misc_test.go

package iter_test

import (
	"testing"

	"github.com/disksing/iter/v2"
	. "github.com/disksing/iter/v2"
	"github.com/disksing/iter/v2/algo"
	"github.com/stretchr/testify/assert"
)

func TestMisc(t *testing.T) {
	assert := assert.New(t)

	it := IotaReader(100)
	assert.Equal(it.Read(), 100)
	assert.False(it.Eq(IotaReader(100)))
	it = it.Next()
	assert.Equal(it.Read(), 101)

	it2 := RepeatReader(100)
	assert.Equal(it2.Read(), 100)
	assert.False(it2.Eq(RepeatReader(100)))
	it2 = it2.Next()
	assert.Equal(it2.Read(), 100)

	g := IotaGenerator(100)
	assert.Equal(g(), 100)
	assert.Equal(g(), 101)
	g = RepeatGenerator(100)
	assert.Equal(g(), 100)
	assert.Equal(g(), 100)
}

func TestChanIterator(t *testing.T) {
	assert := assert.New(t)
	ch := make(chan int)
	go func() {
		algo.CopyN[int](IotaReader(1), 10, ChanWriter(ch))
		close(ch)
	}()
	assert.Equal(algo.Accumulate(ChanReader(ch), nil, 0), 55)

	ch = make(chan int)
	close(ch)
	assert.True(ChanReader(ch).Eq(nil))

	ch = make(chan int, 1)
	ch <- 100
	assert.Equal(ChanReader(ch).Read(), 100)

	ch = make(chan int, 2)
	ch <- 42
	ch <- 43
	it := ChanReader(ch)
	it.Next()
	assert.Equal(it.Read(), 43)

	ch = make(chan int, 10)
	algo.CopyN[int](IotaReader(1), 5, ChanWriter(ch))
	close(ch)
	it = ChanReader(ch)
	it = iter.AdvanceN[int](it, 3)
	assert.Equal(it.Read(), 4)
	assert.Equal(iter.Distance[int](it, nil), 2)

	ch = make(chan int)
	w := ChanWriter(ch)
	// See: https://github.com/golang/go/issues/51700
	// assert.Panics(func() { iter.AdvanceN[int](w, 1) })
	assert.Panics(func() { iter.Distance[int](w, nil) })
}