behaviour driven infrastructure

BehaviourDriven

InfrastructureLindsay Holmwood

DevOps

Behaviour Driven

Development

Behaviour Driven

Infrastructure?

What is a behavioural test?

origins

Test Driven Development

write test

write testrun test

write testrun test

test fails

write testrun test

test fails

make test pass

write testrun test

test fails

make test pass

refactor

unit tests

input/outputof

functions

result = bar(foo)assert(result, true)

xUnit

a reaction to test focus

Behavior Driven Development

testing the

flow of data in a system

testing the

flow of data in a system

test auser canperform atask

make a donationsearch for productcheckout cart

verifying a business’sfunctional

requirementsare met

underlying

implementation isirrelevant

to the business

underlying

implementation isirrelevant

to the business

Business: “assert(bar(foo),true)?”Tech: “Yes”Business: “Great”

Business: “assert(bar(foo),true)?”Tech: “Yes”Business: “Great”

Business: “Can I search for things?”Tech: “Yes”Business: “Great”

functionis importantfunctionis important

implementationis not

implementationis not

verifying a business’sfunctional

requirementsare met

integration testsacceptance testsintegration testsacceptance tests

“outside-in tests”“outside-in tests”

executable specificationexecutable specification

written in

spoken languagewritten in

spoken language

so the business understands what it is

paying for

so the business understands what it is

paying for

Enough business touchy-feely mumbo

jumbo!

I thought this was a

Behaviour Driven

Infrastructure talk?

I thought this was a

Behaviour Driven

Infrastructure talk?

Infrastructure as code

“The ‘Infrastructure’ is an application, a long running process with inputs, outputs and state.”

- Andrew Schafer, 2009http://bit.ly/he3HBt

an abstractionan abstraction

infrastructureis the

application

daemonsare the

libraries

configuration managementis the

programming language

infrastructureis

built with code

code without testsis

bad

code without testsis

evilevil

Why?

You can’t verify that your system works.

Behaviour Driven

Infrastructure

Taking BDD

principals & tools

Taking BDD

principals & tools

Adapting them to

infrastructure development

Show me the

tools!

Cucumber

Executable format for software specifications

Tool to execute that specification

Terminology

featureis a

module of common functionality

Feature: Google search To increase her knowledge A user Needs a search interface To discover information

featurehas many

scenarios

Feature: Google search To increase her knowledge A user Needs a search interface To discover information

Scenario: Home page When I visit "http://google.com.au/" And I fill in "q" with "great balls of fire" Then I should see "great balls of fire"

scenariohas many

steps

Given

When

Then

And*

stepsare like

unit tests

they mapto

blocks of code

Feature: Google search To increase her knowledge A user Needs a search interface To discover information

Scenario: Home page When I visit "http://google.com.au/" And I fill in "q" with "great balls of fire" Then I should see "great balls of fire"

When /^I visit "([^"]*)"$/ do |location| # codeend

When /^I fill in "([^"]*)" with "([^"]*)"$/ do |input, value| # codeend

Then /^I should see "([^"]*)"$/ do |string| # codeend

When /^I visit "([^"]*)"$/ do |location| visit(location)end

When /^I fill in "([^"]*)" with "([^"]*)"$/ do |input, value| fill_in(input, :with => value)end

Then /^I should see "([^"]*)"$/ do |string| response.body.should match(string)end

blocks of codeare like

unit tests

∴ scenariois a

serial execution of unit tests

Installing

$ apt-get install rubygems $ gem install cucumber

Using

$ apt-get install rubygems $ gem install cucumber

$ apt-get install rubygems $ gem install cucumber$ mkdir -p project/features/steps$ cd project

Testing Workflow

write test

write testrun test

write testrun test

test fails

write testrun test

test fails

make test pass

write testrun test

test fails

make test pass

refactor

$ apt-get install rubygems $ gem install cucumber$ mkdir -p project/features/steps$ cd project$ vim features/site.feature

Feature: Google search To increase her knowledge A user Needs a search interface To discover information

Scenario: Home page When I visit "http://google.com.au/" And I fill in "q" with "great balls of fire" Then I should see "great balls of fire"

$ apt-get install rubygems $ gem install cucumber$ mkdir -p project/features/steps$ cd project$ vim features/site.feature$ cucumber features/site.feature$ vim features/steps/site_steps.rb

$ apt-get install rubygems $ gem install cucumber$ mkdir -p project/features/steps$ cd project$ vim features/site.feature$ cucumber features/site.feature$ vim features/steps/site_steps.rb$ cucumber features/site.feature

Implications

Continuous Integration

Test server builds

Execute tests

on commit to config management

What environments are the tests run against?

UAT?

Staging?Production?

Destructive tests?

Fixtures

Setup / TeardownPattern

A/B testing

Migration to config management

Continuous Integration&

Monitoring Systems

build

testnotify

deploy

build

testnotify

deploy

testnotify

We’ve been asking the wrong questions

pingconnect

is the host up?is the service available?

is the host up?is the service available?

misconfiguration, bugs triggered by user data, hacked

network stack up

but otherwise broken

Why should I care?

“Nagios checks already do this!”

Cucumber

provides a framework

to phrase questions

Given

When

Then

Lowers the barrier of entry to

writing good checks

Caveat:

You need a firm grasp of language

Feature: Candy Store Wooooooooo!

Scenario: Lollipops When I fly to the moon Then I should see monkeys

Feature: Candy Store Wooooooooo!

Scenario: Lollipops When I fly to the moon Then I should see monkeys

completely valid,

completely useless

Cucumber

provides a common

specification format

dev & ops can share

Cucumber

provides a common

specification format

IT & business can share

Duplication of tests

Development

Production

Cucumber featuresare librarised tests

Cucumber featuresare librarised tests

Same specificationSame specification

Different implementationDifferent implementation

Where to from here?

Write more code.

Patterns.

Expand the library of tests.

Explain to your friends, colleagues, family, pets

these ideas.

Discuss!Thank you.

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