100 exercises to learn Rust

exercises/05_ticket_v2/15_outro/src/title.rs

@@ -0,0 +1,41 @@
+// TODO: Implement `TryFrom<String>` and `TryFrom<&str>` for the `TicketTitle` type,
+//   enforcing that the title is not empty and is not longer than 50 characters.
+//   Implement the traits required to make the tests pass too.
+
+pub struct TicketTitle(String);
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::convert::TryFrom;
+
+    #[test]
+    fn test_try_from_string() {
+        let title = TicketTitle::try_from("A title".to_string()).unwrap();
+        assert_eq!(title.0, "A title");
+    }
+
+    #[test]
+    fn test_try_from_empty_string() {
+        let err = TicketTitle::try_from("".to_string()).unwrap_err();
+        assert_eq!(err.to_string(), "The title cannot be empty");
+    }
+
+    #[test]
+    fn test_try_from_long_string() {
+        let title =
+            "A title that's definitely longer than what should be allowed in a development ticket"
+                .to_string();
+        let err = TicketTitle::try_from(title).unwrap_err();
+        assert_eq!(
+            err.to_string(),
+            "The title cannot be longer than 50 characters"
+        );
+    }
+
+    #[test]
+    fn test_try_from_str() {
+        let title = TicketTitle::try_from("A title").unwrap();
+        assert_eq!(title.0, "A title");
+    }
+}