Use generational stack for idle connections

internal/genstack/gen_stack_test.go

@@ -0,0 +1,90 @@
+package genstack
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func requirePopEmpty[T any](t testing.TB, s *GenStack[T]) {
+	v, ok := s.Pop()
+	require.False(t, ok)
+	require.Zero(t, v)
+}
+
+func requirePop[T any](t testing.TB, s *GenStack[T], expected T) {
+	v, ok := s.Pop()
+	require.True(t, ok)
+	require.Equal(t, expected, v)
+}
+
+func TestGenStack_Empty(t *testing.T) {
+	s := NewGenStack[int]()
+	requirePopEmpty(t, s)
+}
+
+func TestGenStack_SingleGen(t *testing.T) {
+	r := require.New(t)
+	s := NewGenStack[int]()
+
+	s.Push(1)
+	s.Push(2)
+	r.Equal(2, s.Len())
+
+	requirePop(t, s, 2)
+	requirePop(t, s, 1)
+	requirePopEmpty(t, s)
+}
+
+func TestGenStack_TwoGen(t *testing.T) {
+	r := require.New(t)
+	s := NewGenStack[int]()
+
+	s.Push(3)
+	s.Push(4)
+	s.Push(5)
+	r.Equal(3, s.Len())
+	s.NextGen()
+	r.Equal(3, s.Len())
+	s.Push(6)
+	s.Push(7)
+	r.Equal(5, s.Len())
+
+	requirePop(t, s, 5)
+	requirePop(t, s, 4)
+	requirePop(t, s, 3)
+	requirePop(t, s, 7)
+	requirePop(t, s, 6)
+	requirePopEmpty(t, s)
+}
+
+func TestGenStack_MuptiGen(t *testing.T) {
+	r := require.New(t)
+	s := NewGenStack[int]()
+
+	s.Push(10)
+	s.Push(11)
+	s.Push(12)
+	r.Equal(3, s.Len())
+	s.NextGen()
+	r.Equal(3, s.Len())
+	s.Push(13)
+	s.Push(14)
+	r.Equal(5, s.Len())
+	s.NextGen()
+	r.Equal(5, s.Len())
+	s.Push(15)
+	s.Push(16)
+	s.Push(17)
+	r.Equal(8, s.Len())
+
+	requirePop(t, s, 12)
+	requirePop(t, s, 11)
+	requirePop(t, s, 10)
+	requirePop(t, s, 14)
+	requirePop(t, s, 13)
+	requirePop(t, s, 17)
+	requirePop(t, s, 16)
+	requirePop(t, s, 15)
+	requirePopEmpty(t, s)
+}