atomic_writer_test.go

// +build linux

/*
Copyright 2016 The Kubernetes Authors.

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.
*/

package util

import (
	"encoding/base64"
	"io/ioutil"
	"os"
	"path"
	"path/filepath"
	"reflect"
	"strings"
	"testing"

	"k8s.io/kubernetes/pkg/util/sets"
	utiltesting "k8s.io/kubernetes/pkg/util/testing"
)

func TestNewAtomicWriter(t *testing.T) {
	targetDir, err := utiltesting.MkTmpdir("atomic-write")
	if err != nil {
		t.Fatalf("unexpected error creating tmp dir: %v", err)
	}

	_, err = NewAtomicWriter(targetDir, "-test-")
	if err != nil {
		t.Fatalf("unexpected error creating writer for existing target dir: %v", err)
	}

	nonExistentDir, err := utiltesting.MkTmpdir("atomic-write")
	if err != nil {
		t.Fatalf("unexpected error creating tmp dir: %v", err)
	}
	err = os.Remove(nonExistentDir)
	if err != nil {
		t.Fatalf("unexpected error ensuring dir %v does not exist: %v", nonExistentDir, err)
	}

	_, err = NewAtomicWriter(nonExistentDir, "-test-")
	if err == nil {
		t.Fatalf("unexpected success creating writer for nonexistent target dir: %v", err)
	}
}

func TestValidatePath(t *testing.T) {
	maxPath := strings.Repeat("a", maxPathLength+1)
	maxFile := strings.Repeat("a", maxFileNameLength+1)

	cases := []struct {
		name  string
		path  string
		valid bool
	}{
		{
			name:  "valid 1",
			path:  "i/am/well/behaved.txt",
			valid: true,
		},
		{
			name:  "valid 2",
			path:  "keepyourheaddownandfollowtherules.txt",
			valid: true,
		},
		{
			name:  "max path length",
			path:  maxPath,
			valid: false,
		},
		{
			name:  "max file length",
			path:  maxFile,
			valid: false,
		},
		{
			name:  "absolute failure",
			path:  "/dev/null",
			valid: false,
		},
		{
			name:  "reserved path",
			path:  "..sneaky.txt",
			valid: false,
		},
		{
			name:  "contains doubledot 1",
			path:  "hello/there/../../../../../../etc/passwd",
			valid: false,
		},
		{
			name:  "contains doubledot 2",
			path:  "hello/../etc/somethingbad",
			valid: false,
		},
		{
			name:  "empty",
			path:  "",
			valid: false,
		},
	}

	for _, tc := range cases {
		err := validatePath(tc.path)
		if tc.valid && err != nil {
			t.Errorf("%v: unexpected failure: %v", tc.name, err)
			continue
		}

		if !tc.valid && err == nil {
			t.Errorf("%v: unexpected success", tc.name)
		}
	}
}

