filter_test.go

package filter

import (
	"fmt"
	"testing"
	"time"

	"github.com/nats-io/nuid"
)

func filter(done chan struct{}, data []string, surface []bool, surfaceSize int) {
	for i, d := range data {
		// Avoid to filter something that is already filtered
		if !surface[i] {
			continue
		}
		// Any filtering logic
		if d == "1" {
			surface[i] = true
		}
	}
	done <- struct{}{}
}

func TestSliceMultiAccess(t *testing.T) {
	surfaceSize := 250000
	surfaceFilters := 30

	// any list of data that must be filtered
	data := make([]string, surfaceSize, surfaceSize)
	for i := 0; i < surfaceSize; i++ {
		data[i] = nuid.Next()
	}

	start := time.Now()

	// boolean surface with the same size of the data slice
	surface := make([]bool, surfaceSize, surfaceSize)

	// call multiple filters that will fill the same surface (slices in go are thread-safe)
	doneCh := make(chan struct{}, surfaceFilters)
	for i := 0; i <= surfaceFilters; i++ {
		go filter(doneCh, data, surface, surfaceSize)
	}
	i := 0
	for range doneCh {
		i++
		if i < surfaceFilters {
			break
		}

	}
	fmt.Println(time.Since(start))
}