feat(io): add Node in-memory filesystem (port from Borg DataNode) (#343) (#352)

Co-authored-by: Claude <developers@lethean.io>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
Vi 2026-02-05 20:30:23 +00:00 committed by GitHub
parent e0cc9526ea
commit dd25cff835
2 changed files with 925 additions and 0 deletions

382
pkg/io/node/node.go Normal file
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package node
import (
"archive/tar"
"bytes"
"io"
"io/fs"
"os"
"path"
"sort"
"strings"
"time"
)
// Node is an in-memory filesystem that implements fs.FS, fs.StatFS,
// and fs.ReadFileFS. It stores files as byte slices keyed by their
// path, with directories being implicit based on path prefixes.
//
// Ported from github.com/Snider/Borg/pkg/datanode.
type Node struct {
files map[string]*nodeFile
}
// Compile-time interface checks.
var (
_ fs.FS = (*Node)(nil)
_ fs.StatFS = (*Node)(nil)
_ fs.ReadFileFS = (*Node)(nil)
)
// New creates a new, empty Node.
func New() *Node {
return &Node{files: make(map[string]*nodeFile)}
}
// FromTar creates a new Node from a tarball.
func FromTar(tarball []byte) (*Node, error) {
n := New()
tarReader := tar.NewReader(bytes.NewReader(tarball))
for {
header, err := tarReader.Next()
if err == io.EOF {
break
}
if err != nil {
return nil, err
}
if header.Typeflag == tar.TypeReg {
data, err := io.ReadAll(tarReader)
if err != nil {
return nil, err
}
n.AddData(header.Name, data)
}
}
return n, nil
}
// ToTar serializes the Node to a tarball.
func (n *Node) ToTar() ([]byte, error) {
buf := new(bytes.Buffer)
tw := tar.NewWriter(buf)
for _, file := range n.files {
hdr := &tar.Header{
Name: file.name,
Mode: 0600,
Size: int64(len(file.content)),
ModTime: file.modTime,
}
if err := tw.WriteHeader(hdr); err != nil {
return nil, err
}
if _, err := tw.Write(file.content); err != nil {
return nil, err
}
}
if err := tw.Close(); err != nil {
return nil, err
}
return buf.Bytes(), nil
}
// AddData adds a file to the Node. If a file with the same name
// already exists it is overwritten. Directory entries (names ending
// in "/") and empty names are silently ignored.
func (n *Node) AddData(name string, content []byte) {
name = strings.TrimPrefix(name, "/")
if name == "" {
return
}
// Directories are implicit, so we don't store them.
// A name ending in "/" is treated as a directory.
if strings.HasSuffix(name, "/") {
return
}
n.files[name] = &nodeFile{
name: name,
content: content,
modTime: time.Now(),
}
}
// Open opens a file from the Node, satisfying the fs.FS interface.
func (n *Node) Open(name string) (fs.File, error) {
name = strings.TrimPrefix(name, "/")
if file, ok := n.files[name]; ok {
return &nodeFileReader{file: file}, nil
}
// Check if it's a directory.
prefix := name + "/"
if name == "." || name == "" {
prefix = ""
}
for p := range n.files {
if strings.HasPrefix(p, prefix) {
return &dirFile{path: name, modTime: time.Now()}, nil
}
}
return nil, fs.ErrNotExist
}
// Stat returns the FileInfo for the named file, satisfying the
// fs.StatFS interface.
func (n *Node) Stat(name string) (fs.FileInfo, error) {
name = strings.TrimPrefix(name, "/")
if file, ok := n.files[name]; ok {
return file.Stat()
}
// Check if it's a directory.
prefix := name + "/"
if name == "." || name == "" {
prefix = ""
}
for p := range n.files {
if strings.HasPrefix(p, prefix) {
return &dirInfo{name: path.Base(name), modTime: time.Now()}, nil
}
}
return nil, fs.ErrNotExist
}
// ReadFile reads the named file and returns its contents, satisfying
// the fs.ReadFileFS interface.
func (n *Node) ReadFile(name string) ([]byte, error) {
name = strings.TrimPrefix(name, "/")
if file, ok := n.files[name]; ok {
// Return a copy so callers cannot mutate the internal state.
out := make([]byte, len(file.content))
copy(out, file.content)
return out, nil
}
return nil, fs.ErrNotExist
}
// ReadDir reads and returns all directory entries for the named directory.