func TestPathsToRemove(t *testing.T) {
	cases := []struct {
		name     string
		payload1 map[string]FileProjection
		payload2 map[string]FileProjection
		expected sets.String
	}{
		{
			name: "simple",
			payload1: map[string]FileProjection{
				"foo.txt": {Mode: 0644, Data: []byte("foo")},
				"bar.txt": {Mode: 0644, Data: []byte("bar")},
			},
			payload2: map[string]FileProjection{
				"foo.txt": {Mode: 0644, Data: []byte("foo")},
			},
			expected: sets.NewString("bar.txt"),
		},
		{
			name: "simple 2",
			payload1: map[string]FileProjection{
				"foo.txt":     {Mode: 0644, Data: []byte("foo")},
				"zip/bar.txt": {Mode: 0644, Data: []byte("zip/b}ar")},
			},
			payload2: map[string]FileProjection{
				"foo.txt": {Mode: 0644, Data: []byte("foo")},
			},
			expected: sets.NewString("zip/bar.txt", "zip"),
		},
		{
			name: "subdirs 1",
			payload1: map[string]FileProjection{
				"foo.txt":         {Mode: 0644, Data: []byte("foo")},
				"zip/zap/bar.txt": {Mode: 0644, Data: []byte("zip/bar")},
			},
			payload2: map[string]FileProjection{
				"foo.txt": {Mode: 0644, Data: []byte("foo")},
			},
			expected: sets.NewString("zip/zap/bar.txt", "zip", "zip/zap"),
		},
		{
			name: "subdirs 2",
			payload1: map[string]FileProjection{
				"foo.txt":             {Mode: 0644, Data: []byte("foo")},
				"zip/1/2/3/4/bar.txt": {Mode: 0644, Data: []byte("zip/b}ar")},
			},
			payload2: map[string]FileProjection{
				"foo.txt": {Mode: 0644, Data: []byte("foo")},
			},
			expected: sets.NewString("zip/1/2/3/4/bar.txt", "zip", "zip/1", "zip/1/2", "zip/1/2/3", "zip/1/2/3/4"),
		},
		{
			name: "subdirs 3",
			payload1: map[string]FileProjection{
				"foo.txt":             {Mode: 0644, Data: []byte("foo")},
				"zip/1/2/3/4/bar.txt": {Mode: 0644, Data: []byte("zip/b}ar")},
				"zap/a/b/c/bar.txt":   {Mode: 0644, Data: []byte("zap/bar")},
			},
			payload2: map[string]FileProjection{
				"foo.txt": {Mode: 0644, Data: []byte("foo")},
			},
			expected: sets.NewString("zip/1/2/3/4/bar.txt", "zip", "zip/1", "zip/1/2", "zip/1/2/3", "zip/1/2/3/4", "zap", "zap/a", "zap/a/b", "zap/a/b/c", "zap/a/b/c/bar.txt"),
		},
		{
			name: "subdirs 4",
			payload1: map[string]FileProjection{
				"foo.txt":             {Mode: 0644, Data: []byte("foo")},
				"zap/1/2/3/4/bar.txt": {Mode: 0644, Data: []byte("zip/bar")},
				"zap/1/2/c/bar.txt":   {Mode: 0644, Data: []byte("zap/bar")},
				"zap/1/2/magic.txt":   {Mode: 0644, Data: []byte("indigo")},
			},
			payload2: map[string]FileProjection{
				"foo.txt":           {Mode: 0644, Data: []byte("foo")},
				"zap/1/2/magic.txt": {Mode: 0644, Data: []byte("indigo")},
			},
			expected: sets.NewString("zap/1/2/3/4/bar.txt", "zap/1/2/3", "zap/1/2/3/4", "zap/1/2/3/4/bar.txt", "zap/1/2/c", "zap/1/2/c/bar.txt"),
		},
		{
			name: "subdirs 5",
			payload1: map[string]FileProjection{
				"foo.txt":             {Mode: 0644, Data: []byte("foo")},
				"zap/1/2/3/4/bar.txt": {Mode: 0644, Data: []byte("zip/bar")},
				"zap/1/2/c/bar.txt":   {Mode: 0644, Data: []byte("zap/bar")},
			},
			payload2: map[string]FileProjection{
				"foo.txt":           {Mode: 0644, Data: []byte("foo")},
				"zap/1/2/magic.txt": {Mode: 0644, Data: []byte("indigo")},
			},
			expected: sets.NewString("zap/1/2/3/4/bar.txt", "zap/1/2/3", "zap/1/2/3/4", "zap/1/2/3/4/bar.txt", "zap/1/2/c", "zap/1/2/c/bar.txt"),
		},
	}

	for _, tc := range cases {
		targetDir, err := utiltesting.MkTmpdir("atomic-write")
		if err != nil {
			t.Errorf("%v: unexpected error creating tmp dir: %v", tc.name, err)
			continue
		}

		writer := &AtomicWriter{targetDir: targetDir, logContext: "-test-"}
		err = writer.Write(tc.payload1)
		if err != nil {
			t.Errorf("%v: unexpected error writing: %v", tc.name, err)
			continue
		}

		actual, err := writer.pathsToRemove(tc.payload2)
		if err != nil {
			t.Errorf("%v: unexpected error determining paths to remove: %v", tc.name, err)
			continue
		}

		if e, a := tc.expected, actual; !e.Equal(a) {
			t.Errorf("%v: unexpected paths to remove:\nexpected: %v\n     got: %v", tc.name, e, a)
		}
	}
}

