Better and Faster: A Journey Toward Clean Code and Enjoyment

A Journey Toward Clean
Code and Enjoyment
Impact and Logistics of
Software Craftsmanship on
True Business Agility

A Journey Toward Clean
Code and Enjoyment
Impact and Logistics of
Software Craftsmanship on
True Business Agility
https://www.linkedin.com/in/chrisholland
https://github.com/elchris
@chrisholland

What makes Software Not Fun?
Where does it hurt us?
Can we make it Fun?

Web App. Architectures
TDD: Better Fuels Faster

Empowering OOP

Better Code: Enablers
Empowering OOP

Bad Code vs Agility
Empowering OOP

Bad Code
(what could possibly go wrong?)

Taking Away Our Fun
❖ Inheriting Someone else’s code
❖ Having a hard time understanding how a system works
❖ Breaking old things when building new things
❖ Testing our work as much as we ought to

A Word about “Agility" …
We need to be more …

We need to be more …
Agile!

Re-inventing Project
Management
&
Task-Planning

Management
&
Task-Planning
Scrum / Kanban

Management
&
Task-Planning
Scrum / Kanban
Scripting Integration
“Integration Hell”

Management
&
Task-Planning
Scrum / Kanban
CI / CD

Management
&
Task-Planning
Scrum / Kanban
CI / CD
Build MVC
Applications
Faster

Management
&
Task-Planning
Scrum / Kanban
CI / CD
Build MVC
Applications
Faster
MVC Frameworks

Underlying Issue:
…
Management
&
Task-Planning
Scrum / Kanban
CI / CD
Build MVC
Applications
Faster
MVC Frameworks

Management
&
Task-Planning
Scrum / Kanban
CI / CD
Build MVC
Applications
Faster
MVC Frameworks
Underlying Issue:
…

Management
&
Task-Planning
Scrum / Kanban
CI / CD
Build MVC
Applications
Faster
MVC Frameworks
Underlying Issue:
…
Bad Software !

A Word about “Agility” …
❖ https://martinfowler.com/bliki/FlaccidScrum.html

- We are Agile !

- We are Agile !
- You’re Not !

A Word about “Agility” …
❖ Bad Software eviscerates just about every beneﬁt of
your “Agile Stack”.

Short-Lived Agility
New Features Released
Time
Technical Debt
(Bad Code)

Time
Short-Lived Agility
Technical Debt
(Bad Code)

Time
Short-Lived Agility
Technical Debt
(Bad Code)
Not
Agile

Short-Lived Agility
Business Value
Time

Short-Lived Agility
Business Value
Time
Bad Software starts
weighing you down

Short-Lived Agility
Business Value
Time
Fail to Pivot

Short-Lived Agility
Business Value
Time
Competition Takes Over

Your Competition has a Straw …
Competition

Your Competition has a Straw …
Competition
You

Bad Code vs Agility
http://bit.ly/future-programming

TDD
Patterns
Clean Code

TDD
Patterns
Clean Code
Better Software

Better Code: TDD
❖ (We’ll come back to that)

Better Code: Clean
Code
http://bit.ly/
clean-code-book

Better Code: Patterns
❖ Most Languages Support Paradigms to varying degrees.
❖ Object-Oriented
❖ Procedural, Imperative
❖ Functional

❖ These paradigms are only as effective as our ability to
seek out and leverage … Patterns.

❖ Proper leverage of Patterns helps simplify complexity.

