Testing with F#

Mikael Lundin

• Publisher: Packt Publishing
• Year: 2015
• ISBN:
  9781784391232
• Topic: Ciencia de la computación
• Subtopic: Control y garantía de calidad

Testing with F#

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Table of Contents

Testing with F#

Credits

About the Author

About the Reviewers

www.PacktPub.com

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Free access for Packt account holders

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Errata

Piracy

Questions

1. The Practice of Test Automation

Testing as a practice

Black or white box testing

Manual testing

Test automation

Style check

Static analysis

Unit testing

Integration testing

System testing

Building trust

The purpose of testing

When not to test

Testing with intent

Asserting written code

Contracts versus tests

Designing code to be written

Writing tests for regression

Executable specifications

Summary

2. Writing Testable Code with Functional Programming

Purely functional

Immutability

Immutable data structures

Built-in immutable types

Tuple

List

Sequence

Creating an immutable type

Writing testable code

Active patterns

Higher order functions

Partial application

Continuations

Expressiveness through functional programming

Imperative programming

Declarative programming

Tail call optimization

Parallel execution

Summary

3. Setting Up Your Test Environment

F# Interactive

Loading external references

Testing with Visual Studio

NUnit

xUnit

Comparing MSTest, NUnit, and xUnit

Tools and frameworks

FsUnit

ReSharper test runner

xUnit.net

Executing a test suite outside Visual Studio

MSTest

NUnit

xUnit

FAKE

Continuous integration

Git Hooks

TeamCity

Summary

4. Unit Testing

Structuring your tests

Arrange, act, assert

Separate project versus inline tests

FsUnit

Assertions

Custom assertions

Unquote

Assertions

Testing in isolation

Vertical slice testing

Finding the abstraction level

Public interface

Private functions

Test doubles

Dependency injection

Functional injection

Currying

Higher order functions

Stubbing with Foq

Mocking

Dealing with databases

Summary

5. Integration Testing

Good integration tests

Layer-for-layer testing

Top down testing

External interface testing

Your first integration test

Setting up and tearing down databases

Brownfield database setup

Really large databases

Speeding up integration testing

Testing in parallel

Testing stored procedures

Data-driven testing

Testing web services

Web service type provider

Summary

6. Functional Testing

Specifications

Setting up TickSpec

Executable specifications

Combinatorial examples

Web-browser-based testing

Selenium

PhantomJS

Canopy

CSQuery

Regression testing

Summary

7. The Controversy of Test Automation

Bugs or defects

Bugs

How to avoid them

Defects

How to avoid them

The difference between bugs and defects

The cost of quality

Quality index

The software craftsman

Not all code is created equal

Being a pragmatic programmer

Good enough

Technical debt

The false security of code coverage

Measuring the delta of code coverage

Test-driven development

Red, green, refactor

Aversions to test-driven development

Test first development

Fixing bugs

API design

Testing or fact-checking

Replacing the tester with automation

Summary

8. Testing in an Agile Context

Building a bridge or tending to a garden

The broken iron triangle

Visualizing metrics

The Kanban board

Predictability

Testing

What it means to be done

Mitigating risks

Known unknowns

Unknown unknowns

Automation

Testing in agile

Summary

9. Test Smells

Tests that break upon refactoring

Tests that break occasionally

Tests that never break

Tests that are too complex

Tests that require excessive setup

Developers not writing tests

Testing is a waste

Management won't let us

We don't know where to start

Our code is hard to test

It's a thing about culture

Summary

10. The Ten Commandments of Test Automation

Testing behavior, not implementation

Using ubiquitous language in your test name

Asserting only one thing in your test

Don't mock the Mockingbird

Always refactor your SUT

Your test should never be more than 10 lines of code

Always test in isolation

Controlling your dependencies

Your test is a ninja

The test is not complex

Summary

Index

Testing with F#

Copyright © 2015 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author nor Packt Publishing and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

First published: February 2015

Production reference: 1170215

Published by Packt Publishing Ltd.

Livery Place

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Birmingham B3 2PB, UK.

ISBN 978-1-78439-123-2

www.packtpub.com

Credits

Author

Mikael Lundin

Reviewers

Neil Danson

Max Malook

Karlkim Suwanmongkol

Commissioning Editor

Amarabha Banerjee

Acquisition Editor

Reshma Raman

Content Development Editor

Shweta Pant

Technical Editor

Tanmayee Patil

Copy Editors

Gladson Monteiro

Merilyn Pereira

Nithya P

Project Coordinator

Sageer Parkar

Proofreaders

Simran Bhogal

Lauren E. Harkins

Indexer

Tejal Soni

Graphics

Sheetal Aute

Abhinash Sahu

Production Coordinator

Shantanu N. Zagade

Cover Work

Shantanu N. Zagade

About the Author

Mikael Lundin is a software developer living in Malmö, Sweden. He started programming in Pascal 20 years ago and has been enjoying the craft both professionally and as a hobby through languages and frameworks such as PHP, C#, F#, Ruby, and Node. He has been a practitioner and mentor of test-driven development and agile methodologies for the last 8 years, helping teams succeed in delivering high-quality software.

Mikael has been working with F# for 4 years, providing solutions to clients, publicly speaking about functional programming, and holding seminars for colleagues to spread the word. He strongly believes that functional programming is the future of delivering high-quality software.

Mikael is employed as a technical consultant by Valtech in Sweden, where he takes on the roles of a software developer, solution architect, and agile mentor. He has delivered quality software to high-profile international clients and helped organizations adopt Scrum as their software development practice.

I would like to thank my employer, Valtech, for always letting me experiment with new technologies and giving me the encouragement to learn and share my knowledge. I also would like to thank my wife, Jenny, for understanding my need to undertake a project that infringed on our time and time with our family. Finally, I would like to thank my colleagues for always being supportive of the challenging tasks I set out to do.

About the Reviewers

Neil Danson is an active professional developer and passionate F# advocate since 2010. He has over 10 years of experience in using the .NET framework, working on varied projects that range from military software and huge-scale international news websites to high-performance trading platforms. When Neil is not working, he can usually be found writing games, compilers, raytracers, and anything else that pops into his head. He can be found occasionally blogging at https://neildanson.wordpress.com.

I would like to thank my wife, Carla, for puttin...