Fix: return tweet id that is not valid

src/repositories/relevant_tweet.rs

@@ -93,7 +93,7 @@ impl RelevantTweetRepository {
     }
 
     pub async fn get_newest_tweet_id(&self) -> Result<Option<String>, DbError> {
-        let row = sqlx::query("SELECT id FROM relevant_tweets ORDER BY created_at DESC LIMIT 1")
+        let row = sqlx::query("SELECT id FROM relevant_tweets WHERE created_at >= NOW() - INTERVAL '7 days' ORDER BY created_at DESC LIMIT 1")
             .fetch_optional(&self.pool)
             .await?;
 
@@ -244,7 +244,7 @@ mod tests {
         utils::test_db::reset_database,
         Config,
     };
-    use chrono::Utc;
+    use chrono::{Duration, Utc};
     use sqlx::PgPool;
 
     // --- Helpers to create dummy data ---
@@ -291,7 +291,6 @@ mod tests {
     }
 
     // --- Tests ---
-
     #[tokio::test]
     async fn test_upsert_and_find_by_id() {
         let (repo, author_repo) = setup_test_repository().await;
@@ -347,4 +346,39 @@ mod tests {
         assert!(existing.contains("t2"));
         assert!(!existing.contains("t3"));
     }
+
+    #[tokio::test]
+    async fn test_get_newest_tweet_id_returns_none_when_no_recent_tweets() {
+        let (repo, author_repo) = setup_test_repository().await;
+        let author_id = "author_old";
+        seed_author(&author_repo, author_id, "stale_user").await;
+
+        let mut old_tweet = create_payload("tweet_old", author_id, "stale tweet");
+        old_tweet.created_at = Utc::now() - Duration::days(8);
+        repo.upsert_many(&vec![old_tweet]).await.unwrap();
+
+        let newest_tweet_id = repo.get_newest_tweet_id().await.unwrap();
+        assert_eq!(
+            newest_tweet_id, None,
+            "Should return None when no tweet is within the last 7 days"
+        );
+    }
+
+    #[tokio::test]
+    async fn test_get_newest_tweet_id_returns_some_when_recent_tweet_exists() {
+        let (repo, author_repo) = setup_test_repository().await;
+        let author_id = "author_recent";
+        seed_author(&author_repo, author_id, "active_user").await;
+
+        let mut recent_tweet = create_payload("tweet_recent", author_id, "recent tweet");
+        recent_tweet.created_at = Utc::now() - Duration::days(2);
+        repo.upsert_many(&vec![recent_tweet]).await.unwrap();
+
+        let newest_tweet_id = repo.get_newest_tweet_id().await.unwrap();
+        assert_eq!(
+            newest_tweet_id,
+            Some("tweet_recent".to_string()),
+            "Should return the newest tweet id when at least one tweet is within the last 7 days"
+        );
+    }
 }