Den Dribbles

Rust Fizzbuzz

April 13, 2019

A basic implementation of FizzBuzz in Rust.

Writing the Code

Execute the tests with:

$ cargo test

All but the first test have been ignored. After you get the first test to pass, open the tests source file which is located in the tests directory and remove the #[ignore] flag from the next test and get the tests to pass again. Each separate test is a function with #[test] flag above it. Continue, until you pass every test.

If you wish to run all tests without editing the tests source file, use:

$ cargo test -- --ignored

To run a specific test, for example some_test, you can use:

$ cargo test some_test

If the specific test is ignored use:

$ cargo test some_test -- --ignored

To learn more about Rust tests refer to the [online test documentation][rust-tests]

Make sure to read the Modules chapter if you haven’t already, it will help you with organizing your files.

Further improvements

After you have solved the exercise, please consider using the additional utilities, described in the installation guide, to further refine your final solution.

To format your solution, inside the solution directory use

cargo fmt

Cargo.toml

Setup your Cargo.toml file to look like the following:

[package]
edition = "2019"
name = "fizz_buzz"
version = "0.1.0"

[[test]]
name = "fizz_buzz"
path = "tests/fizz_buzz.rs"

[dependencies]
# itoa = "0.4.3"

The test file

In tests/fizz_buzz.rs:

extern crate fizz_buzz;


#[test]
fn test_returns_string() {
    assert_eq!("2", fizz_buzz::run(2));
}

#[test]
fn test_fizz() {
    assert_eq!("Fizz", fizz_buzz::run(3));
}

#[test]
fn test_buzz() {
    assert_eq!("Buzz", fizz_buzz::run(5));
}

#[test]
fn test_fizz_buzz() {
    assert_eq!("FizzBuzz", fizz_buzz::run(15));
}

FizzBuzz

Create src/libs.rs:

pub fn run(i: u32) -> String {
    if i % 15 == 0 {
        "FizzBuzz".to_string()
    } else if i % 5 == 0 {
        "Buzz".to_string()
    } else if i % 3 == 0 {
        "Fizz".to_string()
    } else {
        i.to_string()
    }
}

Run the final test

cargo test


A personal blog on all things of interest. Written by Dennis O'Keeffe, Follow me on Twitter