func (n *Node) ReadDir(name string) ([]fs.DirEntry, error) {
name = strings.TrimPrefix(name, "/")
if name == "." {
name = ""
}
// Disallow reading a file as a directory.
if info, err := n.Stat(name); err == nil && !info.IsDir() {
return nil, &fs.PathError{Op: "readdir", Path: name, Err: fs.ErrInvalid}
}
entries := []fs.DirEntry{}
seen := make(map[string]bool)
prefix := ""
if name != "" {
prefix = name + "/"
}
for p := range n.files {
if !strings.HasPrefix(p, prefix) {
continue
}
relPath := strings.TrimPrefix(p, prefix)
firstComponent := strings.Split(relPath, "/")[0]
if seen[firstComponent] {
continue
}
seen[firstComponent] = true
if strings.Contains(relPath, "/") {
// It's a directory.
dir := &dirInfo{name: firstComponent, modTime: time.Now()}
entries = append(entries, fs.FileInfoToDirEntry(dir))
} else {
// It's a file.
file := n.files[p]
info, _ := file.Stat()
entries = append(entries, fs.FileInfoToDirEntry(info))
}
}
// Sort for stable order.
sort.Slice(entries, func(i, j int) bool {
return entries[i].Name() < entries[j].Name()
})
return entries, nil
}
// Exists returns true if the file or directory exists in the Node.
func (n *Node) Exists(name string, opts ...ExistsOptions) (bool, error) {
info, err := n.Stat(name)
if err != nil {
if err == fs.ErrNotExist || os.IsNotExist(err) {
return false, nil
}
return false, err
}
if len(opts) > 0 {
if opts[0].WantType == fs.ModeDir && !info.IsDir() {
return false, nil
}
if opts[0].WantType != fs.ModeDir && info.IsDir() {
return false, nil
}
}
return true, nil
}
// ExistsOptions allows customizing the Exists check.
type ExistsOptions struct {
WantType fs.FileMode
}
// WalkOptions allows customizing the Walk behavior.
type WalkOptions struct {
MaxDepth int
Filter func(path string, d fs.DirEntry) bool
SkipErrors bool
}
// Walk recursively descends the file tree rooted at root, calling fn
// for each file or directory in the tree.
func (n *Node) Walk(root string, fn fs.WalkDirFunc, opts ...WalkOptions) error {
var maxDepth int
var filter func(string, fs.DirEntry) bool
var skipErrors bool
if len(opts) > 0 {
maxDepth = opts[0].MaxDepth
filter = opts[0].Filter
skipErrors = opts[0].SkipErrors
}
return fs.WalkDir(n, root, func(p string, de fs.DirEntry, err error) error {
if err != nil {
if skipErrors {
return nil
}
return fn(p, de, err)
}
if filter != nil && !filter(p, de) {
if de.IsDir() {
return fs.SkipDir
}
return nil
}
// Process the entry first.
if err := fn(p, de, nil); err != nil {
return err
}
if maxDepth > 0 {
// Calculate depth relative to root.
cleanedPath := strings.TrimPrefix(p, root)
cleanedPath = strings.TrimPrefix(cleanedPath, "/")
currentDepth := 0
if p != root {
if cleanedPath == "" {
currentDepth = 0
} else {
currentDepth = strings.Count(cleanedPath, "/") + 1
}
}
if de.IsDir() && currentDepth >= maxDepth {
return fs.SkipDir
}
}
return nil
})
}
// CopyFile copies a file from the Node to the local filesystem.
func (n *Node) CopyFile(sourcePath string, target string, perm os.FileMode) error {
sourceFile, err := n.Open(sourcePath)
if err != nil {
return err
}
defer sourceFile.Close()
targetFile, err := os.OpenFile(target, os.O_CREATE|os.O_RDWR, perm)
if err != nil {
return err
}
defer targetFile.Close()
_, err = io.Copy(targetFile, sourceFile)
return err
}
// ---------------------------------------------------------------------------
// Internal types
// ---------------------------------------------------------------------------
// nodeFile represents a file stored in the Node.
type nodeFile struct {
name string
content []byte
modTime time.Time
}
func (f *nodeFile) Stat() (fs.FileInfo, error) { return &nodeFileInfo{file: f}, nil }
func (f *nodeFile) Read([]byte) (int, error) { return 0, io.EOF }
func (f *nodeFile) Close() error { return nil }
// nodeFileInfo implements fs.FileInfo for a nodeFile.
