Moving away from legacy code with BDD

Moving away from legacy code

with BDD

Who?!

BDD Evangelist !

BDD Practice Manager @Inviqa !

Creator of Behat, Mink, PhpSpec2, Prophecy

!Contributor to Symfony2, Composer

!Host of the “Elephant in the Room”

podcast

This talk is about

• Solving purely technical “TCIAM” problem with agile business analysis and discovery processes

• Building a delivery strategy on the idea of constant change

• Real-life experience

This talk is not about

• Greenfield projects

• Solutions for everyone

• How to write code

This talk is not about

• Greenfield projects

• Maintenance-mode projects

• Solutions for everyone

• How to write code (well, mostly)

Legacy projects

How most developers see their next project

My next project

My next project

His actual next project

Agile, TDD, BDD, General QA, etc…

// TODO: refactor this later

Is it really that bad?

If the project can afford at least one full-time specialist on a payroll that whines how horrible this project is, then surely it did something right.

// TODO: refactor this later

// TODO: refactor this later

// TODO: refactor this later

This world is full of brilliant projects that nobody wants to whine about. Sadly, it’s often simply because there’s no one left to pay for that.

The truth is: You deliver value!

Just not as effectively as you could

// TODO: refactor this later

Agile, TDD, BDD, General QA, etc…

How?

Three options

1. Rewrite an entire application using “the right way”

2. Do functional refactoring

3. Do business-oriented rewrite using “BDD pipeline”

#1: Full Rewrite

#1: Full Rewrite

• Scrum / Kanban

• TDD / BDD / DDD / Pair-programming

• New everything

• Mirroring functionality

#1: Income

6 Months later…

#1: Almost there…

#1: Full Rewrite

Just spaghetti, please: 4 man years

Full London meal (TDD, BDD, Agile, QA): ??? man years

#2: FUNCTIONAL Refactoring

#2: Functional Refactoring

• Blackbox testing

• New routing

• New templating system

• Migration of model layer (MySQL -> Mongo)

#2: Income

6 Months later…

#2: Ta-da!!!

– Your client. (most likely)

“Exactly what did you do here?”

#3: BDD PIPELINEAKA Business-Oriented rewrite

Why do some legacy projects suck?

Cost

Time

Because of the cost of change

… Of change where?

Why do applications change?

Welcome to the wonderland

of Agile Business Analysis

Questionnaire

1. What is the goal and minimal valuable product?

2. What is the minimal set of features to support it?

3. Which features are more likely to change?

4. How fully those features should be implemented?

5. How to avoid gold plating?

“BDD Pipeline”

1. Impact Mapping

2. Feature Mapping

3. Prioritisation

4. Example Workshop

5. Full-stack BDD

1. What is the Goal & minimal valuable product?

Impact Mapping

– Gojko Adzic

“Impact mapping is a strategic planning technique that prevents organisations from getting lost

while building products and delivering projects, by clearly communicating assumptions, helping teams align their activities with overall business objectives and make better roadmap decisions.”

Four levels of Impact Map

1. Why? are we doing all this (rewrite)? What is the goal we’re trying to achieve?

2. Who? will be impacted by it?

3. How? can they help us to achieve the goal?

4. What? can we do to support them?

MVP

impactmapping.org

2. What is the minimal set of features to support it?

Feature Mapping

– Marcello Duarte

“Feature mapping is a backlog grooming technique. It is a graphical process which helps teams in finding features that are necessary to

support discovered MVP”

Three levels of feature map

1. What? is the minimal marketable feature?

2. Who? will be impacted by this feature?

3. What? particular parts of this feature do they need to create this impact?

Product Backlog

In order to buy more products As a customer I need to have a product autocompletion in the search field

3. Which features are more likely to change?

Prioritisation workshop

In order to maintain my shopping history As a site visitor I need to be able to register on this site

In order to maintain my shopping history As a site visitor I need to be able to register on this site

benefit !actor

SELECT s.* FROM backlog as s ORDER BY s.role, s.benefit LIMIT 25

4. How fully those features should be implemented?

Example workshops

Three layers of a User-Story

• Business rule(s)

