package trading

import (
	"fmt"
	"testing"
)

func TestSliceCap(t *testing.T) {
	Max, MaxCap := 1000, 1280
	_ = MaxCap
	var arr []int
	prevCap := cap(arr)
	for i := range 1600 {
		ele := i
		if len(arr) < MaxCap {
			arr = append(arr, ele)
		} else {
			length := len(arr)
			copy(arr, arr[length-Max+1:])
			arr[Max-1] = ele
			arr = arr[:Max]
			fmt.Printf("move=%d, %d, arr=(%d~%d)\n", i, len(arr), arr[0], arr[len(arr)-1])
		}

		c := cap(arr)
		if c != prevCap {
			// 发生扩容
			prevCap = c
			fmt.Printf("i=%d, cap=%d, len=%d\n", i, c, len(arr))
		}
	}
	fmt.Println("----------------------------------------------------------")
	fmt.Println(arr)
}