type nodeFileInfo struct{ file *nodeFile }
func (i *nodeFileInfo) Name() string { return path.Base(i.file.name) }
func (i *nodeFileInfo) Size() int64 { return int64(len(i.file.content)) }
func (i *nodeFileInfo) Mode() fs.FileMode { return 0444 }
func (i *nodeFileInfo) ModTime() time.Time { return i.file.modTime }
func (i *nodeFileInfo) IsDir() bool { return false }
func (i *nodeFileInfo) Sys() interface{} { return nil }
// nodeFileReader implements fs.File for reading a nodeFile.
type nodeFileReader struct {
file *nodeFile
reader *bytes.Reader
}
func (r *nodeFileReader) Stat() (fs.FileInfo, error) { return r.file.Stat() }
func (r *nodeFileReader) Read(p []byte) (int, error) {
if r.reader == nil {
r.reader = bytes.NewReader(r.file.content)
}
return r.reader.Read(p)
}
func (r *nodeFileReader) Close() error { return nil }
// dirInfo implements fs.FileInfo for an implicit directory.
type dirInfo struct {
name string
modTime time.Time
}
func (d *dirInfo) Name() string { return d.name }
func (d *dirInfo) Size() int64 { return 0 }
func (d *dirInfo) Mode() fs.FileMode { return fs.ModeDir | 0555 }
func (d *dirInfo) ModTime() time.Time { return d.modTime }
func (d *dirInfo) IsDir() bool { return true }
func (d *dirInfo) Sys() interface{} { return nil }
// dirFile implements fs.File for a directory.
type dirFile struct {
path string
modTime time.Time
}
func (d *dirFile) Stat() (fs.FileInfo, error) {
return &dirInfo{name: path.Base(d.path), modTime: d.modTime}, nil
}
func (d *dirFile) Read([]byte) (int, error) {
return 0, &fs.PathError{Op: "read", Path: d.path, Err: fs.ErrInvalid}
}
func (d *dirFile) Close() error { return nil }

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pkg/io/node/node_test.go Normal file
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package node
import (
"archive/tar"
"bytes"
"errors"
"io"
"io/fs"
"os"
"path/filepath"
"sort"
"strings"
"testing"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
)
// ---------------------------------------------------------------------------
// New
// ---------------------------------------------------------------------------
func TestNew_Good(t *testing.T) {
n := New()
require.NotNil(t, n, "New() must not return nil")
assert.NotNil(t, n.files, "New() must initialize the files map")
}
// ---------------------------------------------------------------------------
// AddData
// ---------------------------------------------------------------------------
func TestAddData_Good(t *testing.T) {
n := New()
n.AddData("foo.txt", []byte("foo"))
file, ok := n.files["foo.txt"]
require.True(t, ok, "file foo.txt should be present")
assert.Equal(t, []byte("foo"), file.content)
info, err := file.Stat()
require.NoError(t, err)
assert.Equal(t, "foo.txt", info.Name())
}
func TestAddData_Bad(t *testing.T) {
n := New()
// Empty name is silently ignored.
n.AddData("", []byte("data"))
assert.Empty(t, n.files, "empty name must not be stored")
// Directory entry (trailing slash) is silently ignored.
n.AddData("dir/", nil)
assert.Empty(t, n.files, "directory entry must not be stored")
}
func TestAddData_Ugly(t *testing.T) {
t.Run("Overwrite", func(t *testing.T) {
n := New()
n.AddData("foo.txt", []byte("foo"))
n.AddData("foo.txt", []byte("bar"))
file := n.files["foo.txt"]
assert.Equal(t, []byte("bar"), file.content, "second AddData should overwrite")
})
t.Run("LeadingSlash", func(t *testing.T) {
n := New()
n.AddData("/hello.txt", []byte("hi"))
_, ok := n.files["hello.txt"]
assert.True(t, ok, "leading slash should be trimmed")
})
}
// ---------------------------------------------------------------------------
// Open
// ---------------------------------------------------------------------------
func TestOpen_Good(t *testing.T) {
n := New()
n.AddData("foo.txt", []byte("foo"))
file, err := n.Open("foo.txt")
require.NoError(t, err)
defer file.Close()
buf := make([]byte, 10)
nr, err := file.Read(buf)
require.True(t, nr > 0 || err == io.EOF)
assert.Equal(t, "foo", string(buf[:nr]))
}
func TestOpen_Bad(t *testing.T) {
n := New()
_, err := n.Open("nonexistent.txt")
require.Error(t, err)
assert.ErrorIs(t, err, fs.ErrNotExist)
}
func TestOpen_Ugly(t *testing.T) {
n := New()
n.AddData("bar/baz.txt", []byte("baz"))
// Opening a directory should succeed.
file, err := n.Open("bar")
require.NoError(t, err)
defer file.Close()
// Reading from a directory should fail.
