sassman

#!/usr/bin/env python

import sys, yaml, json

try:
    # included in standard lib from Python 2.7
    from collections import OrderedDict
except ImportError:
    # try importing the backported drop-in replacement
    # it's available on PyPI

sassman

// test/alphabet_position_spec.rs
use dev_challenge_47::alphabet_position;
use speculate::speculate;

speculate! {                  // <-- it's a macro but who cares
    describe "alphabet_position" {
        it "should replace 'a' with 1" {
            assert_eq!(alphabet_position("a"), "1");
        }
        it "should replace 'A' with 1" {

sassman

// test/alphabet_position_test.rs

#[test]
fn it_should_replace_the_sentence() {
    let replaced = alphabet_position("The sunset sets at twelve o' clock.");
    assert_eq!(
        replaced,
        "20 8 5 19 21 14 19 5 20 19 5 20 19 1 20 20 23 5 12 22 5 15 3 12 15 3 11"
    );
}

sassman

// src/lib.rs

pub fn alphabet_position(s: &str) -> String {
    s.to_lowercase()
        .chars()
        .filter(|x| x.is_alphabetic())        // <-- adding this line here
        .map(|x| -> u8 { x as u8 - 'a' as u8 + 1 })
        .map(|x| -> String { x.to_string() })
        .collect::<Vec<String>>()
        .join(" ")

sassman

// test/alphabet_position_test.rs

#[test]
fn it_should_ignore_non_characters() {
    let replaced = alphabet_position("'a a. 2");
    assert_eq!(replaced, "1 1");
}

sassman

// src/lib.rs

pub fn alphabet_position(s: &str) -> String {
    s.to_lowercase()      // <-- adding this line
        .chars()
        .map(|x| -> u8 { x as u8 - 'a' as u8 + 1 })
        .map(|x| -> String { x.to_string() })
        .collect::<Vec<String>>()
        .join(" ")
}

sassman

// test/alphabet_position_test.rs

#[test]
fn it_should_replace_the_capital_a_with_1() {
    let replaced = alphabet_position("A");
    assert_eq!(replaced, "1");
}

sassman

// src/lib.rs

pub fn alphabet_position(s: &str) -> String {
    s.chars()                             // <-- get an iterator over all chars
        .map(|x| -> u8 { x as u8 - 'a' as u8 + 1 })   // <-- substract the ascii value of 'a'
        .map(|x| -> String { x.to_string() })         // <-- convert the char to a String
        .collect::<Vec<String>>()                     // <-- collect a Vector of String
        .join(" ")                                    // <-- join the Strings by whitespace
}

sassman

// src/lib.rs

pub fn alphabet_position(s: &str) -> String {
    String::from("Hello")
}

sassman

// test/alphabet_position_test.rs

use dev_challenge_47::alphabet_position;    // <-- we don't have this function yet

#[test]                                     // <-- how to define a test in rust
fn it_should_replace_the_a_with_1() {       // <-- we express the requirement as name
    let replaced = alphabet_position("a");
    assert_eq!(replaced, "1");              // <-- we assert that the both are equal
}