structs3 solution

exercises/07_structs/structs3.rs

@@ -1,6 +1,5 @@
 // Structs contain data, but can also have logic. In this exercise we have
-// defined the Package struct and we want to test some logic attached to it.
-// Make the code compile and the tests pass!
+// defined the `Package` struct and we want to test some logic attached to it.
 
 #[derive(Debug)]
 struct Package {
@@ -10,26 +9,28 @@ struct Package {
 }
 
 impl Package {
-    fn new(sender_country: String, recipient_country: String, weight_in_grams: u32) -> Package {
+    fn new(sender_country: String, recipient_country: String, weight_in_grams: u32) -> Self {
         if weight_in_grams < 10 {
-            // This is not how you should handle errors in Rust,
-            // but we will learn about error handling later.
-            panic!("Can not ship a package with weight below 10 grams.")
-        } else {
-            Package {
-                sender_country,
-                recipient_country,
-                weight_in_grams,
-            }
+            // This isn't how you should handle errors in Rust, but we will
+            // learn about error handling later.
+            panic!("Can't ship a package with weight below 10 grams");
+        }
+
+        Self {
+            sender_country,
+            recipient_country,
+            weight_in_grams,
         }
     }
 
-    fn is_international(&self) -> ??? {
-        // Something goes here...
+    // TODO: Add the correct return type to the function signature.
+    fn is_international(&self) {
+        // TODO: Read the tests that use this method to find out when a package is concidered international.
     }
 
-    fn get_fees(&self, cents_per_gram: u32) -> ??? {
-        // Something goes here...
+    // TODO: Add the correct return type to the function signature.
+    fn get_fees(&self, cents_per_gram: u32) {
+        // TODO: Calculate the package's fees.
     }
 }
 

rustlings-macros/info.toml

@@ -434,7 +434,7 @@ the places it goes through right?
 For `get_fees`: This method takes an additional argument, is there a field in
 the `Package` struct that this relates to?
 
-Have a look in The Book, to find out more about method implementations:
+Have a look in The Book to find out more about method implementations:
 https://doc.rust-lang.org/book/ch05-03-method-syntax.html"""
 
 # ENUMS

solutions/07_structs/structs3.rs

@@ -1 +1,83 @@
-// Solutions will be available before the stable release. Thank you for testing the beta version 🥰
+#[derive(Debug)]
+struct Package {
+    sender_country: String,
+    recipient_country: String,
+    weight_in_grams: u32,
+}
+
+impl Package {
+    fn new(sender_country: String, recipient_country: String, weight_in_grams: u32) -> Self {
+        if weight_in_grams < 10 {
+            // This isn't how you should handle errors in Rust, but we will
+            // learn about error handling later.
+            panic!("Can't ship a package with weight below 10 grams");
+        }
+
+        Self {
+            sender_country,
+            recipient_country,
+            weight_in_grams,
+        }
+    }
+
+    fn is_international(&self) -> bool {
+        //                     ^^^^^^^ added
+        self.sender_country != self.recipient_country
+    }
+
+    fn get_fees(&self, cents_per_gram: u32) -> u32 {
+        //                                  ^^^^^^ added
+        self.weight_in_grams * cents_per_gram
+    }
+}
+
+fn main() {
+    // You can optionally experiment here.
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    #[should_panic]
+    fn fail_creating_weightless_package() {
+        let sender_country = String::from("Spain");
+        let recipient_country = String::from("Austria");
+
+        Package::new(sender_country, recipient_country, 5);
+    }
+
+    #[test]
+    fn create_international_package() {
+        let sender_country = String::from("Spain");
+        let recipient_country = String::from("Russia");
+
+        let package = Package::new(sender_country, recipient_country, 1200);
+
+        assert!(package.is_international());
+    }
+
+    #[test]
+    fn create_local_package() {
+        let sender_country = String::from("Canada");
+        let recipient_country = sender_country.clone();
+
+        let package = Package::new(sender_country, recipient_country, 1200);
+
+        assert!(!package.is_international());
+    }
+
+    #[test]
+    fn calculate_transport_fees() {
+        let sender_country = String::from("Spain");
+        let recipient_country = String::from("Spain");
+
+        let cents_per_gram = 3;
+
+        let package = Package::new(sender_country, recipient_country, 1500);
+
+        assert_eq!(package.get_fees(cents_per_gram), 4500);
+        assert_eq!(package.get_fees(cents_per_gram * 2), 9000);
+    }
+}