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package iohelpers
import (
"bytes"
"io"
"os"
"testing"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
)
func TestLazyReadCloser(t *testing.T) {
r := newBufferCloser(bytes.NewBufferString("hello world"))
opened := false
l, ok := LazyReadCloser(func() (io.ReadCloser, error) {
opened = true
return r, nil
}).(*lazyReadCloser)
assert.True(t, ok)
assert.False(t, opened)
assert.Nil(t, l.r)
assert.False(t, r.closed)
p := make([]byte, 5)
n, err := l.Read(p)
require.NoError(t, err)
assert.True(t, opened)
assert.Equal(t, r, l.r)
assert.Equal(t, 5, n)
err = l.Close()
require.NoError(t, err)
assert.True(t, r.closed)
// test error propagation
l = LazyReadCloser(func() (io.ReadCloser, error) {
return nil, os.ErrNotExist
}).(*lazyReadCloser)
assert.Nil(t, l.r)
p = make([]byte, 5)
_, err = l.Read(p)
require.Error(t, err)
err = l.Close()
require.Error(t, err)
}
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