diff --git a/src/session/Manager.cc b/src/session/Manager.cc
index 1792a212ed..6fdf275004 100644
--- a/src/session/Manager.cc
+++ b/src/session/Manager.cc
@@ -218,19 +218,34 @@ void Manager::Insert(Session* s, bool remove_existing)
 
 void Manager::Drain()
 	{
-	std::vector<const detail::Key*> keys;
-	keys.reserve(session_map.size());
-
-	for ( auto& entry : session_map )
-		keys.push_back(&(entry.first));
-	std::sort(keys.begin(), keys.end(), [](const detail::Key* a, const detail::Key* b) {
-		                                    return *a < *b; });
-
-	for ( const auto* k : keys )
+	// If a random seed was passed in, we're most likely in testing mode and need the
+	// order of the sessions to be consistent. Sort the keys to force that order
+	// every run.
+	if ( zeek::util::detail::have_random_seed() )
 		{
-		Session* tc = session_map.at(*k);
-		tc->Done();
-		tc->RemovalEvent();
+		std::vector<const detail::Key*> keys;
+		keys.reserve(session_map.size());
+
+		for ( auto& entry : session_map )
+			keys.push_back(&(entry.first));
+		std::sort(keys.begin(), keys.end(), [](const detail::Key* a, const detail::Key* b) {
+			                                    return *a < *b; });
+
+		for ( const auto* k : keys )
+			{
+			Session* tc = session_map.at(*k);
+			tc->Done();
+			tc->RemovalEvent();
+			}
+		}
+	else
+		{
+		for ( const auto& entry : session_map )
+			{
+			Session* tc = entry.second;
+			tc->Done();
+			tc->RemovalEvent();
+			}
 		}
 	}