add test for selectNodes()

balancer/balancer_select.go

@@ -45,8 +45,8 @@ func selectNodes(nodes []*Node, logger log.Logger, expected int, baselines []opt
 	// go through all base line until find expected selects
 	for _, b := range baselines {
 		baseline := time.Duration(b)
-		for i := 0; i < availableCount; i++ {
+		for i := count; i < availableCount; i++ {
-			if nodes[i].Weighted > baseline {
+			if nodes[i].Weighted >= baseline {
 				break
 			}
 			count = i + 1

balancer/balancer_select_test.go

@@ -0,0 +1,39 @@
+package balancer
+
+import (
+	"testing"
+
+	"github.com/sagernet/sing-box/option"
+)
+
+func TestSelectNodes(t *testing.T) {
+	nodes := []*Node{
+		{HealthCheckStats: HealthCheckStats{Weighted: 50}},
+		{HealthCheckStats: HealthCheckStats{Weighted: 70}},
+		{HealthCheckStats: HealthCheckStats{Weighted: 100}},
+		{HealthCheckStats: HealthCheckStats{Weighted: 110}},
+		{HealthCheckStats: HealthCheckStats{Weighted: 120}},
+		{HealthCheckStats: HealthCheckStats{Weighted: 150}},
+	}
+	tests := []struct {
+		expected  int
+		baselines []option.Duration
+		want      int
+	}{
+		{expected: -1, baselines: nil, want: 1},
+		{expected: 0, baselines: nil, want: 1},
+		{expected: 1, baselines: nil, want: 1},
+		{expected: 9999, baselines: nil, want: len(nodes)},
+		{expected: 0, baselines: []option.Duration{80, 100}, want: 2},
+		{expected: 2, baselines: []option.Duration{50, 100}, want: 2},
+		{expected: 3, baselines: []option.Duration{50, 100, 150}, want: 5},
+		{expected: 9999, baselines: []option.Duration{50, 100, 150}, want: len(nodes)},
+	}
+	for _, tt := range tests {
+		t.Run("", func(t *testing.T) {
+			if got := selectNodes(nodes, nil, tt.expected, tt.baselines); len(got) != tt.want {
+				t.Errorf("selectNodes() = %v, want %v", len(got), tt.want)
+			}
+		})
+	}
+}