rustlings/exercises/hashmaps/hashmaps2.rs

// hashmaps2.rs
// We're collecting different fruits to bake a delicious fruit cake.
// For this, we have a basket, which we'll represent in the form of a hash
// map. The key represents the name of each fruit we collect and the value
// represents how many of that particular fruit we have collected.
// Three types of fruits - Apple (4), Mango (2) and Lychee (5) are already
// in the basket hash map.
// You must add fruit to the basket so that there is at least
// one of each kind and more than 11 in total - we have a lot of mouths to feed.
// You are not allowed to insert any more of these fruits!
//
// Make me pass the tests!
//
// Execute `rustlings hint hashmaps2` or use the `hint` watch subcommand for a hint.

// I AM NOT DONE

use std::collections::HashMap;

#[derive(Hash, PartialEq, Eq)]
enum Fruit {
    Apple,
    Banana,
    Mango,
    Lychee,
    Pineapple,
}

fn fruit_basket(basket: &mut HashMap<Fruit, u32>) {
    let fruit_kinds = vec![
        Fruit::Apple,
        Fruit::Banana,
        Fruit::Mango,
        Fruit::Lychee,
        Fruit::Pineapple,
    ];

    for fruit in fruit_kinds {
        // TODO: Insert new fruits if they are not already present in the basket.
        // Note that you are not allowed to put any type of fruit that's already
        // present!
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    // Don't modify this function!
    fn get_fruit_basket() -> HashMap<Fruit, u32> {
        let mut basket = HashMap::<Fruit, u32>::new();
        basket.insert(Fruit::Apple, 4);
        basket.insert(Fruit::Mango, 2);
        basket.insert(Fruit::Lychee, 5);

        basket
    }

    #[test]
    fn test_given_fruits_are_not_modified() {
        let mut basket = get_fruit_basket();
        fruit_basket(&mut basket);
        assert_eq!(*basket.get(&Fruit::Apple).unwrap(), 4);
        assert_eq!(*basket.get(&Fruit::Mango).unwrap(), 2);
        assert_eq!(*basket.get(&Fruit::Lychee).unwrap(), 5);
    }

    #[test]
    fn at_least_five_types_of_fruits() {
        let mut basket = get_fruit_basket();
        fruit_basket(&mut basket);
        let count_fruit_kinds = basket.len();
        assert!(count_fruit_kinds >= 5);
    }

    #[test]
    fn greater_than_eleven_fruits() {
        let mut basket = get_fruit_basket();
        fruit_basket(&mut basket);
        let count = basket.values().sum::<u32>();
        assert!(count > 11);
    }
}