cmd/swarm, swarm/api/http, swarm/bmt, swarm/fuse, swarm/network/stream, swarm/storage, swarm/storage/encryption, swarm/testutil: use pseudo-random instead of crypto-random for test files content generation (#18083)

- Replace "crypto/rand" to "math/rand" for files content generation
- Remove swarm/network_test.go.Shuffle and swarm/btm/btm_test.go.Shuffle - because go1.9 support dropped (see https://github.com/ethereum/go-ethereum/pull/17807 and comments to swarm/network_test.go.Shuffle)

1 files changed, 66 insertions, 97 deletions

diff --git a/swarm/fuse/swarmfs_test.go b/swarm/fuse/swarmfs_test.go
index 87d918550..460e31c4e 100644
--- a/swarm/fuse/swarmfs_test.go
+++ b/swarm/fuse/swarmfs_test.go
@@ -20,20 +20,19 @@ package fuse
 
 import (
 	"bytes"
-	"crypto/rand"
 	"flag"
 	"fmt"
 	"io"
 	"io/ioutil"
+	"math/rand"
 	"os"
 	"path/filepath"
 	"testing"
 
+	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/swarm/api"
 	"github.com/ethereum/go-ethereum/swarm/storage"
-
-	"github.com/ethereum/go-ethereum/log"
-
+	"github.com/ethereum/go-ethereum/swarm/testutil"
 	colorable "github.com/mattn/go-colorable"
 )
 
@@ -229,12 +228,6 @@ func checkFile(t *testing.T, testMountDir, fname string, contents []byte) {
 	}
 }
 
-func getRandomBytes(size int) []byte {
-	contents := make([]byte, size)
-	rand.Read(contents)
-	return contents
-}
-
 func isDirEmpty(name string) bool {
 	f, err := os.Open(name)
 	if err != nil {
@@ -328,22 +321,22 @@ func (ta *testAPI) mountListAndUnmount(t *testing.T, toEncrypt bool) {
 	dat.testMountDir = filepath.Join(dat.testDir, "testMountDir")
 	dat.files = make(map[string]fileInfo)
 
-	dat.files["1.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
-	dat.files["2.txt"] = fileInfo{0711, 333, 444, getRandomBytes(10)}
-	dat.files["3.txt"] = fileInfo{0622, 333, 444, getRandomBytes(100)}
-	dat.files["4.txt"] = fileInfo{0533, 333, 444, getRandomBytes(1024)}
-	dat.files["5.txt"] = fileInfo{0544, 333, 444, getRandomBytes(10)}
-	dat.files["6.txt"] = fileInfo{0555, 333, 444, getRandomBytes(10)}
-	dat.files["7.txt"] = fileInfo{0666, 333, 444, getRandomBytes(10)}
-	dat.files["8.txt"] = fileInfo{0777, 333, 333, getRandomBytes(10)}
-	dat.files["11.txt"] = fileInfo{0777, 333, 444, getRandomBytes(10)}
-	dat.files["111.txt"] = fileInfo{0777, 333, 444, getRandomBytes(10)}
-	dat.files["two/2.txt"] = fileInfo{0777, 333, 444, getRandomBytes(10)}
-	dat.files["two/2/2.txt"] = fileInfo{0777, 333, 444, getRandomBytes(10)}
-	dat.files["two/2./2.txt"] = fileInfo{0777, 444, 444, getRandomBytes(10)}
-	dat.files["twice/2.txt"] = fileInfo{0777, 444, 333, getRandomBytes(200)}
-	dat.files["one/two/three/four/five/six/seven/eight/nine/10.txt"] = fileInfo{0777, 333, 444, getRandomBytes(10240)}
-	dat.files["one/two/three/four/five/six/six"] = fileInfo{0777, 333, 444, getRandomBytes(10)}
+	dat.files["1.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
+	dat.files["2.txt"] = fileInfo{0711, 333, 444, testutil.RandomBytes(2, 10)}
+	dat.files["3.txt"] = fileInfo{0622, 333, 444, testutil.RandomBytes(3, 100)}
+	dat.files["4.txt"] = fileInfo{0533, 333, 444, testutil.RandomBytes(4, 1024)}
+	dat.files["5.txt"] = fileInfo{0544, 333, 444, testutil.RandomBytes(5, 10)}
+	dat.files["6.txt"] = fileInfo{0555, 333, 444, testutil.RandomBytes(6, 10)}
+	dat.files["7.txt"] = fileInfo{0666, 333, 444, testutil.RandomBytes(7, 10)}
+	dat.files["8.txt"] = fileInfo{0777, 333, 333, testutil.RandomBytes(8, 10)}
+	dat.files["11.txt"] = fileInfo{0777, 333, 444, testutil.RandomBytes(9, 10)}
+	dat.files["111.txt"] = fileInfo{0777, 333, 444, testutil.RandomBytes(10, 10)}
+	dat.files["two/2.txt"] = fileInfo{0777, 333, 444, testutil.RandomBytes(11, 10)}
+	dat.files["two/2/2.txt"] = fileInfo{0777, 333, 444, testutil.RandomBytes(12, 10)}
+	dat.files["two/2./2.txt"] = fileInfo{0777, 444, 444, testutil.RandomBytes(13, 10)}
+	dat.files["twice/2.txt"] = fileInfo{0777, 444, 333, testutil.RandomBytes(14, 200)}
+	dat.files["one/two/three/four/five/six/seven/eight/nine/10.txt"] = fileInfo{0777, 333, 444, testutil.RandomBytes(15, 10240)}
+	dat.files["one/two/three/four/five/six/six"] = fileInfo{0777, 333, 444, testutil.RandomBytes(16, 10)}
 