• Communication

• Acceptance criteria

Three layers of a User-Story

• Business rule(s) == Acceptance criteria

• Communication

Three layers of a User-Story

• Business rule(s) == Acceptance criteria

• Communication == Examples

Three layers of a User-Story

• Business rule(s)

• Communication == Examples == Acceptance criteria

in order to maintain my shopping history as a site visitor i need to be able to register on this site

Feature: registration

in order to maintain my shopping history as a site visitor i need to be able to register on this site

Feature: registration

Scenario: Successful registration when visitor provides all the required info

in order to maintain my shopping history as a site visitor i need to be able to register on this site

Feature: registration

Scenario: Successful registration when visitor provides all the required info

Scenario: Unable to register when visitor misses required info

in order to maintain my shopping history as a site visitor i need to be able to register on this site

Feature: registration

Scenario: Successful registration when visitor provides all the required info

Scenario: Unable to register when visitor misses required info

Scenario: ...

Scenario: ...

Scenario: ...

Scenario: ...

Scenario: ...

in order to maintain my shopping history as a site visitor i need to be able to register on this site

Feature: registration

Scenario: Successful registration when visitor provides all the required info

Scenario: Unable to register when visitor misses required info

Scenario: ...

in order to maintain my shopping history as a site visitor i need to be able to register on this site

Feature: registration

Scenario: Successful registration when visitor provides all the required info

Given I am on the homepage When I follow “sign up” And I fill in registration form And I submit it Then I should be successfully registered And I should be on the homepage again

5. How to avoid gold plating?

Delivery

Architecture

ArchitectureHTTP layering

Legacy system

Infrastructure

[GET] /products

Legacy system

Infrastructure

[GET] /products

[GET] /products/123

Legacy system

Infrastructure

[GET] /products

[GET] /products/123

New system

Legacy system

Infrastructure

[GET] /products

[GET] /products/123

New system

New system

Implementation

ImplementationFull-stack BDD

Stories

Examples

Describe

ImplementDesign

Stories

Examples

Describe

ImplementDesign

Scenario-BDD

in order to maintain my shopping history as a site visitor i need to be able to register on this site

Feature: registration

Scenario: Successful registration when visitor provides all the required info

Given I am on the homepage When I follow “sign up” And I fill in registration form And I submit it Then I should be successfully registered And I should be on the homepage again

in orderas ai need

Feature:

Scenario: Successful registration when visitor provides

Given I am on the When And I fill in And I submit itThen And I should be on the homepage

What could be automated should be automated

assertEquals(Your Feature, Your App)

Setup

1. Dump your sprint features into text files

2. Put those text files into the `features/` folder inside project

3. Install behat (via composer or behat.phar)

4. Initialize behat test suite by running `bin/behat —init`

Feature Context<?php !use Behat\Behat\Context\ClosuredContextInterface, Behat\Behat\Context\TranslatedContextInterface, Behat\Behat\Context\BehatContext, Behat\Behat\Exception\PendingException; use Behat\Gherkin\Node\PyStringNode, Behat\Gherkin\Node\TableNode; !class FeatureContext extends BehatContext { }

First run$> bin/behat ... You can implement step definitions for undefined steps with these snippets: ! /** * @Then I should see :arg1 */ public function iShouldSee($arg1) { throw new PendingException(); }

...

Append snippets$> bin/behat --append-snippets

Feedback loop$> bin/behat !Feature: registration in order to maintain my shopping history as a site visitor i need to be able to register on this site ! Scenario: Successful registration when visitor provides all the required info Given I am on the homepage TODO: write pending definition When I follow “sign up” And I fill in registration form And I submit it Then I should be successfully registered And I should be on the homepage again

Stories

Examples

Describe

ImplementDesign

Scenario-BDD

Colour it Red

Colour it red /** * @Given /^I am on the homepage$/ */ public function iAmOnTheHomepage() { $crawler = new \Some\Crawler\Lib\Crawler(); $crawler->goto(“http://localhost:8080/”); if (200 !== $crawler->getCurrentStatusCode()) { throw new RuntimeException(‘Can not open homepage’); } }