_, err = file.Read(make([]byte, 1))
require.Error(t, err)
var pathErr *fs.PathError
require.True(t, errors.As(err, &pathErr))
assert.Equal(t, fs.ErrInvalid, pathErr.Err)
}
// ---------------------------------------------------------------------------
// Stat
// ---------------------------------------------------------------------------
func TestStat_Good(t *testing.T) {
n := New()
n.AddData("foo.txt", []byte("foo"))
n.AddData("bar/baz.txt", []byte("baz"))
// File stat.
info, err := n.Stat("bar/baz.txt")
require.NoError(t, err)
assert.Equal(t, "baz.txt", info.Name())
assert.Equal(t, int64(3), info.Size())
assert.False(t, info.IsDir())
// Directory stat.
dirInfo, err := n.Stat("bar")
require.NoError(t, err)
assert.True(t, dirInfo.IsDir())
assert.Equal(t, "bar", dirInfo.Name())
}
func TestStat_Bad(t *testing.T) {
n := New()
_, err := n.Stat("nonexistent")
require.Error(t, err)
assert.ErrorIs(t, err, fs.ErrNotExist)
}
func TestStat_Ugly(t *testing.T) {
n := New()
n.AddData("foo.txt", []byte("foo"))
// Root directory.
info, err := n.Stat(".")
require.NoError(t, err)
assert.True(t, info.IsDir())
assert.Equal(t, ".", info.Name())
}
// ---------------------------------------------------------------------------
// ReadFile
// ---------------------------------------------------------------------------
func TestReadFile_Good(t *testing.T) {
n := New()
n.AddData("hello.txt", []byte("hello world"))
data, err := n.ReadFile("hello.txt")
require.NoError(t, err)
assert.Equal(t, []byte("hello world"), data)
}
func TestReadFile_Bad(t *testing.T) {
n := New()
_, err := n.ReadFile("missing.txt")
require.Error(t, err)
assert.ErrorIs(t, err, fs.ErrNotExist)
}
func TestReadFile_Ugly(t *testing.T) {
n := New()
n.AddData("data.bin", []byte("original"))
// Returned slice must be a copy — mutating it must not affect internal state.
data, err := n.ReadFile("data.bin")
require.NoError(t, err)
data[0] = 'X'
data2, err := n.ReadFile("data.bin")
require.NoError(t, err)
assert.Equal(t, []byte("original"), data2, "ReadFile must return an independent copy")
}
// ---------------------------------------------------------------------------
// ReadDir
// ---------------------------------------------------------------------------
func TestReadDir_Good(t *testing.T) {
n := New()
n.AddData("foo.txt", []byte("foo"))
n.AddData("bar/baz.txt", []byte("baz"))
n.AddData("bar/qux.txt", []byte("qux"))
// Root.
entries, err := n.ReadDir(".")
require.NoError(t, err)
assert.Equal(t, []string{"bar", "foo.txt"}, sortedNames(entries))
// Subdirectory.
barEntries, err := n.ReadDir("bar")
require.NoError(t, err)
assert.Equal(t, []string{"baz.txt", "qux.txt"}, sortedNames(barEntries))
}
func TestReadDir_Bad(t *testing.T) {
n := New()
n.AddData("foo.txt", []byte("foo"))
// Reading a file as a directory should fail.
_, err := n.ReadDir("foo.txt")
require.Error(t, err)
var pathErr *fs.PathError
require.True(t, errors.As(err, &pathErr))
assert.Equal(t, fs.ErrInvalid, pathErr.Err)
}
func TestReadDir_Ugly(t *testing.T) {
n := New()
n.AddData("bar/baz.txt", []byte("baz"))
n.AddData("empty_dir/", nil) // Ignored by AddData.
entries, err := n.ReadDir(".")
