package mergechannel

import (
	"testing"

	"github.com/stretchr/testify/assert"
)

func TestMerge(t *testing.T) {
	a := make(chan int, 5)
	b := make(chan int, 5)

	for i := 0; i < 5; i++ {
		a <- i
		b <- i
	}

	merged, err := merge(a, b)
	assert.Nil(t, err)

	close(a)
	close(b)

	sum := 0
	for v := range merged {
		sum += v
	}
	assert.Equal(t, sum, 20)
}

func TestInsufficient(t *testing.T) {
	a := make(chan int)

	_, err := merge(a)
	assert.Equal(t, err, ErrInsufficientChannels)
}