syncthing/lib/osutil/atomic_test.go

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// Copyright (C) 2015 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.
package osutil
import (
"bytes"
"io/ioutil"
"os"
"path/filepath"
"testing"
)
func TestCreateAtomicCreate(t *testing.T) {
os.RemoveAll("testdata")
defer os.RemoveAll("testdata")
if err := os.Mkdir("testdata", 0755); err != nil {
t.Fatal(err)
}
w, err := CreateAtomic("testdata/file")
if err != nil {
t.Fatal(err)
}
n, err := w.Write([]byte("hello"))
if err != nil {
t.Fatal(err)
}
if n != 5 {
t.Fatal("written bytes", n, "!= 5")
}
if _, err := ioutil.ReadFile("testdata/file"); err == nil {
t.Fatal("file should not exist")
}
if err := w.Close(); err != nil {
t.Fatal(err)
}
bs, err := ioutil.ReadFile("testdata/file")
if err != nil {
t.Fatal(err)
}
if !bytes.Equal(bs, []byte("hello")) {
t.Error("incorrect data")
}
}
func TestCreateAtomicReplace(t *testing.T) {
testCreateAtomicReplace(t, 0666)
}
func TestCreateAtomicReplaceReadOnly(t *testing.T) {
testCreateAtomicReplace(t, 0444) // windows compatible read-only bits
}
func testCreateAtomicReplace(t *testing.T, oldPerms os.FileMode) {
t.Helper()
testdir, err := ioutil.TempDir("", "syncthing")
if err != nil {
t.Fatal(err)
}
testfile := filepath.Join(testdir, "testfile")
os.RemoveAll(testdir)
defer os.RemoveAll(testdir)
if err := os.Mkdir(testdir, 0755); err != nil {
t.Fatal(err)
}
if err := ioutil.WriteFile(testfile, []byte("some old data"), oldPerms); err != nil {
t.Fatal(err)
}
// Go < 1.14 has a bug in WriteFile where it does not use the requested
// permissions on Windows. Chmod to make sure.
if err := os.Chmod(testfile, oldPerms); err != nil {
t.Fatal(err)
}
// Trust, but verify.
if info, err := os.Stat(testfile); err != nil {
t.Fatal(err)
} else if info.Mode() != oldPerms {
t.Fatalf("Wrong perms 0%o", info.Mode())
}
w, err := CreateAtomic(testfile)
if err != nil {
t.Fatal(err)
}
if _, err := w.Write([]byte("hello")); err != nil {
t.Fatal(err)
}
if err := w.Close(); err != nil {
t.Fatal(err)
}
bs, err := ioutil.ReadFile(testfile)
if err != nil {
t.Fatal(err)
}
if !bytes.Equal(bs, []byte("hello")) {
t.Error("incorrect data")
}
if info, err := os.Stat(testfile); err != nil {
t.Fatal(err)
} else if info.Mode() != oldPerms {
t.Fatalf("Perms changed during atomic write: 0%o", info.Mode())
}
}