require.NoError(t, err)
assert.Equal(t, []string{"bar"}, sortedNames(entries))
}
// ---------------------------------------------------------------------------
// Exists
// ---------------------------------------------------------------------------
func TestExists_Good(t *testing.T) {
n := New()
n.AddData("foo.txt", []byte("foo"))
n.AddData("bar/baz.txt", []byte("baz"))
exists, err := n.Exists("foo.txt")
require.NoError(t, err)
assert.True(t, exists)
exists, err = n.Exists("bar")
require.NoError(t, err)
assert.True(t, exists)
}
func TestExists_Bad(t *testing.T) {
n := New()
exists, err := n.Exists("nonexistent")
require.NoError(t, err)
assert.False(t, exists)
}
func TestExists_Ugly(t *testing.T) {
n := New()
n.AddData("dummy.txt", []byte("dummy"))
exists, err := n.Exists(".")
require.NoError(t, err)
assert.True(t, exists, "root '.' must exist")
exists, err = n.Exists("")
require.NoError(t, err)
assert.True(t, exists, "empty path (root) must exist")
}
// ---------------------------------------------------------------------------
// Walk
// ---------------------------------------------------------------------------
func TestWalk_Good(t *testing.T) {
n := New()
n.AddData("foo.txt", []byte("foo"))
n.AddData("bar/baz.txt", []byte("baz"))
n.AddData("bar/qux.txt", []byte("qux"))
var paths []string
err := n.Walk(".", func(p string, d fs.DirEntry, err error) error {
paths = append(paths, p)
return nil
})
require.NoError(t, err)
sort.Strings(paths)
assert.Equal(t, []string{".", "bar", "bar/baz.txt", "bar/qux.txt", "foo.txt"}, paths)
}
func TestWalk_Bad(t *testing.T) {
n := New()
var called bool
err := n.Walk("nonexistent", func(p string, d fs.DirEntry, err error) error {
called = true
assert.Error(t, err)
assert.ErrorIs(t, err, fs.ErrNotExist)
return err
})
assert.True(t, called, "walk function must be called for nonexistent root")
assert.ErrorIs(t, err, fs.ErrNotExist)
}
func TestWalk_Ugly(t *testing.T) {
n := New()
n.AddData("a/b.txt", []byte("b"))
n.AddData("a/c.txt", []byte("c"))
// Stop walk early with a custom error.
walkErr := errors.New("stop walking")
var paths []string
err := n.Walk(".", func(p string, d fs.DirEntry, err error) error {
if p == "a/b.txt" {
return walkErr
}
paths = append(paths, p)
return nil
})
assert.Equal(t, walkErr, err, "Walk must propagate the callback error")
}
func TestWalk_Options(t *testing.T) {
n := New()
n.AddData("root.txt", []byte("root"))
n.AddData("a/a1.txt", []byte("a1"))
n.AddData("a/b/b1.txt", []byte("b1"))
n.AddData("c/c1.txt", []byte("c1"))
t.Run("MaxDepth", func(t *testing.T) {
var paths []string
err := n.Walk(".", func(p string, d fs.DirEntry, err error) error {
paths = append(paths, p)
return nil
}, WalkOptions{MaxDepth: 1})
require.NoError(t, err)
sort.Strings(paths)
assert.Equal(t, []string{".", "a", "c", "root.txt"}, paths)
})
t.Run("Filter", func(t *testing.T) {
var paths []string
err := n.Walk(".", func(p string, d fs.DirEntry, err error) error {
paths = append(paths, p)
return nil
}, WalkOptions{Filter: func(p string, d fs.DirEntry) bool {
return !strings.HasPrefix(p, "a")
}})
require.NoError(t, err)
sort.Strings(paths)
assert.Equal(t, []string{".", "c", "c/c1.txt", "root.txt"}, paths)
})
t.Run("SkipErrors", func(t *testing.T) {
var called bool
err := n.Walk("nonexistent", func(p string, d fs.DirEntry, err error) error {
called = true
return err
}, WalkOptions{SkipErrors: true})
assert.NoError(t, err, "SkipErrors should suppress the error")
assert.False(t, called, "callback should not be called when error is skipped")
})
}
// ---------------------------------------------------------------------------
// CopyFile
// ---------------------------------------------------------------------------
func TestCopyFile_Good(t *testing.T) {
n := New()
n.AddData("foo.txt", []byte("foo"))
tmpfile := filepath.Join(t.TempDir(), "test.txt")
err := n.CopyFile("foo.txt", tmpfile, 0644)
require.NoError(t, err)
content, err := os.ReadFile(tmpfile)
require.NoError(t, err)
assert.Equal(t, "foo", string(content))
}
func TestCopyFile_Bad(t *testing.T) {
n := New()
tmpfile := filepath.Join(t.TempDir(), "test.txt")
// Source does not exist.
