fusego/samples/memfs/posix_test.go

421 lines
9.8 KiB
Go

// Copyright 2015 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Tests for the behavior of os.File objects on plain old posix file systems,
// for use in verifying the intended behavior of memfs.
package memfs_test
import (
"io"
"io/ioutil"
"os"
"path"
"runtime"
"testing"
. "github.com/jacobsa/oglematchers"
. "github.com/jacobsa/ogletest"
)
func TestPosix(t *testing.T) { RunTests(t) }
////////////////////////////////////////////////////////////////////////
// Helpers
////////////////////////////////////////////////////////////////////////
func getFileOffset(f *os.File) (offset int64, err error) {
const relativeToCurrent = 1
offset, err = f.Seek(0, relativeToCurrent)
return
}
////////////////////////////////////////////////////////////////////////
// Boilerplate
////////////////////////////////////////////////////////////////////////
type PosixTest struct {
// A temporary directory.
dir string
// Files to close when tearing down. Nil entries are skipped.
toClose []io.Closer
}
var _ SetUpInterface = &PosixTest{}
var _ TearDownInterface = &PosixTest{}
func init() { RegisterTestSuite(&PosixTest{}) }
func (t *PosixTest) SetUp(ti *TestInfo) {
var err error
// Create a temporary directory.
t.dir, err = ioutil.TempDir("", "posix_test")
if err != nil {
panic(err)
}
}
func (t *PosixTest) TearDown() {
// Close any files we opened.
for _, c := range t.toClose {
if c == nil {
continue
}
err := c.Close()
if err != nil {
panic(err)
}
}
// Remove the temporary directory.
err := os.RemoveAll(t.dir)
if err != nil {
panic(err)
}
}
////////////////////////////////////////////////////////////////////////
// Test functions
////////////////////////////////////////////////////////////////////////
func (t *PosixTest) WriteOverlapsEndOfFile() {
var err error
var n int
// Create a file.
f, err := os.Create(path.Join(t.dir, "foo"))
t.toClose = append(t.toClose, f)
AssertEq(nil, err)
// Make it 4 bytes long.
err = f.Truncate(4)
AssertEq(nil, err)
// Write the range [2, 6).
n, err = f.WriteAt([]byte("taco"), 2)
AssertEq(nil, err)
AssertEq(4, n)
// Read the full contents of the file.
contents, err := ioutil.ReadAll(f)
AssertEq(nil, err)
ExpectEq("\x00\x00taco", string(contents))
}
func (t *PosixTest) WriteStartsAtEndOfFile() {
var err error
var n int
// Create a file.
f, err := os.Create(path.Join(t.dir, "foo"))
t.toClose = append(t.toClose, f)
AssertEq(nil, err)
// Make it 2 bytes long.
err = f.Truncate(2)
AssertEq(nil, err)
// Write the range [2, 6).
n, err = f.WriteAt([]byte("taco"), 2)
AssertEq(nil, err)
AssertEq(4, n)
// Read the full contents of the file.
contents, err := ioutil.ReadAll(f)
AssertEq(nil, err)
ExpectEq("\x00\x00taco", string(contents))
}
func (t *PosixTest) WriteStartsPastEndOfFile() {
var err error
var n int
// Create a file.
f, err := os.Create(path.Join(t.dir, "foo"))
t.toClose = append(t.toClose, f)
AssertEq(nil, err)
// Write the range [2, 6).
n, err = f.WriteAt([]byte("taco"), 2)
AssertEq(nil, err)
AssertEq(4, n)
// Read the full contents of the file.
contents, err := ioutil.ReadAll(f)
AssertEq(nil, err)
ExpectEq("\x00\x00taco", string(contents))
}
func (t *PosixTest) WriteStartsPastEndOfFile_AppendMode() {
var err error
var n int
// Create a file.
f, err := os.OpenFile(
path.Join(t.dir, "foo"),
os.O_RDWR|os.O_APPEND|os.O_CREATE,
0600)
t.toClose = append(t.toClose, f)
AssertEq(nil, err)
// Write three bytes.
n, err = f.Write([]byte("111"))
AssertEq(nil, err)
AssertEq(3, n)
// Write at offset six.
n, err = f.WriteAt([]byte("222"), 6)
AssertEq(nil, err)
AssertEq(3, n)
// Read the full contents of the file.
//
// Linux's support for pwrite is buggy; the pwrite(2) man page says this:
//
// POSIX requires that opening a file with the O_APPEND flag should have
// no affect on the location at which pwrite() writes data. However, on
// Linux, if a file is opened with O_APPEND, pwrite() appends data to
// the end of the file, regardless of the value of offset.
//
contents, err := ioutil.ReadFile(f.Name())
AssertEq(nil, err)
if runtime.GOOS == "linux" {
ExpectEq("111222", string(contents))
} else {
ExpectEq("111\x00\x00\x00222", string(contents))
}
}
func (t *PosixTest) WriteAtDoesntChangeOffset_NotAppendMode() {
var err error
var n int
// Create a file.
f, err := os.Create(path.Join(t.dir, "foo"))
t.toClose = append(t.toClose, f)
AssertEq(nil, err)
// Make it 16 bytes long.
err = f.Truncate(16)
AssertEq(nil, err)
// Seek to offset 4.
