otherwise it will “leak” into it

• One scenario should not depend on another

Leaky ScenariosAmir Barylko - Better Cucumber Features

• Use a framework to generate valid data

• FactoryGirl is a very good option

• FactoryGirl.create(:customer)

• FactoryGirl.create(:invalid_bank_accout)

• Faker will help you to generate fake data

Generating dataAmir Barylko - Better Cucumber Features

• Steps can have arguments

• Though regular expression they don’t always show intent

• And also we may need to “reuse” them

TransformsAmir Barylko - Better Cucumber Features

Steps with argumentsAmir Barylko - Better Cucumber Features

Given /^I search for a movie “([^"]*)”$/ do |name|

.... # some code here

end

Given /^I have a movie called “([^"]*)”$/ do |name|


end

Capture the argumentAmir Barylko - Better Cucumber Features

Given /^I search for a movie “(#{MOVIE_NAME})”$/ do |name|


end

MOVIE_NAME = Transform /^([^"]+)$/ do | movie_name |

movie_name.downcaseend

• Helpers are a great tool to encapsulate common functionality

• Or to help describe better our intention

• and to avoid looking at ugly code

HelpersAmir Barylko - Better Cucumber Features

• The World is created for each scenario

• Instance variables have to be set

• Instead we can use a helper method

• to store/create the resource

Current InstanceAmir Barylko - Better Cucumber Features

Helper ClassAmir Barylko - Better Cucumber Features

module ProjectHelper def current_project(project = nil) @current_project ||= project end def project_list_page @project_list_page ||= ProjectListPage.new end end

World(ProjectHelper)

Custom matchersAmir Barylko - Better Cucumber Features

RSpec::Matchers.define :match_stored_projects do match do |actual| actual == Project.all.map { ... } end

failure_message_for_should do |actual| "The projects in the page should match...\n" + "The page contains #{actual}' \n" + "But the storage contains #{@expected}" end

end

• The steps rely on the HTML implementation

• Searching for elements can be repetitive

• or ugly

• and not always show intention

Page ObjectsAmir Barylko - Better Cucumber Features

•

What can we do?Amir Barylko - Better Cucumber Features

Then /^I should see the complete list of projects$/ do actual = all(:css, "#projects tbody tr") .map { |tr| tr.all("td").map(&:text) } .map { |cells| ... } expected = Project.all.map { |p| ... } actual.should == expectedend

•

Abstraction!Amir Barylko - Better Cucumber Features

class ProjectListPage include PageObject def projects all(:css, "#projects tr"). drop(1). #drop the header map { |r| r.all(:css, 'td').map(&:text) }. map { |r| Project.new(...) } endend

•

Nicer stepsAmir Barylko - Better Cucumber Features

Then /^I should see the complete list of projects$/ do projects_page.list.should == stored_projectsend

HelperPage Object

•

With a custom matcherAmir Barylko - Better Cucumber Features

Then /^I should see the complete list of projects$/ do projects_page.should list_stored_projectsend

Custom Matcher

Summary

• Focus your scenarios on “what” not “how”

• Read about scenario outlines

• Follow “the Cucumber book” practices

• Learn more about page objects pattern

• Start with a simple project

Next stepsAmir Barylko - Better Cucumber Features

• Email: [email protected],

• Twitter : @abarylko

• Blog: http://orthocoders.com

•Website: http://maventhought.com

ResourcesAmir Barylko - Better Cucumber Features

Resources IIAmir Barylko - Better Cucumber Features

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