Book Image

Hands-On Functional Programming in RUST

By : Andrew Johnson
Book Image

Hands-On Functional Programming in RUST

By: Andrew Johnson

Overview of this book

Functional programming allows developers to divide programs into smaller, reusable components that ease the creation, testing, and maintenance of software as a whole. Combined with the power of Rust, you can develop robust and scalable applications that fulfill modern day software requirements. This book will help you discover all the Rust features that can be used to build software in a functional way. We begin with a brief comparison of the functional and object-oriented approach to different problems and patterns. We then quickly look at the patterns of control flow, data the abstractions of these unique to functional programming. The next part covers how to create functional apps in Rust; mutability and ownership, which are exclusive to Rust, are also discussed. Pure functions are examined next and you'll master closures, their various types, and currying. We also look at implementing concurrency through functional design principles and metaprogramming using macros. Finally, we look at best practices for debugging and optimization. By the end of the book, you will be familiar with the functional approach of programming and will be able to use these techniques on a daily basis.
Table of Contents (12 chapters)

Writing tests

To run tests from the command line, type cargo test. We will be doing this a lot.

Unit testing

Unit testing focuses on testing internal interfaces and components of a program. It is also called whitebox testing. To first create unit tests, it is a good idea to look at all of the top-level types, traits, and functions. All top-level identifiers make for good test cases. Depending on the structure of the program, it may also be a good idea to test combinations of these components to cover expected use cases.

We have one utility function, the statistic calculation, which would be a good candidate to write a unit test for. However, this function doesn't return any result. Instead, it immediately prints output...