Table of Contents

Copyright

Brief Table of Contents

Table of Contents

Preface

Acknowledgments

About this book

About the Author

About the cover illustration

1. Why it all matters

Chapter 1. The bigger picture

1.1. Python is an enterprise language

1.1.1. The times they are a-changin’

1.1.2. What I like about Python

1.2. Python is a teaching language

1.3. Design is a process

1.3.1. The user experience

1.3.2. You’ve been here before

1.4. Design enables better software

1.4.1. Considerations in software design

1.4.2. Organically grown software

1.5. When to invest in design

1.6. New beginnings

1.7. Design is democratic

1.7.1. Presence of mind

1.8. How to use this book

Summary

2. Foundations of design

Chapter 2. Separation of concerns

2.1. Namespacing

2.1.1. Namespaces and the import statement

2.1.2. The many masks of importing

2.1.3. Namespaces prevent collisions

2.2. The hierarchy of separation in Python

2.2.1. Functions

2.2.2. Classes

2.2.3. Modules

2.2.4. Packages

Summary

Chapter 3. Abstraction and encapsulation

3.1. What is abstraction?

3.1.1. The “black box”

3.1.2. Abstraction is like an onion

3.1.3. Abstraction is a simplifier

3.1.4. Decomposition enables abstraction

3.2. Encapsulation

3.2.1. Encapsulation constructs in Python

3.2.2. Expectations of privacy in Python

3.3. Try it out

3.3.1. Refactoring

3.4. Programming styles are an abstraction too

3.4.1. Procedural programming

3.4.2. Functional programming

3.4.3. Declarative programming

3.5. Typing, inheritance, and polymorphism

3.6. Recognizing the wrong abstraction

3.6.1. Square pegs in round holes

3.6.2. Clever gets the cleaver

Summary

Chapter 4. Designing for high performance

4.1. Hurtling through time and space

4.1.1. Complexity is a little . . . complex

4.1.2. Time complexity

4.1.3. Space complexity

4.2. Performance and data types

4.2.1. Data types for constant time

4.2.2. Data types for linear time

4.2.3. Space complexity of operations on data types

4.3. Make it work, make it right, make it fast

4.3.1. Making it work

4.3.2. Making it right

4.3.3. Making it fast

4.4. Tools

4.4.1. timeit

4.4.2. CPU profiling

4.5. Try it out

Summary

Chapter 5. Testing your software

5.1. What is software testing?

5.1.1. Does it do what it says on the tin?

5.1.2. The anatomy of a functional test

5.2. Functional testing approaches

5.2.1. Manual testing

5.2.2. Automated testing

5.2.3. Acceptance testing

5.2.4. Unit testing

5.2.5. Integration testing

5.2.6. The testing pyramid

5.2.7. Regression testing

5.3. Statements of fact

5.4. Unit testing with unittest

5.4.1. Test organization with unittest

5.4.2. Running tests with unittest

5.4.3. Writing your first test with unittest

5.4.4. Writing your first integration test with unittest

5.4.5. Test doubles

5.4.6. Try it out

5.4.7. Writing interesting tests

5.5. Testing with pytest

5.5.1. Test organization with pytest

5.5.2. Converting unittest tests to pytest

5.6. Beyond functional testing

5.6.1. Performance testing

5.6.2. Load testing

5.7. Test-driven development: A primer

5.7.1. It’s a mindset

5.7.2. It’s a philosophy

Summary

3. Nailing down large systems

Chapter 6. Separation of concerns in practice

6.1. A command-line bookmarking application

6.2. A tour of Bark

6.2.1. The benefits of separation: Reprise

6.3. An initial code structure, by concern

6.3.1. The persistence layer

6.3.2. The business logic layer

6.3.3. The presentation layer

Summary

Chapter 7. Extensibility and flexibility

7.1. What is extensible code?

7.1.1. Adding new behaviors

7.1.2. Modifying existing behaviors

7.1.3. Loose coupling

7.2. Solutions for rigidity

7.2.1. Letting go: Inversion of control

7.2.2. The devil’s in the details: Relying on interfaces

7.2.3. Fighting entropy: The robustness principle

7.3. An exercise in extension

Summary

Chapter 8. The rules (and exceptions) of inheritance

8.1. The inheritance of programming past

8.1.1. The silver bullet

8.1.2. The challenges of hierarchies

8.2. The inheritance of programming present

8.2.1. What is inheritance for, really?

8.2.2. Substitutability

8.2.3. The ideal use case for inheritance

8.3. Inheritance in Python

8.3.1. Type inspection

8.3.2. Superclass access

8.3.3. Multiple inheritance and method resolution order

8.3.4. Abstract base classes

8.4. Inheritance and composition in Bark

8.4.1. Refactoring to use an abstract base class

8.4.2. A final check on your inheritance work

Summary

Chapter 9. Keeping things lightweight

9.1. How big should my class/function/module be?

9.1.1. Physical size

9.1.2. Single responsibility

9.1.3. Code complexity

9.2. Breaking down complexity

9.2.1. Extracting configuration

9.2.2. Extracting functions

9.3. Decomposing classes

9.3.1. Initialization complexity

9.3.2. Extracting classes and forwarding calls

Summary

Chapter 10. Achieving loose coupling

10.1. Defining coupling

10.1.1. The connective tissue

10.1.2. Tight coupling

10.1.3. Loose coupling

10.2. Recognizing coupling

10.2.1. Feature envy

10.2.2. Shotgun surgery

10.2.3. Leaky abstractions

10.3. Coupling in Bark

10.4. Addressing coupling

10.4.1. User messaging

10.4.2. Bookmark persistence

10.4.3. Try it out

Summary

4. What’s next?

Chapter 11. Onward and upward

11.1. What now?

11.1.1. Develop a plan

11.1.2. Execute the plan

11.1.3. Track your progress

11.2. Design patterns

11.2.1. Ups and downs of design patterns in Python

11.2.2. Terms to start with

11.3. Distributed systems

11.3.1. Modes of failure in distributed systems

11.3.2. Addressing application state

11.3.3. Terms to start with

11.4. Take a Python deep dive

11.4.1. Python code style

11.4.2. Language features are patterns

11.4.3. Terms to start with

11.5. Where you’ve been

11.5.1. There and back again: A developer’s tale

11.5.2. Signing off

Summary

Appendix Installing Python

A.1 What version of Python should I use?

A.2 The “system” Python

A.3 Installing other versions of Python

A.3.1 Download the official Python

A.3.2 Download using Anaconda

A.4 Verifying the installation

  

  

Index

List of Figures

List of Listings