Programming Paradigms
Procedural, Imperative
Object-Oriented
Functional
Patterns
SOLID Principles
GoF Design Patterns
Enterprise
Application - Martin
Fowler

❖ OOP Patterns:
❖ designpatternsphp.readthedocs.io
❖ Functional Patterns:
❖ https://fsharpforfunandproﬁt.com/fppatterns/(Scott
Wlaschin)
❖ Streams in Java 8
❖ ƒP Use-Cases ( Uncle Bob )
❖ Intro to ƒP ( Anjana Vakil )

Web Apps: OOP Patterns
P1: Factory, Command, Repository, Data Mapper
P2: Strategy, Decorator, Adapter / Wrapper
P3: Builder
P0: Dependency Injection

Large System
Component
Component
Component

Large System
Component
Component
Component
Component
Component
Component

Large System
Component
Component
Component
Component
Component
Component Tight
Couplings

Large System
Component
Component
Component
Component
Component
Component
Component
Component
Component
Tight
Couplings

Large System
Component
Component
Component
Component
Component
Component
Component
Component
Component
Tight
Couplings
Change One Thing,
Break Everything

Flaccid OOP
❖ Indiscriminate use of OOP Constructs
❖ Random instantiation of Classes
❖ Unpredictable System Coupling
❖ Unpredictable System State
❖ Law of Demeter Violations (Past Meetup)

OOP Goals
❖ Simple, Maintainable System
❖ Loosely-Coupled Components
❖ Consistent Dependency Graph
❖ Embracing Design Patterns

Large System
Component Component Component

Large System
Loose
Couplings

Large System
Loose
Couplings
Change One Thing,
Break Nothing

Large System
Loose
Couplings
Change One Thing,
Break Nothing
Design Patterns FTW !

MVC Sweet Spot
❖ Skinning your Database
❖ Each URI performs one CRUD Operation against
database.

MVC Limitations
❖ Most applications start out simple …
❖ … then get more complex
❖ … no real layer for Business Logic

Framework Coupling
Framework
Middleware
Framework
Persistence
Business

Framework De-Coupling
Business
Framework
Middleware
Framework
Persistence

Beyond MVC: CSRVCED
Acceptance & Integration Tests
http://codeception.com
http://www.seleniumhq.org
è Tests should be lightweight
100% Unit-Test Coverage
Commands
Services
Repositories
Controllers
Entities
DTOs
Views
Interfaces
Interfaces

Beyond MVC: CSRVCED
Commands
Services
Repositories
Controllers
Entities
DTOs
Views
Interfaces
Interfaces
ORM ODM SQL NoSQL
Polyglot Persistence

Beyond MVC: CSRVCED
❖ Yellow Zone: “Irrelevant”
❖ Very thin: 1% of code-base. If that.
❖ Coupled to Transport: HTTP / HTML
❖ Coupled to Framework

Beyond MVC: CSRVCED
❖ Green Zone: “What Matters”
❖ 99%+ of code-base
❖ Transport-Agnostic
❖ Framework-Agnostic

Web App: Repositories
❖ Can be backed by any data store
❖ Swappable implementation as needs evolve:
❖ RDBMS -> NoSQL: Data Storage Scalability
❖ ORM -> Raw SQL: Increase Performance

❖ Watch: http://bit.ly/clean-architecture-video
❖ Read: http://bit.ly/clean-architecture

Why TDD?
❖ Speed (more on that later)

Why TDD?
❖ Embrace Change

Why TDD?
❖ Embrace Change
❖ Requirements
❖ New Features

Why TDD?
❖ Embrace Change
❖ Requirements
❖ New Features
❖ Constantly Improve Code

Improving Code
TDD
Patterns
Clean Code
Better Software

TDD vs Unit Tests
❖ After the Fact Testing: “Now I have to cover my code”
❖ Test-Driven Development: “I code to my assertions”

TDD: Web Applications Challenges
❖ Most TDD Tutorials focus on simple algorithmic
problems.
❖ And yet, Web Apps:
❖ Have several Architectural Layers
❖ (Should) Have many Classes
❖ Are heavily Data/IO Driven

Web Apps TDD: Goals
❖ Get Satisfaction of Building Business Capabilities
❖ … Without leaving comfort of Test Harness

Without TDD:
Where do we waste Time?