func TestWriteOnce(t *testing.T) {
	// $1 if you can tell me what this binary is
	encodedMysteryBinary := `f0VMRgIBAQAAAAAAAAAAAAIAPgABAAAAeABAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAEAAOAAB
AAAAAAAAAAEAAAAFAAAAAAAAAAAAAAAAAEAAAAAAAAAAQAAAAAAAfQAAAAAAAAB9AAAAAAAAAAAA
IAAAAAAAsDyZDwU=`

	mysteryBinaryBytes := make([]byte, base64.StdEncoding.DecodedLen(len(encodedMysteryBinary)))
	numBytes, err := base64.StdEncoding.Decode(mysteryBinaryBytes, []byte(encodedMysteryBinary))
	if err != nil {
		t.Fatalf("Unexpected error decoding binary payload: %v", err)
	}

	if numBytes != 125 {
		t.Fatalf("Unexpected decoded binary size: expected 125, got %v", numBytes)
	}

	cases := []struct {
		name    string
		payload map[string]FileProjection
		success bool
	}{
		{
			name: "invalid payload 1",
			payload: map[string]FileProjection{
				"foo":        {Mode: 0644, Data: []byte("foo")},
				"..bar":      {Mode: 0644, Data: []byte("bar")},
				"binary.bin": {Mode: 0644, Data: mysteryBinaryBytes},
			},
			success: false,
		},
		{
			name: "invalid payload 2",
			payload: map[string]FileProjection{
				"foo/../bar": {Mode: 0644, Data: []byte("foo")},
			},
			success: false,
		},
		{
			name: "basic 1",
			payload: map[string]FileProjection{
				"foo": {Mode: 0644, Data: []byte("foo")},
				"bar": {Mode: 0644, Data: []byte("bar")},
			},
			success: true,
		},
		{
			name: "basic 2",
			payload: map[string]FileProjection{
				"binary.bin":  {Mode: 0644, Data: mysteryBinaryBytes},
				".binary.bin": {Mode: 0644, Data: mysteryBinaryBytes},
			},
			success: true,
		},
		{
			name: "basic mode 1",
			payload: map[string]FileProjection{
				"foo": {Mode: 0777, Data: []byte("foo")},
				"bar": {Mode: 0400, Data: []byte("bar")},
			},
			success: true,
		},
		{
			name: "dotfiles",
			payload: map[string]FileProjection{
				"foo":           {Mode: 0644, Data: []byte("foo")},
				"bar":           {Mode: 0644, Data: []byte("bar")},
				".dotfile":      {Mode: 0644, Data: []byte("dotfile")},
				".dotfile.file": {Mode: 0644, Data: []byte("dotfile.file")},
			},
			success: true,
		},
		{
			name: "dotfiles mode",
			payload: map[string]FileProjection{
				"foo":           {Mode: 0407, Data: []byte("foo")},
				"bar":           {Mode: 0440, Data: []byte("bar")},
				".dotfile":      {Mode: 0777, Data: []byte("dotfile")},
				".dotfile.file": {Mode: 0666, Data: []byte("dotfile.file")},
			},
			success: true,
		},
		{
			name: "subdirectories 1",
			payload: map[string]FileProjection{
				"foo/bar.txt": {Mode: 0644, Data: []byte("foo/bar")},
				"bar/zab.txt": {Mode: 0644, Data: []byte("bar/zab.txt")},
			},
			success: true,
		},
		{
			name: "subdirectories mode 1",
			payload: map[string]FileProjection{
				"foo/bar.txt": {Mode: 0400, Data: []byte("foo/bar")},
				"bar/zab.txt": {Mode: 0644, Data: []byte("bar/zab.txt")},
			},
			success: true,
		},
		{
			name: "subdirectories 2",
			payload: map[string]FileProjection{
				"foo//bar.txt":      {Mode: 0644, Data: []byte("foo//bar")},
				"bar///bar/zab.txt": {Mode: 0644, Data: []byte("bar/../bar/zab.txt")},
			},
			success: true,
		},
		{
			name: "subdirectories 3",
			payload: map[string]FileProjection{
				"foo/bar.txt":      {Mode: 0644, Data: []byte("foo/bar")},
				"bar/zab.txt":      {Mode: 0644, Data: []byte("bar/zab.txt")},
				"foo/blaz/bar.txt": {Mode: 0644, Data: []byte("foo/blaz/bar")},
				"bar/zib/zab.txt":  {Mode: 0644, Data: []byte("bar/zib/zab.txt")},
			},
			success: true,
		},
		{
			name: "kitchen sink",
			payload: map[string]FileProjection{
				"foo.log":                           {Mode: 0644, Data: []byte("foo")},
				"bar.zap":                           {Mode: 0644, Data: []byte("bar")},
				".dotfile":                          {Mode: 0644, Data: []byte("dotfile")},
				"foo/bar.txt":                       {Mode: 0644, Data: []byte("foo/bar")},
				"bar/zab.txt":                       {Mode: 0644, Data: []byte("bar/zab.txt")},
				"foo/blaz/bar.txt":                  {Mode: 0644, Data: []byte("foo/blaz/bar")},
				"bar/zib/zab.txt":                   {Mode: 0400, Data: []byte("bar/zib/zab.txt")},
				"1/2/3/4/5/6/7/8/9/10/.dotfile.lib": {Mode: 0777, Data: []byte("1-2-3-dotfile")},
			},
			success: true,
		},
	}