_, err = f.Seek(4, 0)
AssertEq(nil, err)
// Write the range [10, 14).
n, err = f.WriteAt([]byte("taco"), 2)
AssertEq(nil, err)
AssertEq(4, n)
// We should still be at offset 4.
offset, err := getFileOffset(f)
AssertEq(nil, err)
ExpectEq(4, offset)
}
func (t *PosixTest) WriteAtDoesntChangeOffset_AppendMode() {
var err error
var n int
// Create a file in append mode.
f, err := os.OpenFile(
path.Join(t.dir, "foo"),
os.O_RDWR|os.O_APPEND|os.O_CREATE,
0600)
t.toClose = append(t.toClose, f)
AssertEq(nil, err)
// Make it 16 bytes long.
err = f.Truncate(16)
AssertEq(nil, err)
// Seek to offset 4.
_, err = f.Seek(4, 0)
AssertEq(nil, err)
// Write the range [10, 14).
n, err = f.WriteAt([]byte("taco"), 2)
AssertEq(nil, err)
AssertEq(4, n)
// We should still be at offset 4.
offset, err := getFileOffset(f)
AssertEq(nil, err)
ExpectEq(4, offset)
}
func (t *PosixTest) AppendMode() {
var err error
var n int
var off int64
buf := make([]byte, 1024)
// Create a file with some contents.
fileName := path.Join(t.dir, "foo")
err = ioutil.WriteFile(fileName, []byte("Jello, "), 0600)
AssertEq(nil, err)
// Open the file in append mode.
f, err := os.OpenFile(fileName, os.O_RDWR|os.O_APPEND, 0600)
t.toClose = append(t.toClose, f)
AssertEq(nil, err)
// Seek to somewhere silly and then write.
off, err = f.Seek(2, 0)
AssertEq(nil, err)
AssertEq(2, off)
n, err = f.Write([]byte("world!"))
AssertEq(nil, err)
AssertEq(6, n)
// The offset should have been updated to point at the end of the file.
off, err = getFileOffset(f)
AssertEq(nil, err)
ExpectEq(13, off)
// A random write should still work, without updating the offset.
n, err = f.WriteAt([]byte("H"), 0)
AssertEq(nil, err)
AssertEq(1, n)
off, err = getFileOffset(f)
AssertEq(nil, err)
ExpectEq(13, off)
// Read back the contents of the file, which should be correct even though we
// seeked to a silly place before writing the world part.
//
// Linux's support for pwrite is buggy; the pwrite(2) man page says this:
//
// POSIX requires that opening a file with the O_APPEND flag should have
// no affect on the location at which pwrite() writes data. However, on
// Linux, if a file is opened with O_APPEND, pwrite() appends data to
// the end of the file, regardless of the value of offset.
//
// So we allow either the POSIX result or the Linux result.
n, err = f.ReadAt(buf, 0)
AssertEq(io.EOF, err)
if runtime.GOOS == "linux" {
ExpectEq("Jello, world!H", string(buf[:n]))
} else {
ExpectEq("Hello, world!", string(buf[:n]))
}
}
func (t *PosixTest) ReadsPastEndOfFile() {
var err error
var n int
buf := make([]byte, 1024)
// Create a file.
f, err := os.Create(path.Join(t.dir, "foo"))
t.toClose = append(t.toClose, f)
AssertEq(nil, err)
// Give it some contents.
n, err = f.Write([]byte("taco"))
AssertEq(nil, err)
AssertEq(4, n)
// Read a range overlapping EOF.
n, err = f.ReadAt(buf[:4], 2)
AssertEq(io.EOF, err)
ExpectEq(2, n)
ExpectEq("co", string(buf[:n]))
// Read a range starting at EOF.
n, err = f.ReadAt(buf[:4], 4)
AssertEq(io.EOF, err)
ExpectEq(0, n)
ExpectEq("", string(buf[:n]))
// Read a range starting past EOF.
n, err = f.ReadAt(buf[:4], 100)
AssertEq(io.EOF, err)
ExpectEq(0, n)
ExpectEq("", string(buf[:n]))
}
func (t *PosixTest) HardLinkDirectory() {
dirName := path.Join(t.dir, "dir")
// Create a directory.
err := os.Mkdir(dirName, 0700)
AssertEq(nil, err)
// Attempt to hard-link it to a new name.
err = os.Link(dirName, path.Join(t.dir, "other"))
AssertNe(nil, err)
ExpectThat(err, Error(HasSubstr("link")))
ExpectThat(err, Error(HasSubstr("not permitted")))
}
func (t *PosixTest) RmdirWhileOpenedForReading() {
var err error
// Create a directory.
err = os.Mkdir(path.Join(t.dir, "dir"), 0700)
AssertEq(nil, err)
// Open the directory for reading.
f, err := os.Open(path.Join(t.dir, "dir"))
defer func() {
if f != nil {
ExpectEq(nil, f.Close())
}
}()
AssertEq(nil, err)
// Remove the directory.
err = os.Remove(path.Join(t.dir, "dir"))
AssertEq(nil, err)
// Create a new directory, with the same name even, and add some contents
// within it.
err = os.MkdirAll(path.Join(t.dir, "dir/foo"), 0700)
AssertEq(nil, err)
err = os.MkdirAll(path.Join(t.dir, "dir/bar"), 0700)
AssertEq(nil, err)
err = os.MkdirAll(path.Join(t.dir, "dir/baz"), 0700)
AssertEq(nil, err)
// We should still be able to stat the open file handle.
fi, err := f.Stat()
ExpectEq("dir", fi.Name())
// Attempt to read from the directory. This shouldn't see any junk from the
// new directory. It should either succeed with an empty result or should
// return ENOENT.
names, err := f.Readdirnames(0)
if err != nil {
ExpectThat(err, Error(HasSubstr("no such file")))
} else {
ExpectThat(names, ElementsAre())
}
}