Merge pull request #138 from teloxide/text_getter_for_message_entity

add method text_from for MessageEntity

src/types/message_entity.rs

@@ -1,6 +1,6 @@
 use serde::{Deserialize, Serialize};
 
-use crate::types::User;
+use crate::types::{User, Message};
 
 /// This object represents one special entity in a text message. For example,
 /// hashtags, usernames, URLs, etc.
@@ -39,21 +39,83 @@ pub enum MessageEntityKind {
     Strikethrough,
 }
 
-#[test]
-fn recursive_kind() {
-    use serde_json::from_str;
-
-    assert_eq!(
-        MessageEntity {
-            kind: MessageEntityKind::TextLink {
-                url: "ya.ru".into()
-            },
-            offset: 1,
-            length: 2,
-        },
-        from_str::<MessageEntity>(
-            r#"{"type":"text_link","url":"ya.ru","offset":1,"length":2}"#
-        )
-        .unwrap()
-    );
+impl MessageEntity {
+    pub fn text_from(&self, message: &Message) -> Option<String> {
+        let text = message.text();
+        Some(String::from(&text?[self.offset..self.offset+self.length]))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::types::{Chat, ChatKind, MessageKind, Sender, ForwardKind, MediaKind};
+
+    #[test]
+    fn recursive_kind() {
+        use serde_json::from_str;
+
+        assert_eq!(
+            MessageEntity {
+                kind: MessageEntityKind::TextLink {
+                    url: "ya.ru".into()
+                },
+                offset: 1,
+                length: 2,
+            },
+            from_str::<MessageEntity>(
+                r#"{"type":"text_link","url":"ya.ru","offset":1,"length":2}"#
+            )
+            .unwrap()
+        );
+    }
+
+    #[test]
+    fn text_from() {
+        let message = message();
+        let expected = Some("yes".to_string());
+        let entity = message.entities().unwrap()[0].clone();
+        let actual = entity.text_from(&message);
+        assert_eq!(actual, expected);
+    }
+
+    fn message() -> Message {
+        Message {
+            id: 0,
+            date: 0,
+            chat: Chat {
+                id: 0,
+                kind: ChatKind::Private {
+                    type_: (),
+                    username: None,
+                    first_name: None,
+                    last_name: None,
+                },
+                photo: None,
+            },
+            kind: MessageKind::Common {
+                from: Sender::User(User {
+                    id: 0,
+                    is_bot: false,
+                    first_name: "".to_string(),
+                    last_name: None,
+                    username: None,
+                    language_code: None,
+                }),
+                forward_kind: ForwardKind::Origin {
+                    reply_to_message: None,
+                },
+                edit_date: None,
+                media_kind: MediaKind::Text {
+                    text: "no yes no".to_string(),
+                    entities: vec![MessageEntity {
+                        kind: MessageEntityKind::Mention,
+                        offset: 3,
+                        length: 3
+                    }],
+                },
+                reply_markup: None,
+            },
+        }
+    }
 }