test function slice param

slice_pass_test.go

package main

import (
	"testing"
)

type myStruct struct {
	list []string
}

func BenchmarkSliceNoPointer(b *testing.B) {
	b.ReportAllocs()

	slice := make([]string, 1000)
	for i := 0; i < b.N; i++ {
		testNoPointer(slice)
	}
}

func BenchmarkSlicePointer(b *testing.B) {
	b.ReportAllocs()

	slice := make([]string, 1000)
	for i := 0; i < b.N; i++ {
		testPointer(&slice)
	}
}

func BenchmarkSliceWithStruct(b *testing.B) {
	b.ReportAllocs()

	slice := make([]string, 1000)
	s := &myStruct{list: slice}
	for i := 0; i < b.N; i++ {
		testPointerWithStruct(s)
	}
}

func testNoPointer(list []string) {
	for i := 0; i < 100; i++ {
		list[i] = "test string"
	}
}

func testPointer(list *([]string)) {
	for i := 0; i < 100; i++ {
		(*list)[i] = "test string"
	}
}

func testPointerWithStruct(s *myStruct) {
	for i := 0; i < 100; i++ {
		s.list[i] = "test string"
	}
}

──╼ go test -bench .
goos: darwin
goarch: amd64
pkg: my-test
BenchmarkSliceNoPointer-8    	37524774	        30.57 ns/op	       0 B/op	       0 allocs/op
BenchmarkSlicePointer-8      	11967490	       100.5 ns/op	       0 B/op	       0 allocs/op
BenchmarkSliceWithStruct-8   	11358862	       110.0 ns/op	       0 B/op	       0 allocs/op
PASS
ok  	my-test	5.065s