	for _, tc := range cases {
		targetDir, err := utiltesting.MkTmpdir("atomic-write")
		if err != nil {
			t.Errorf("%v: unexpected error creating tmp dir: %v", tc.name, err)
			continue
		}

		writer := &AtomicWriter{targetDir: targetDir, logContext: "-test-"}
		err = writer.Write(tc.payload)
		if err != nil && tc.success {
			t.Errorf("%v: unexpected error writing payload: %v", tc.name, err)
			continue
		} else if err == nil && !tc.success {
			t.Errorf("%v: unexpected success", tc.name)
			continue
		} else if err != nil {
			continue
		}

		checkVolumeContents(targetDir, tc.name, tc.payload, t)
	}
}

func TestUpdate(t *testing.T) {
	cases := []struct {
		name        string
		first       map[string]FileProjection
		next        map[string]FileProjection
		shouldWrite bool
	}{
		{
			name: "update",
			first: map[string]FileProjection{
				"foo": {Mode: 0644, Data: []byte("foo")},
				"bar": {Mode: 0644, Data: []byte("bar")},
			},
			next: map[string]FileProjection{
				"foo": {Mode: 0644, Data: []byte("foo2")},
				"bar": {Mode: 0640, Data: []byte("bar2")},
			},
			shouldWrite: true,
		},
		{
			name: "no update",
			first: map[string]FileProjection{
				"foo": {Mode: 0644, Data: []byte("foo")},
				"bar": {Mode: 0644, Data: []byte("bar")},
			},
			next: map[string]FileProjection{
				"foo": {Mode: 0644, Data: []byte("foo")},
				"bar": {Mode: 0644, Data: []byte("bar")},
			},
			shouldWrite: false,
		},
		{
			name: "no update 2",
			first: map[string]FileProjection{
				"foo/bar.txt": {Mode: 0644, Data: []byte("foo")},
				"bar/zab.txt": {Mode: 0644, Data: []byte("bar")},
			},
			next: map[string]FileProjection{
				"foo/bar.txt": {Mode: 0644, Data: []byte("foo")},
				"bar/zab.txt": {Mode: 0644, Data: []byte("bar")},
			},
			shouldWrite: false,
		},
		{
			name: "add 1",
			first: map[string]FileProjection{
				"foo/bar.txt": {Mode: 0644, Data: []byte("foo")},
				"bar/zab.txt": {Mode: 0644, Data: []byte("bar")},
			},
			next: map[string]FileProjection{
				"foo/bar.txt": {Mode: 0644, Data: []byte("foo")},
				"bar/zab.txt": {Mode: 0644, Data: []byte("bar")},
				"blu/zip.txt": {Mode: 0644, Data: []byte("zip")},
			},
			shouldWrite: true,
		},
		{
			name: "add 2",
			first: map[string]FileProjection{
				"foo/bar.txt": {Mode: 0644, Data: []byte("foo")},
				"bar/zab.txt": {Mode: 0644, Data: []byte("bar")},
			},
			next: map[string]FileProjection{
				"foo/bar.txt":             {Mode: 0644, Data: []byte("foo")},
				"bar/zab.txt":             {Mode: 0644, Data: []byte("bar")},
				"blu/two/2/3/4/5/zip.txt": {Mode: 0644, Data: []byte("zip")},
			},
			shouldWrite: true,
		},
		{
			name: "add 3",
			first: map[string]FileProjection{
				"foo/bar.txt": {Mode: 0644, Data: []byte("foo")},