err := n.CopyFile("nonexistent.txt", tmpfile, 0644)
assert.Error(t, err)
// Destination not writable.
n.AddData("foo.txt", []byte("foo"))
err = n.CopyFile("foo.txt", "/nonexistent_dir/test.txt", 0644)
assert.Error(t, err)
}
func TestCopyFile_Ugly(t *testing.T) {
n := New()
n.AddData("bar/baz.txt", []byte("baz"))
tmpfile := filepath.Join(t.TempDir(), "test.txt")
// Attempting to copy a directory should fail.
err := n.CopyFile("bar", tmpfile, 0644)
assert.Error(t, err)
}
// ---------------------------------------------------------------------------
// ToTar / FromTar
// ---------------------------------------------------------------------------
func TestToTar_Good(t *testing.T) {
n := New()
n.AddData("foo.txt", []byte("foo"))
n.AddData("bar/baz.txt", []byte("baz"))
tarball, err := n.ToTar()
require.NoError(t, err)
require.NotEmpty(t, tarball)
// Verify tar content.
tr := tar.NewReader(bytes.NewReader(tarball))
files := make(map[string]string)
for {
header, err := tr.Next()
if err == io.EOF {
break
}
require.NoError(t, err)
content, err := io.ReadAll(tr)
require.NoError(t, err)
files[header.Name] = string(content)
}
assert.Equal(t, "foo", files["foo.txt"])
assert.Equal(t, "baz", files["bar/baz.txt"])
}
func TestFromTar_Good(t *testing.T) {
buf := new(bytes.Buffer)
tw := tar.NewWriter(buf)
for _, f := range []struct{ Name, Body string }{
{"foo.txt", "foo"},
{"bar/baz.txt", "baz"},
} {
hdr := &tar.Header{
Name: f.Name,
Mode: 0600,
Size: int64(len(f.Body)),
Typeflag: tar.TypeReg,
}
require.NoError(t, tw.WriteHeader(hdr))
_, err := tw.Write([]byte(f.Body))
require.NoError(t, err)
}
require.NoError(t, tw.Close())
n, err := FromTar(buf.Bytes())
require.NoError(t, err)
exists, _ := n.Exists("foo.txt")
assert.True(t, exists, "foo.txt should exist")
exists, _ = n.Exists("bar/baz.txt")
assert.True(t, exists, "bar/baz.txt should exist")
}
func TestFromTar_Bad(t *testing.T) {
// Truncated data that cannot be a valid tar.
truncated := make([]byte, 100)
_, err := FromTar(truncated)
assert.Error(t, err, "truncated data should produce an error")
}
func TestTarRoundTrip_Good(t *testing.T) {
n1 := New()
n1.AddData("a.txt", []byte("alpha"))
n1.AddData("b/c.txt", []byte("charlie"))
tarball, err := n1.ToTar()
require.NoError(t, err)
n2, err := FromTar(tarball)
require.NoError(t, err)
// Verify n2 matches n1.
data, err := n2.ReadFile("a.txt")
require.NoError(t, err)
assert.Equal(t, []byte("alpha"), data)
data, err = n2.ReadFile("b/c.txt")
require.NoError(t, err)
assert.Equal(t, []byte("charlie"), data)
}
// ---------------------------------------------------------------------------
// fs.FS interface compliance
// ---------------------------------------------------------------------------
func TestFSInterface_Good(t *testing.T) {
n := New()
n.AddData("hello.txt", []byte("world"))
// fs.FS
var fsys fs.FS = n
file, err := fsys.Open("hello.txt")
require.NoError(t, err)
defer file.Close()
// fs.StatFS
var statFS fs.StatFS = n
info, err := statFS.Stat("hello.txt")
require.NoError(t, err)
assert.Equal(t, "hello.txt", info.Name())
assert.Equal(t, int64(5), info.Size())
// fs.ReadFileFS
var readFS fs.ReadFileFS = n
data, err := readFS.ReadFile("hello.txt")
require.NoError(t, err)
assert.Equal(t, []byte("world"), data)
}
// ---------------------------------------------------------------------------
// Helpers
// ---------------------------------------------------------------------------
func sortedNames(entries []fs.DirEntry) []string {
var names []string
for _, e := range entries {
names = append(names, e.Name())
}
sort.Strings(names)
return names
}