Go Benchmarking example for string concatenation. Use with `go test -bench=.`

string_concat.go

package string_concat

import (
	"bytes"
)

func ConcatOperator(original *string, concat string) {
	// This could be written as 'return *original + concat' but wanted to confirm no special
	// compiler optimizations existed for concatenating a string to itself.
	*original = *original + concat
}

func SelfConcatOperator(input string, n int) string {
	output := ""
	for i := 0; i < n; i++ {
		ConcatOperator(&output, input)
	}
	return output
}

func ConcatBuffer(original *bytes.Buffer, concat string) {
	original.WriteString(concat)
}

func SelfConcatBuffer(input string, n int) string {
	var output bytes.Buffer
	for i := 0; i < n; i++ {
		ConcatBuffer(&output, input)
	}
	return string(output.Bytes())
}

string_concat_test.go

package string_concat

import "testing"

const TEST_STRING = "test"

func benchmarkConcat(size int, SelfConcat func(string, int) string, b *testing.B) {
	for n := 0; n < b.N; n++ {
		SelfConcat(TEST_STRING, size)
	}
}

func BenchmarkConcatOperator2(b *testing.B)      { benchmarkConcat(2, SelfConcatOperator, b) }
func BenchmarkConcatOperator10(b *testing.B)     { benchmarkConcat(10, SelfConcatOperator, b) }
func BenchmarkConcatOperator100(b *testing.B)    { benchmarkConcat(100, SelfConcatOperator, b) }
func BenchmarkConcatOperator1000(b *testing.B)   { benchmarkConcat(1000, SelfConcatOperator, b) }
func BenchmarkConcatOperator10000(b *testing.B)  { benchmarkConcat(10000, SelfConcatOperator, b) }
func BenchmarkConcatOperator100000(b *testing.B) { benchmarkConcat(100000, SelfConcatOperator, b) }

func BenchmarkConcatBuffer2(b *testing.B)      { benchmarkConcat(2, SelfConcatBuffer, b) }
func BenchmarkConcatBuffer10(b *testing.B)     { benchmarkConcat(10, SelfConcatBuffer, b) }
func BenchmarkConcatBuffer100(b *testing.B)    { benchmarkConcat(100, SelfConcatBuffer, b) }
func BenchmarkConcatBuffer1000(b *testing.B)   { benchmarkConcat(1000, SelfConcatBuffer, b) }
func BenchmarkConcatBuffer10000(b *testing.B)  { benchmarkConcat(10000, SelfConcatBuffer, b) }
func BenchmarkConcatBuffer100000(b *testing.B) { benchmarkConcat(100000, SelfConcatBuffer, b) }