its: Added IssueBlockLink entity

its/crates/domain/src/domain/entity.rs

@@ -1,3 +1,5 @@
 mod issue;
+mod issue_block_link;
 
 pub use self::issue::*;
+pub use self::issue_block_link::*;

its/crates/domain/src/domain/entity/issue_block_link.rs

@@ -0,0 +1,60 @@
+use crate::{IssueBlockLinkId, IssueBlockLinkStatus, IssueId};
+
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct IssueBlockLink {
+    id: IssueBlockLinkId,
+    status: IssueBlockLinkStatus,
+}
+
+impl IssueBlockLink {
+    pub(crate) fn new(id: IssueBlockLinkId) -> Self {
+        Self {
+            id,
+            status: IssueBlockLinkStatus::Blocked,
+        }
+    }
+
+    pub fn issue_id(&self) -> &IssueId {
+        self.id.issue_id()
+    }
+
+    pub fn blocked_issue_id(&self) -> &IssueId {
+        self.id.blocked_issue_id()
+    }
+
+    pub fn is_blocked(&self) -> bool {
+        self.status == IssueBlockLinkStatus::Blocked
+    }
+
+    pub(crate) fn block(&mut self) {
+        self.status = IssueBlockLinkStatus::Blocked;
+    }
+
+    pub(crate) fn unblock(&mut self) {
+        self.status = IssueBlockLinkStatus::Unblocked;
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::str::FromStr;
+
+    use super::*;
+
+    #[test]
+    fn test() -> anyhow::Result<()> {
+        let id = IssueBlockLinkId::from_str("1 -> 2")?;
+        let mut link = IssueBlockLink::new(id.clone());
+        assert_eq!(link.issue_id(), id.issue_id());
+        assert_eq!(link.blocked_issue_id(), id.blocked_issue_id());
+        assert!(link.is_blocked());
+
+        link.unblock();
+        assert!(!link.is_blocked());
+
+        link.block();
+        assert!(link.is_blocked());
+
+        Ok(())
+    }
+}