				"bar/zab.txt": {Mode: 0644, Data: []byte("bar")},
			},
			next: map[string]FileProjection{
				"foo/bar.txt":         {Mode: 0644, Data: []byte("foo")},
				"bar/zab.txt":         {Mode: 0644, Data: []byte("bar")},
				"bar/2/3/4/5/zip.txt": {Mode: 0644, Data: []byte("zip")},
			},
			shouldWrite: true,
		},
		{
			name: "delete 1",
			first: map[string]FileProjection{
				"foo/bar.txt": {Mode: 0644, Data: []byte("foo")},
				"bar/zab.txt": {Mode: 0644, Data: []byte("bar")},
			},
			next: map[string]FileProjection{
				"foo/bar.txt": {Mode: 0644, Data: []byte("foo")},
			},
			shouldWrite: true,
		},
		{
			name: "delete 2",
			first: map[string]FileProjection{
				"foo/bar.txt":       {Mode: 0644, Data: []byte("foo")},
				"bar/1/2/3/zab.txt": {Mode: 0644, Data: []byte("bar")},
			},
			next: map[string]FileProjection{
				"foo/bar.txt": {Mode: 0644, Data: []byte("foo")},
			},
			shouldWrite: true,
		},
		{
			name: "delete 3",
			first: map[string]FileProjection{
				"foo/bar.txt":       {Mode: 0644, Data: []byte("foo")},
				"bar/1/2/sip.txt":   {Mode: 0644, Data: []byte("sip")},
				"bar/1/2/3/zab.txt": {Mode: 0644, Data: []byte("bar")},
			},
			next: map[string]FileProjection{
				"foo/bar.txt":     {Mode: 0644, Data: []byte("foo")},
				"bar/1/2/sip.txt": {Mode: 0644, Data: []byte("sip")},
			},
			shouldWrite: true,
		},
		{
			name: "delete 4",
			first: map[string]FileProjection{
				"foo/bar.txt":            {Mode: 0644, Data: []byte("foo")},
				"bar/1/2/sip.txt":        {Mode: 0644, Data: []byte("sip")},
				"bar/1/2/3/4/5/6zab.txt": {Mode: 0644, Data: []byte("bar")},
			},
			next: map[string]FileProjection{
				"foo/bar.txt":     {Mode: 0644, Data: []byte("foo")},
				"bar/1/2/sip.txt": {Mode: 0644, Data: []byte("sip")},
			},
			shouldWrite: true,
		},
		{
			name: "delete all",
			first: map[string]FileProjection{
				"foo/bar.txt":            {Mode: 0644, Data: []byte("foo")},
				"bar/1/2/sip.txt":        {Mode: 0644, Data: []byte("sip")},
				"bar/1/2/3/4/5/6zab.txt": {Mode: 0644, Data: []byte("bar")},
			},
			next:        map[string]FileProjection{},
			shouldWrite: true,
		},
		{
			name: "add and delete 1",
			first: map[string]FileProjection{
				"foo/bar.txt": {Mode: 0644, Data: []byte("foo")},
			},
			next: map[string]FileProjection{
				"bar/baz.txt": {Mode: 0644, Data: []byte("baz")},
			},
			shouldWrite: true,
		},
	}

	for _, tc := range cases {
		targetDir, err := utiltesting.MkTmpdir("atomic-write")
		if err != nil {
			t.Errorf("%v: unexpected error creating tmp dir: %v", tc.name, err)
			continue
		}

		writer := &AtomicWriter{targetDir: targetDir, logContext: "-test-"}

		err = writer.Write(tc.first)
		if err != nil {
			t.Errorf("%v: unexpected error writing: %v", tc.name, err)
			continue
		}

