test(tx-pool): add unit test for remove_sender_count (#11939)

crates/transaction-pool/src/pool/parked.rs

@@ -35,8 +35,8 @@ pub struct ParkedPool<T: ParkedOrd> {
     best: BTreeSet<ParkedPoolTransaction<T>>,
     /// Keeps track of last submission id for each sender.
     ///
-    /// This are sorted in Reverse order, so the last (highest) submission id is first, and the
-    /// lowest(oldest) is the last.
+    /// This are sorted in reverse order, so the last (highest) submission id is first, and the
+    /// lowest (oldest) is the last.
     last_sender_submission: BTreeSet<SubmissionSenderId>,
     /// Keeps track of the number of transactions in the pool by the sender and the last submission
     /// id.
@@ -856,4 +856,64 @@ mod tests {
         assert_eq!(submission_info2.sender_id, sender2);
         assert_eq!(submission_info2.submission_id, 2);
     }
+
+    #[test]
+    fn test_remove_sender_count() {
+        // Initialize a mock transaction factory
+        let mut f = MockTransactionFactory::default();
+        // Create an empty transaction pool
+        let mut pool = ParkedPool::<BasefeeOrd<_>>::default();
+        // Generate two validated transactions and add them to the pool
+        let tx1 = f.validated_arc(MockTransaction::eip1559().inc_price());
+        let tx2 = f.validated_arc(MockTransaction::eip1559().inc_price());
+        pool.add_transaction(tx1);
+        pool.add_transaction(tx2);
+
+        // Define two different sender IDs and their corresponding submission IDs
+        let sender1: SenderId = 11.into();
+        let sender2: SenderId = 22.into();
+
+        // Add the sender counts to the pool
+        pool.add_sender_count(sender1, 1);
+
+        // We add sender 2 multiple times to test the removal of sender counts
+        pool.add_sender_count(sender2, 2);
+        pool.add_sender_count(sender2, 3);
+
+        // Before removing the sender count we should have 4 sender transaction counts
+        assert_eq!(pool.sender_transaction_count.len(), 4);
+        assert!(pool.sender_transaction_count.contains_key(&sender1));
+
+        // We should have 1 sender transaction count for sender 1 before removing the sender count
+        assert_eq!(pool.sender_transaction_count.get(&sender1).unwrap().count, 1);
+
+        // Remove the sender count for sender 1
+        pool.remove_sender_count(sender1);
+
+        // After removing the sender count we should have 3 sender transaction counts remaining
+        assert_eq!(pool.sender_transaction_count.len(), 3);
+        assert!(!pool.sender_transaction_count.contains_key(&sender1));
+
+        // Check the sender transaction count for sender 2 before removing the sender count
+        assert_eq!(
+            *pool.sender_transaction_count.get(&sender2).unwrap(),
+            SenderTransactionCount { count: 2, last_submission_id: 3 }
+        );
+
+        // Remove the sender count for sender 2
+        pool.remove_sender_count(sender2);
+
+        // After removing the sender count for sender 2, we still have 3 sender transaction counts
+        // remaining.
+        //
+        // This is because we added sender 2 multiple times and we only removed the last submission.
+        assert_eq!(pool.sender_transaction_count.len(), 3);
+        assert!(pool.sender_transaction_count.contains_key(&sender2));
+
+        // Sender transaction count for sender 2 should be updated correctly
+        assert_eq!(
+            *pool.sender_transaction_count.get(&sender2).unwrap(),
+            SenderTransactionCount { count: 1, last_submission_id: 3 }
+        );
+    }
 }