Wasting Time without TDD
❖ While Building Things
❖ While Testing Things

Web Apps: Time Wasted
❖ While Building Things:
❖ Set-up local DB
❖ Scaffold / bootstrap basic UI
❖ Write Code
❖ Use debugger to step thru code
❖ Use logging to trace behavior & debug issues

Web Apps: Time Wasted
❖ While Testing Things:
❖ Click UI to get application into given state
❖ Visually inspect database records to verify behavior
❖ Manually modify DB records to jump to state
❖ Break things as you build new things

Web Apps: Old Workflow
❖ All Activities marked in RED are throw-away activities.
❖ They are manual and repetitive
❖ … relevant only once

Web Apps: Desired Workflow
❖ Coding Against Assertions:
❖ Write Failing Test
❖ Write Code to make the Test Pass
❖ Refactor

Web Apps: Desired Workflow
❖ All Activities marked in GREEN are foundational
activities.
❖ Permanently relevant

Web Apps TDD
❖ Work effectively across architectural boundaries
❖ Introduce meaningful Data into Tests …
❖ … While making meaningful assertions

xUnit: Test Harness
ORM
in-memory
DB

xUnit: Test Harness
ORM
in-memory
DB
Unit Test

xUnit: Test Harness
ORM
in-memory
DB
Unit Test
Unit Test

xUnit: Test Harness
ORM
in-memory
DB
Unit Test
Unit Test
Unit Test

Web Apps TDD: Tooling
❖ xUnit
❖ ORM w/ Code-First Data Mapper Pattern
❖ In-Memory DB
❖ …

Web Apps TDD: PHP
❖ xUnit
❖ PHPUnit
❖ Doctrine ORM
❖ In-Memory DB
❖ SQLite

Web Apps TDD: Java
❖ xUnit
❖ jUnit
❖ Hibernate
❖ In-Memory DB
❖ HSQLDB

Web Apps TDD: .Net/C#
❖ xUnit
❖ NUnit
❖ Entity Framework or NHibernate
❖ In-Memory DB
❖ SQL CE

Web Apps TDD: Covenants
❖ Commit to TDD and enforce with:
❖ Tooling to ensure 100% coverage, at all times
❖ Peer code reviews to verify that all tests have
meaningful assertions

Web Apps TDD: Covenants
❖ You don’t want:
❖ Less than 100% coverage. TDD gives you that for free.
Going below 100% means someone isn’t doing TDD.
❖ Code that is 100% covered with meaningless
assertions. This also means someone isn’t doing TDD.

Decouple
Business Logic
from
Framework Stack

TDDing a Web App
Commands
Services
Repositories
Controllers
Entities
DTOs
Views
Interfaces
Interfaces

Business Logic
Coupled Workflow

Controller
Business Logic
Coupled Workflow

Route
Controller
Business Logic
Coupled Workflow

UI
Route
Controller
Business Logic
Coupled Workflow

UI
Route
Controller
Business Logic
Migrations
Coupled Workflow

UI
Route
Controller
Business Logic
Schema
Migrations
Coupled Workflow

UI
Route
Controller
Business Logic
Schema
Migrations
Coupled Workflow
Intertwined
Concerns

UI
Route
Controller
Business Logic
Schema
Migrations
Coupled Workflow
Intertwined
Concerns
Less Productive TDD

UI
Route
Controller
Business Logic
Schema
Migrations
De-Coupled Workflow

Business Logic
De-Coupled Workflow
Repos ServicesEntities
UI
Route
ControllerSchema
Migrations

Business Logic
De-Coupled Workflow
TDD
UI
Route
ControllerSchema
Migrations

Business Logic
De-Coupled Workflow
TDD
UI
Route
ControllerSchema
Migrations
TDD in
Rapid Iterations

Business Logic
De-Coupled Workflow
TDD
UI
Route
ControllerSchema
Migrations
ORM
TDD in
Rapid Iterations

Business Logic
De-Coupled Workflow
TDD
UI
Route
ControllerSchema
Migrations
ORM
Auto-Generated
Migrations
from
Entity Graph
TDD in
Rapid Iterations

Business Logic
De-Coupled Workflow
TDD
UI
Route
ControllerSchema
Migrations
ORM
Manual
Testing
Auto-Generated
Migrations
from
Entity Graph
TDD in
Rapid Iterations