 	dat, err = ta.uploadAndMount(dat, t)
 	if err != nil {
@@ -386,7 +379,7 @@ func (ta *testAPI) runMaxMounts(t *testing.T, toEncrypt bool) {
 	dat.testUploadDir = filepath.Join(dat.testDir, "max-upload1")
 	dat.testMountDir = filepath.Join(dat.testDir, "max-mount1")
 	dat.files = make(map[string]fileInfo)
-	dat.files["1.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
+	dat.files["1.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
 
 	dat, err = ta.uploadAndMount(dat, t)
 	if err != nil {
@@ -396,7 +389,7 @@ func (ta *testAPI) runMaxMounts(t *testing.T, toEncrypt bool) {
 
 	dat.testUploadDir = filepath.Join(dat.testDir, "max-upload2")
 	dat.testMountDir = filepath.Join(dat.testDir, "max-mount2")
-	dat.files["2.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
+	dat.files["2.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
 
 	dat, err = ta.uploadAndMount(dat, t)
 	if err != nil {
@@ -405,7 +398,7 @@ func (ta *testAPI) runMaxMounts(t *testing.T, toEncrypt bool) {
 
 	dat.testUploadDir = filepath.Join(dat.testDir, "max-upload3")
 	dat.testMountDir = filepath.Join(dat.testDir, "max-mount3")
-	dat.files["3.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
+	dat.files["3.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
 
 	dat, err = ta.uploadAndMount(dat, t)
 	if err != nil {
@@ -414,7 +407,7 @@ func (ta *testAPI) runMaxMounts(t *testing.T, toEncrypt bool) {
 
 	dat.testUploadDir = filepath.Join(dat.testDir, "max-upload4")
 	dat.testMountDir = filepath.Join(dat.testDir, "max-mount4")
-	dat.files["4.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
+	dat.files["4.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
 
 	dat, err = ta.uploadAndMount(dat, t)
 	if err != nil {
@@ -423,7 +416,7 @@ func (ta *testAPI) runMaxMounts(t *testing.T, toEncrypt bool) {
 
