Book Image

Agile Technical Practices Distilled

By : Pedro M. Santos, Marco Consolaro, Alessandro Di Gioia
Book Image

Agile Technical Practices Distilled

By: Pedro M. Santos, Marco Consolaro, Alessandro Di Gioia

Overview of this book

The number of popular technical practices has grown exponentially in the last few years. Learning the common fundamental software development practices can help you become a better programmer. This book uses the term Agile as a wide umbrella and covers Agile principles and practices, as well as most methodologies associated with it. You’ll begin by discovering how driver-navigator, chess clock, and other techniques used in the pair programming approach introduce discipline while writing code. You’ll then learn to safely change the design of your code using refactoring. While learning these techniques, you’ll also explore various best practices to write efficient tests. The concluding chapters of the book delve deep into the SOLID principles - the five design principles that you can use to make your software more understandable, flexible and maintainable. By the end of the book, you will have discovered new ideas for improving your software design skills, the relationship within your team, and the way your business works.
Table of Contents (31 chapters)
Free Chapter
Section 1
Section 2
Section 3
Section 4
Chapter 21
License: CyberDojo

The Direction of Dependencies

Dependencies have a direction. So, what is the correct direction? Let's consider this with the following diagram:

Figure 16.5: The direction of dependencies

The dependencies should follow a direction of movement from what is more likely to change, toward what is less likely to change; hence, abstraction should not depend on details. The domain should be the pure part of our code, ideally with no dependencies to anything else, since it's the least likely to change.

If you think about it, this makes sense; the business logic should be self-containing and should work correctly without caring if the information is saved on this or that database, displayed on the web, or in a CSV file. Changing a webpage to display information in an alternative way should be possible without changing the domain, and it happens way more often than modifications of the domain itself.

Outside-In naturally follows the same direction of dependencies...