Colour it red$> bin/behat !Feature: registration in order to maintain my shopping history as a site visitor i need to be able to register on this site ! Scenario: Successful registration when visitor provides all the required info Given I am on the homepage Can not open homepage (RuntimeException) When I follow “sign up” And I fill in registration form And I submit it Then I should be successfully registered And I should be on the homepage again

Stories

Examples

Describe

ImplementDesign

Scenario-BDD

Change the messageAs quickly as possible

Change the message$> bin/behat !Feature: registration in order to maintain my shopping history as a site visitor i need to be able to register on this site ! Scenario: Successful registration when visitor provides all the required info Given I am on the homepage Can not open homepage (RuntimeException) When I follow “sign up” And I fill in registration form And I submit it Then I should be successfully registered And I should be on the homepage again

Change the message$> bin/behat !Feature: registration in order to maintain my shopping history as a site visitor i need to be able to register on this site ! Scenario: Successful registration when visitor provides all the required info Given I am on the homepage Route … not found (FrameworkException) When I follow “sign up” And I fill in registration form And I submit it Then I should be successfully registered And I should be on the homepage again

Change the message$> bin/behat !Feature: registration in order to maintain my shopping history as a site visitor i need to be able to register on this site ! Scenario: Successful registration when visitor provides all the required info Given I am on the homepage Template … not found (FrameworkException) When I follow “sign up” And I fill in registration form And I submit it Then I should be successfully registered And I should be on the homepage again

Change the message$> bin/behat !Feature: registration in order to maintain my shopping history as a site visitor i need to be able to register on this site ! Scenario: Successful registration when visitor provides all the required info Given I am on the homepage When I follow “sign up” TODO: write pending definition And I fill in registration form And I submit it Then I should be successfully registered And I should be on the homepage again

behat.org

Change the message$> bin/behat !Feature: registration in order to maintain my shopping history as a site visitor i need to be able to register on this site ! Scenario: Successful registration when visitor provides all the required info Given I am on the homepage When I follow “sign up” And I fill in registration form And I submit it Then I should be successfully registered Object `User` and its method `isRegistered` does not exist (RuntimeException) And I should be on the homepage again

Stories

Examples

Describe

ImplementDesign

Spec-BDD

Setup

1. Install phpspec via composer

2. use it

Stories

Examples

Describe

ImplementDesign

Spec-BDD

Prepare your first spec$> bin/phpspec desc Acme/Userbase/User

Describe your first message<?php !namespace spec\Acme\Userbase; !class User extends ObjectBehavior{ function it_is_registered_by_default() { $this->shouldBeRegistered(); } }

Colour it red$> bin/phpspec !Class “Acme\Userbase\User” does not exist. Create? [Y/n] y !Method `Acme\Userbase\User::isRegistered()` does not exist. Create? [Y/n] y

Stories

Examples

Describe

ImplementDesign

Spec-BDD

Stories

Examples

Describe

ImplementDesign

Spec-BDD

Stories

Examples

Describe

ImplementDesign

Spec-BDD

phpspec.net

Verify feature$> bin/behat !Feature: registration in order to maintain my shopping history as a site visitor i need to be able to register on this site ! Scenario: Successful registration when visitor provides all the required info Given I am on the homepage When I follow “sign up” And I fill in registration form And I submit it Then I should be successfully registered And I should be on the homepage again

Verify feature$> bin/behat !Feature: registration in order to maintain my shopping history as a site visitor i need to be able to register on this site ! Scenario: Successful registration when visitor provides all the required info Given I am on the homepage When I follow “sign up” And I fill in registration form And I submit it Then I should be successfully registered And I should be on the homepage again

Stories

Examples

Describe

ImplementDesign

#3: Income

6 months later…

#3: Same ashtrays, better car

We do that for clients

We do that for clientsAnd teach others in those rare

moments when we don’t

http:// .com