structs3.rs (2592B)
1 // Structs contain data, but can also have logic. In this exercise, we have 2 // defined the `Package` struct, and we want to test some logic attached to it. 3 4 #[derive(Debug)] 5 struct Package { 6 sender_country: String, 7 recipient_country: String, 8 weight_in_grams: u32, 9 } 10 11 impl Package { 12 fn new(sender_country: String, recipient_country: String, weight_in_grams: u32) -> Self { 13 if weight_in_grams < 10 { 14 // This isn't how you should handle errors in Rust, but we will 15 // learn about error handling later. 16 panic!("Can't ship a package with weight below 10 grams"); 17 } 18 19 Self { 20 sender_country, 21 recipient_country, 22 weight_in_grams, 23 } 24 } 25 26 // TODO: Add the correct return type to the function signature. 27 fn is_international(&self) -> bool { 28 // TODO: Read the tests that use this method to find out when a package 29 // is considered international. 30 self.sender_country != self.recipient_country 31 } 32 33 // TODO: Add the correct return type to the function signature. 34 fn get_fees(&self, cents_per_gram: u32) -> u32 { 35 // TODO: Calculate the package's fees. 36 self.weight_in_grams * cents_per_gram 37 } 38 } 39 40 fn main() { 41 // You can optionally experiment here. 42 } 43 44 #[cfg(test)] 45 mod tests { 46 use super::*; 47 48 #[test] 49 #[should_panic] 50 fn fail_creating_weightless_package() { 51 let sender_country = String::from("Spain"); 52 let recipient_country = String::from("Austria"); 53 54 Package::new(sender_country, recipient_country, 5); 55 } 56 57 #[test] 58 fn create_international_package() { 59 let sender_country = String::from("Spain"); 60 let recipient_country = String::from("Russia"); 61 62 let package = Package::new(sender_country, recipient_country, 1200); 63 64 assert!(package.is_international()); 65 } 66 67 #[test] 68 fn create_local_package() { 69 let sender_country = String::from("Canada"); 70 let recipient_country = sender_country.clone(); 71 72 let package = Package::new(sender_country, recipient_country, 1200); 73 74 assert!(!package.is_international()); 75 } 76 77 #[test] 78 fn calculate_transport_fees() { 79 let sender_country = String::from("Spain"); 80 let recipient_country = String::from("Spain"); 81 82 let cents_per_gram = 3; 83 84 let package = Package::new(sender_country, recipient_country, 1500); 85 86 assert_eq!(package.get_fees(cents_per_gram), 4500); 87 assert_eq!(package.get_fees(cents_per_gram * 2), 9000); 88 } 89 }