Parse data from incoming request

src/domain/subscriber_name.rs

@@ -0,0 +1,69 @@
+use unicode_segmentation::UnicodeSegmentation;
+
+#[derive(Debug)]
+pub struct SubscriberName(String);
+
+impl SubscriberName {
+    pub fn parse(s: String) -> Result<Self, String> {
+        let is_empty_or_whitespace = s.trim().is_empty();
+        let is_too_long = s.graphemes(true).count() > 256;
+        let forbidden_characters = ['/', '(', ')', '"', '<', '>', '\\', '{', '}'];
+        let contains_forbidden_characters = s.chars().any(|g| forbidden_characters.contains(&g));
+
+        if is_empty_or_whitespace || is_too_long || contains_forbidden_characters {
+            Err(format!("{} is not a valid subscriber name.", s))
+        } else {
+            Ok(Self(s))
+        }
+    }
+}
+
+impl AsRef<str> for SubscriberName {
+    fn as_ref(&self) -> &str {
+        self.0.as_str()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::domain::SubscriberName;
+    use claims::{assert_err, assert_ok};
+
+    #[test]
+    fn a_256_grapheme_long_name_is_valid() {
+        let name = "ê".repeat(256);
+        assert_ok!(SubscriberName::parse(name));
+    }
+
+    #[test]
+    fn a_name_longer_than_256_graphemes_is_rejected() {
+        let name = "ê".repeat(257);
+        assert_err!(SubscriberName::parse(name));
+    }
+
+    #[test]
+    fn a_whitespace_only_name_is_rejected() {
+        let name = "\n  \t   ".to_string();
+        assert_err!(SubscriberName::parse(name));
+    }
+
+    #[test]
+    fn empty_string_is_rejected() {
+        let name = "".to_string();
+        assert_err!(SubscriberName::parse(name));
+    }
+
+    #[test]
+    fn a_name_containing_invalid_character_is_rejected() {
+        for name in ['/', '(', ')', '"', '<', '>', '\\', '{', '}'] {
+            let name = name.to_string();
+            assert_err!(SubscriberName::parse(name));
+        }
+    }
+
+    #[test]
+    fn a_valid_name_is_parsed_successfully() {
+        let name = "Alphonse".to_string();
+        assert_ok!(SubscriberName::parse(name));
+    }
+}