TDD Service
TDD
Repo(s)
TDD Service
TDD
Repo(s)

TDD Service
TDD
Repo(s)
TDD Service
TDD
Repo(s)
Build UI
Concurrently

TDD Service
TDD
Repo(s)
TDD Service
TDD
Repo(s)
TDD Service
TDD
Repo(s)
Build UI
Concurrently

Map URI Routes to Service Methods
Build UI
Concurrently
TDD Service
TDD
Repo(s)
TDD Service
TDD
Repo(s)
TDD Service
TDD
Repo(s)

Generate SQL Migration from Entity Graph
Build UI
Concurrently
TDD Service
TDD
Repo(s)
TDD Service
TDD
Repo(s)
TDD Service
TDD
Repo(s)

Run SQL Migrations against Local RDBMS
Build UI
Concurrently
TDD Service
TDD
Repo(s)
TDD Service
TDD
Repo(s)
TDD Service
TDD
Repo(s)

Build UI
Concurrently
Test Application thru the UI
TDD Service
TDD
Repo(s)
TDD Service
TDD
Repo(s)
TDD Service
TDD
Repo(s)

TDD Service
TDD
Repo
TDD Service
TDD
Repo
TDD Service
TDD
Repo
Build UI
Concurrently
Zone 1
Zone 2

TDD Service
TDD
Repo
TDD Service
TDD
Repo
TDD Service
TDD
Repo
Zone 1
Build UI
Concurrently
Zone 2

TDD Service
TDD
Repo
TDD Service
TDD
Repo
TDD Service
TDD
Repo
Zone 1
Build UI
Concurrently
Zone 2
Decoupled

TDD Workflow Advantages
❖ Implement Most Business Logic in Zone 1
❖ Without having to depend on Zone 2
❖ Rapid, Localized TDD iterations in Zone 1

Next Steps
❖ Generate Migration SQL File with “doctrine diff”
❖ Map Controller / Routes to Service Methods
❖ Deploy Code
❖ Run SQL Migrations

Web Apps TDD: Code
❖ http://bit.ly/tdd-kata-php-video <— Watch Video
❖ See demo-run-4 branch <— Source Code Link

TDD: More Reading
❖ TDD Harms App Architecture (Uncle Bob)
❖ Giving-Up on TDD (Uncle Bob)
❖ http://xunitpatterns.com ( Gerard Meszaros )

More Reading
❖ http://bit.ly/refactoring-book ( Martin Fowler )
❖ http://bit.ly/legacy-code-book ( Michael Feathers )

Web Apps TDD: Benefits
❖ Keep UI Workﬂows Decoupled …
❖ … from solving Business Problems

❖ Get in the Zone, Stay in it.

❖ Easy to get back into the Zone after interruption
❖ Last Test you wrote is your “anchor”

❖ No need to worry about “Optimal Design”
❖ Code can always be improved.
❖ Because covered.

❖ No need to worry about “Optimal Design”
❖ Code can always be improved.
❖ Because covered.
Implement First, Optimize Later

❖ 100% code coverage “For Free”
❖ Sustained Velocity => Agility
❖ Unit Tests are the Living Documentation of our App

When to do TDD
❖ When Prototyping!
❖ … Ship faster with TDD
❖ … Embrace constant change
❖ Ship constantly

When to do TDD
❖ When Building Complex Things
❖ When Building Simpler Things

Better Software
Means more Fun

Better Software
Keeps you in Business

TDD
Patterns
Clean Code
Better Software

Great Software & Agile Stack
Management
&
Task-Planning
Scrum / Kanban
CI / CD
Build MVC
Applications
Faster
MVC Frameworks
Better
Software

Sustained Agility
Time
Business Value

Questions?
https://github.com/elchris @chrisholland

Questions?
I’m Hiring !

Questions?
I’m Hiring !
http://bit.ly/software-craftsman-wanted

Better and Faster: A Journey Toward Clean Code and Enjoyment

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Better and Faster: A Journey Toward Clean Code and Enjoyment