initial commit

exercises/03_ticket_v1/04_visibility/Cargo.toml

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+[package]
+name = "visibility"
+version = "0.1.0"
+edition = "2021"

exercises/03_ticket_v1/04_visibility/src/lib.rs

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+mod ticket {
+    struct Ticket {
+        title: String,
+        description: String,
+        status: String,
+    }
+
+    impl Ticket {
+        fn new(title: String, description: String, status: String) -> Ticket {
+            if title.is_empty() {
+                panic!("Title cannot be empty");
+            }
+            if title.len() > 50 {
+                panic!("Title cannot be longer than 50 bytes");
+            }
+            if description.is_empty() {
+                panic!("Description cannot be empty");
+            }
+            if description.len() > 500 {
+                panic!("Description cannot be longer than 500 bytes");
+            }
+            if status != "To-Do" && status != "In Progress" && status != "Done" {
+                panic!("Only `To-Do`, `In Progress`, and `Done` statuses are allowed");
+            }
+
+            Ticket {
+                title,
+                description,
+                status,
+            }
+        }
+    }
+}
+
+// TODO: **Exceptionally**, you'll be modifying both the `ticket` module and the `tests` module
+//  in this exercise.
+#[cfg(test)]
+mod tests {
+    // TODO: Add the necessary `pub` modifiers in the parent module to remove the compiler
+    //  errors about the use statement below.
+    use super::ticket::Ticket;
+
+    // Be careful though! We don't want this function to compile after you have changed
+    // visibility to make the use statement compile!
+    // Once you have verified that it indeed doesn't compile, comment it out.
+    fn should_not_be_possible() {
+        let ticket = Ticket::new("A title".into(), "A description".into(), "To-Do".into());
+
+        // You should be seeing this error when trying to run this exercise:
+        //
+        // error[E0616]: field `description` of struct `Ticket` is private
+        //    |
+        //    |              assert_eq!(ticket.description, "A description");
+        //    |                         ^^^^^^^^^^^^^^^^^^
+        //
+        // TODO: Once you have verified that the below does not compile,
+        //   comment the line out to move on to the next exercise!
+        assert_eq!(ticket.description, "A description");
+    }
+
+    fn encapsulation_cannot_be_violated() {
+        // This should be impossible as well, with a similar error as the one encountered above.
+        // (It will throw a compilation error only after you have commented the faulty line
+        // in the previous test - next compilation stage!)
+        //
+        // This proves that `Ticket::new` is now the only way to get a `Ticket` instance.
+        // It's impossible to create a ticket with an illegal title or description!
+        //
+        // TODO: Once you have verified that the below does not compile,
+        //   comment the lines out to move on to the next exercise!
+        let ticket = Ticket {
+            title: "A title".into(),
+            description: "A description".into(),
+            status: "To-Do".into(),
+        };
+    }
+}