1 files changed, 23 insertions, 9 deletions

diff --git a/storage/src/tests/storageserver/mergethrottlertest.cpp b/storage/src/tests/storageserver/mergethrottlertest.cpp
index 5c192942521..e8f8e425af4 100644
--- a/storage/src/tests/storageserver/mergethrottlertest.cpp
+++ b/storage/src/tests/storageserver/mergethrottlertest.cpp
@@ -147,6 +147,14 @@ struct MergeThrottlerTest : Test {
 
     void fill_throttler_queue_with_n_commands(uint16_t throttler_index, size_t queued_count);
     void receive_chained_merge_with_full_queue(bool disable_queue_limits);
+
+    std::shared_ptr<api::MergeBucketCommand> peek_throttler_queue_top(size_t throttler_idx) {
+        auto& queue = _throttlers[throttler_idx]->getMergeQueue();
+        assert(!queue.empty());
+        auto merge = std::dynamic_pointer_cast<api::MergeBucketCommand>(queue.begin()->_msg);
+        assert(merge);
+        return merge;
+    }
 };
 
 MergeThrottlerTest::MergeThrottlerTest() = default;
@@ -789,7 +797,7 @@ TEST_F(MergeThrottlerTest, forward_queued_merge) {
     waitUntilMergeQueueIs(*_throttlers[0], 3, _messageWaitTime);
 
     // Merge queue state should not be touched by worker thread now
-    auto nextMerge = _throttlers[0]->getMergeQueue().begin()->_msg;
+    auto nextMerge = peek_throttler_queue_top(0);
 
     auto fwd = _topLinks[0]->getAndRemoveMessage(MessageType::MERGEBUCKET);
 
@@ -818,13 +826,12 @@ TEST_F(MergeThrottlerTest, forward_queued_merge) {
     fwd = _topLinks[0]->getAndRemoveMessage(MessageType::MERGEBUCKET);
 
     ASSERT_EQ(static_cast<const MergeBucketCommand&>(*fwd).getBucketId(),
-              static_cast<const MergeBucketCommand&>(*nextMerge).getBucketId());
+              nextMerge->getBucketId());
 
-    ASSERT_TRUE(static_cast<const MergeBucketCommand&>(*fwd).getNodes()
-                == static_cast<const MergeBucketCommand&>(*nextMerge).getNodes());
+    ASSERT_TRUE(static_cast<const MergeBucketCommand&>(*fwd).getNodes() == nextMerge->getNodes());
 
     // Ensure forwarded merge has a higher priority than the next queued one
-    EXPECT_LT(fwd->getPriority(), _throttlers[0]->getMergeQueue().begin()->_msg->getPriority());
+    EXPECT_LT(fwd->getPriority(), peek_throttler_queue_top(0)->getPriority());
 
     EXPECT_EQ(uint64_t(1), _throttlers[0]->getMetrics().chaining.ok.getValue());
 }
@@ -863,10 +870,8 @@ TEST_F(MergeThrottlerTest, execute_queued_merge) {
     waitUntilMergeQueueIs(throttler, 4, _messageWaitTime);
 
     // Merge queue state should not be touched by worker thread now
-    auto nextMerge = throttler.getMergeQueue().begin()->_msg;
-
-    ASSERT_EQ(BucketId(32, 0x1337),
-              dynamic_cast<const MergeBucketCommand&>(*nextMerge).getBucketId());
+    auto nextMerge = peek_throttler_queue_top(1);
+    ASSERT_EQ(BucketId(32, 0x1337), nextMerge->getBucketId());
 
     auto fwd = topLink.getAndRemoveMessage(MessageType::MERGEBUCKET);
 
@@ -1235,6 +1240,15 @@ TEST_F(MergeThrottlerTest, forwarded_merges_busy_bounced_if_queue_is_full_and_ch
     EXPECT_EQ(ReturnCode::BUSY, static_cast<MergeBucketReply&>(*reply).getResult().getResult());
 }
 
+TEST_F(MergeThrottlerTest, forwarded_merge_has_higher_pri_when_chain_limits_disabled) {
+    ASSERT_NO_FATAL_FAILURE(receive_chained_merge_with_full_queue(true));
+    size_t max_enqueued = _throttlers[1]->getMaxQueueSize();
+    waitUntilMergeQueueIs(*_throttlers[1], max_enqueued + 1, _messageWaitTime);
+
+    auto highest_pri_merge = peek_throttler_queue_top(1);
+    EXPECT_FALSE(highest_pri_merge->getChain().empty()); // Should be the forwarded merge
+}
+
 TEST_F(MergeThrottlerTest, broken_cycle) {
     std::vector<MergeBucketCommand::Node> nodes;
     nodes.push_back(1);