		checkVolumeContents(targetDir, tc.name, tc.first, t)
		if !tc.shouldWrite {
			continue
		}

		err = writer.Write(tc.next)
		if err != nil {
			if tc.shouldWrite {
				t.Errorf("%v: unexpected error writing: %v", tc.name, err)
				continue
			}
		} else if !tc.shouldWrite {
			t.Errorf("%v: unexpected success", tc.name)
			continue
		}

		checkVolumeContents(targetDir, tc.name, tc.next, t)
	}
}

func TestMultipleUpdates(t *testing.T) {
	cases := []struct {
		name     string
		payloads []map[string]FileProjection
	}{
		{
			name: "update 1",
			payloads: []map[string]FileProjection{
				{
					"foo": {Mode: 0644, Data: []byte("foo")},
					"bar": {Mode: 0644, Data: []byte("bar")},
				},
				{
					"foo": {Mode: 0400, Data: []byte("foo2")},
					"bar": {Mode: 0400, Data: []byte("bar2")},
				},
				{
					"foo": {Mode: 0600, Data: []byte("foo3")},
					"bar": {Mode: 0600, Data: []byte("bar3")},
				},
			},
		},
		{
			name: "update 2",
			payloads: []map[string]FileProjection{
				{
					"foo/bar.txt": {Mode: 0644, Data: []byte("foo/bar")},
					"bar/zab.txt": {Mode: 0644, Data: []byte("bar/zab.txt")},
				},
				{
					"foo/bar.txt": {Mode: 0644, Data: []byte("foo/bar2")},
					"bar/zab.txt": {Mode: 0400, Data: []byte("bar/zab.txt2")},
				},
			},
		},
		{
			name: "clear sentinel",
			payloads: []map[string]FileProjection{
				{
					"foo": {Mode: 0644, Data: []byte("foo")},
					"bar": {Mode: 0644, Data: []byte("bar")},
				},
				{
					"foo": {Mode: 0644, Data: []byte("foo2")},
					"bar": {Mode: 0644, Data: []byte("bar2")},
				},
				{
					"foo": {Mode: 0644, Data: []byte("foo3")},
					"bar": {Mode: 0644, Data: []byte("bar3")},
				},
				{
					"foo": {Mode: 0644, Data: []byte("foo4")},
					"bar": {Mode: 0644, Data: []byte("bar4")},
				},
			},
		},
		{
			name: "subdirectories 2",
			payloads: []map[string]FileProjection{
				{
					"foo/bar.txt":      {Mode: 0644, Data: []byte("foo/bar")},
					"bar/zab.txt":      {Mode: 0644, Data: []byte("bar/zab.txt")},
					"foo/blaz/bar.txt": {Mode: 0644, Data: []byte("foo/blaz/bar")},
					"bar/zib/zab.txt":  {Mode: 0644, Data: []byte("bar/zib/zab.txt")},
				},
				{
					"foo/bar.txt":      {Mode: 0644, Data: []byte("foo/bar2")},
					"bar/zab.txt":      {Mode: 0644, Data: []byte("bar/zab.txt2")},
					"foo/blaz/bar.txt": {Mode: 0644, Data: []byte("foo/blaz/bar2")},
					"bar/zib/zab.txt":  {Mode: 0644, Data: []byte("bar/zib/zab.txt2")},
				},
			},
		},
		{
			name: "add 1",
			payloads: []map[string]FileProjection{
				{
					"foo/bar.txt":            {Mode: 0644, Data: []byte("foo/bar")},
					"bar//zab.txt":           {Mode: 0644, Data: []byte("bar/zab.txt")},
					"foo/blaz/bar.txt":       {Mode: 0644, Data: []byte("foo/blaz/bar")},
					"bar/zib////zib/zab.txt": {Mode: 0644, Data: []byte("bar/zib/zab.txt")},
				},
				{
					"foo/bar.txt":      {Mode: 0644, Data: []byte("foo/bar2")},
					"bar/zab.txt":      {Mode: 0644, Data: []byte("bar/zab.txt2")},
					"foo/blaz/bar.txt": {Mode: 0644, Data: []byte("foo/blaz/bar2")},
					"bar/zib/zab.txt":  {Mode: 0644, Data: []byte("bar/zib/zab.txt2")},
					"add/new/keys.txt": {Mode: 0644, Data: []byte("addNewKeys")},
				},
			},
		},
		{
			name: "add 2",
			payloads: []map[string]FileProjection{
				{
					"foo/bar.txt":      {Mode: 0644, Data: []byte("foo/bar2")},
					"bar/zab.txt":      {Mode: 0644, Data: []byte("bar/zab.txt2")},
					"foo/blaz/bar.txt": {Mode: 0644, Data: []byte("foo/blaz/bar2")},
					"bar/zib/zab.txt":  {Mode: 0644, Data: []byte("bar/zib/zab.txt2")},
					"add/new/keys.txt": {Mode: 0644, Data: []byte("addNewKeys")},
				},
				{
					"foo/bar.txt":       {Mode: 0644, Data: []byte("foo/bar2")},
					"bar/zab.txt":       {Mode: 0644, Data: []byte("bar/zab.txt2")},
					"foo/blaz/bar.txt":  {Mode: 0644, Data: []byte("foo/blaz/bar2")},
					"bar/zib/zab.txt":   {Mode: 0644, Data: []byte("bar/zib/zab.txt2")},
					"add/new/keys.txt":  {Mode: 0644, Data: []byte("addNewKeys")},
					"add/new/keys2.txt": {Mode: 0644, Data: []byte("addNewKeys2")},
					"add/new/keys3.txt": {Mode: 0644, Data: []byte("addNewKeys3")},
				},
			},
		},
		{
			name: "remove 1",
			payloads: []map[string]FileProjection{
				{
					"foo/bar.txt":         {Mode: 0644, Data: []byte("foo/bar")},
					"bar//zab.txt":        {Mode: 0644, Data: []byte("bar/zab.txt")},
					"foo/blaz/bar.txt":    {Mode: 0644, Data: []byte("foo/blaz/bar")},
					"zip/zap/zup/fop.txt": {Mode: 0644, Data: []byte("zip/zap/zup/fop.txt")},
				},
				{
					"foo/bar.txt": {Mode: 0644, Data: []byte("foo/bar2")},
					"bar/zab.txt": {Mode: 0644, Data: []byte("bar/zab.txt2")},
				},
				{
					"foo/bar.txt": {Mode: 0644, Data: []byte("foo/bar")},
				},
			},
		},
	}

