package jsondb
import (
"errors"
"io/ioutil"
"os"
"path"
"testing"
"github.com/stretchr/testify/require"
)
func TestWriteFileAtomically(t *testing.T) {
dir, err := ioutil.TempDir("", "jsondb-test-")
require.NoError(t, err)
defer func() {
err := os.RemoveAll(dir)
require.NoError(t, err)
}()
t.Run("success", func(t *testing.T) {
octopus := []byte("🐙\n")
// use an uncommon mode to check it's set correctly
perm := os.FileMode(0750)
err = writeFileAtomically(dir, "octopus", perm, func(f *os.File) error {
_, err := f.Write(octopus)
return err
})
require.NoError(t, err)
// ensure that there are no stray temporary files
infos, err := ioutil.ReadDir(dir)
require.NoError(t, err)
require.Equal(t, 1, len(infos))
require.Equal(t, "octopus", infos[0].Name())
require.Equal(t, perm, infos[0].Mode())
filename := path.Join(dir, "octopus")
contents, err := ioutil.ReadFile(filename)
require.NoError(t, err)
require.Equal(t, octopus, contents)
err = os.Remove(filename)
require.NoError(t, err)
})
t.Run("error", func(t *testing.T) {
err = writeFileAtomically(dir, "no-octopus", 0750, func(f *os.File) error {
return errors.New("something went wrong")
})
require.Error(t, err)
_, err := os.Stat(path.Join(dir, "no-octopus"))
require.Error(t, err)
// ensure there are no stray temporary files
infos, err := ioutil.ReadDir(dir)
require.NoError(t, err)
require.Equal(t, 0, len(infos))
})
}