Add simulate unit test back in

balancer/catabalancer/catalyst_balancer_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"database/sql"
 	"encoding/json"
+	"fmt"
 	"testing"
 	"time"
 
@@ -415,3 +416,41 @@ func TestStreamTimeout(t *testing.T) {
 	nodes = selectTopNodes(c.createScoredNodes(s), "ingest", 0, 0, 1)
 	require.Empty(t, nodes)
 }
+
+func TestSimulate(t *testing.T) {
+	// update these values to test the lock contention with higher numbers of nodes etc
+	nodeCount := 1
+	streamsPerNode := 2
+	expectedResponseTime := 100 * time.Millisecond
+	loadBalanceCallCount := 5
+
+	db, mock, err := sqlmock.New()
+	require.NoError(t, err)
+	c := NewBalancer("node0", time.Second, time.Second, db)
+	var nodes []cluster.Member
+	for i := 0; i < nodeCount; i++ {
+		nodes = append(nodes, cluster.Member{Name: fmt.Sprintf("node%d", i)})
+	}
+	err = c.UpdateMembers(context.Background(), nodes)
+	require.NoError(t, err)
+
+	var s []NodeUpdateEvent
+	for i := 0; i < nodeCount; i++ {
+		nodeStats := NodeUpdateEvent{NodeID: fmt.Sprintf("node%d", i), NodeMetrics: NodeMetrics{Timestamp: time.Now()}}
+		var streams []string
+		for k := 0; k < streamsPerNode; k++ {
+			streams = append(streams, fmt.Sprintf("stream%d", k))
+		}
+		nodeStats.SetStreams(streams, nil)
+		s = append(s, nodeStats)
+	}
+
+	for j := 0; j < loadBalanceCallCount; j++ {
+		setNodeMetrics(t, mock, s)
+		start := time.Now()
+		_, _, err = c.GetBestNode(context.Background(), nil, "playbackID", "0", "0", "", false)
+		require.NoError(t, err)
+		require.LessOrEqual(t, time.Since(start), expectedResponseTime)
+		time.Sleep(10 * time.Millisecond)
+	}
+}