	for _, tc := range cases {
		targetDir, err := utiltesting.MkTmpdir("atomic-write")
		if err != nil {
			t.Errorf("%v: unexpected error creating tmp dir: %v", tc.name, err)
			continue
		}

		writer := &AtomicWriter{targetDir: targetDir, logContext: "-test-"}

		for _, payload := range tc.payloads {
			writer.Write(payload)

			checkVolumeContents(targetDir, tc.name, payload, t)
		}
	}
}

func checkVolumeContents(targetDir, tcName string, payload map[string]FileProjection, t *testing.T) {
	// use filepath.Walk to reconstruct the payload, then deep equal
	observedPayload := make(map[string]FileProjection)
	visitor := func(path string, info os.FileInfo, err error) error {
		if info.Mode().IsRegular() || info.IsDir() {
			return nil
		}

		relativePath := strings.TrimPrefix(path, targetDir)
		relativePath = strings.TrimPrefix(relativePath, "/")
		if strings.HasPrefix(relativePath, "..") {
			return nil
		}

		content, err := ioutil.ReadFile(path)
		if err != nil {
			return err
		}
		fileInfo, err := os.Stat(path)
		if err != nil {
			return err
		}
		mode := int32(fileInfo.Mode())

		observedPayload[relativePath] = FileProjection{Data: content, Mode: mode}

		return nil
	}

	err := filepath.Walk(targetDir, visitor)
	if err != nil {
		t.Errorf("%v: unexpected error walking directory: %v", tcName, err)
	}

	cleanPathPayload := make(map[string]FileProjection, len(payload))
	for k, v := range payload {
		cleanPathPayload[path.Clean(k)] = v
	}

	if !reflect.DeepEqual(cleanPathPayload, observedPayload) {
		t.Errorf("%v: payload and observed payload do not match.", tcName)
	}
}