 	dat.testUploadDir = filepath.Join(dat.testDir, "max-upload5")
 	dat.testMountDir = filepath.Join(dat.testDir, "max-mount5")
-	dat.files["5.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
+	dat.files["5.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
 
 	dat, err = ta.uploadAndMount(dat, t)
 	if err != nil {
@@ -436,7 +429,7 @@ func (ta *testAPI) runMaxMounts(t *testing.T, toEncrypt bool) {
 	if err != nil {
 		t.Fatalf("Couldn't create upload dir 6: %v", err)
 	}
-	dat.files["6.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
+	dat.files["6.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
 	testMountDir6 := filepath.Join(dat.testDir, "max-mount6")
 	err = os.MkdirAll(testMountDir6, 0777)
 	if err != nil {
@@ -475,7 +468,7 @@ func (ta *testAPI) remount(t *testing.T, toEncrypt bool) {
 	dat.testMountDir = filepath.Join(dat.testDir, "remount-mount1")
 	dat.files = make(map[string]fileInfo)
 
-	dat.files["1.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
+	dat.files["1.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
 
 	dat, err = ta.uploadAndMount(dat, t)
 	if err != nil {
@@ -494,7 +487,7 @@ func (ta *testAPI) remount(t *testing.T, toEncrypt bool) {
 	}
 
 	// mount a different hash in already mounted point
-	dat.files["2.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
+	dat.files["2.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
 	testUploadDir2, err3 := addDir(dat.testDir, "remount-upload2")
 	if err3 != nil {
 		t.Fatalf("Error creating second upload dir: %v", err3)
@@ -543,7 +536,7 @@ func (ta *testAPI) unmount(t *testing.T, toEncrypt bool) {
 	dat.testUploadDir = filepath.Join(dat.testDir, "ex-upload1")
 	dat.testMountDir = filepath.Join(dat.testDir, "ex-mount1")
 	dat.files = make(map[string]fileInfo)
-	dat.files["1.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
+	dat.files["1.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
 
 	dat, err = ta.uploadAndMount(dat, t)
 	if err != nil {
@@ -591,7 +584,7 @@ func (ta *testAPI) unmountWhenResourceBusy(t *testing.T, toEncrypt bool) {
 	dat.testUploadDir = filepath.Join(dat.testDir, "ex-upload1")
 	dat.testMountDir = filepath.Join(dat.testDir, "ex-mount1")
 	dat.files = make(map[string]fileInfo)
-	dat.files["1.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
+	dat.files["1.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
 
 	dat, err = ta.uploadAndMount(dat, t)
 	if err != nil {
@@ -609,7 +602,7 @@ func (ta *testAPI) unmountWhenResourceBusy(t *testing.T, toEncrypt bool) {
 	//we need to manually close the file before mount for this test
 	//but let's defer too in case of errors
 	defer d.Close()
-	_, err = d.Write(getRandomBytes(10))
+	_, err = d.Write(testutil.RandomBytes(1, 10))
 	if err != nil {
 		t.Fatalf("Couldn't write to file: %v", err)
 	}
@@ -667,7 +660,7 @@ func (ta *testAPI) seekInMultiChunkFile(t *testing.T, toEncrypt bool) {
 	dat.testUploadDir = filepath.Join(dat.testDir, "seek-upload1")
 	dat.testMountDir = filepath.Join(dat.testDir, "seek-mount")
 	dat.files = make(map[string]fileInfo)
-	dat.files["1.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10240)}
+	dat.files["1.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10240)}
 
 	dat, err = ta.uploadAndMount(dat, t)
 	if err != nil {
@@ -733,9 +726,9 @@ func (ta *testAPI) createNewFile(t *testing.T, toEncrypt bool) {
 	dat.testUploadDir = filepath.Join(dat.testDir, "create-upload1")
 	dat.testMountDir = filepath.Join(dat.testDir, "create-mount")
 	dat.files = make(map[string]fileInfo)
-	dat.files["1.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
-	dat.files["five.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
-	dat.files["six.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
+	dat.files["1.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
+	dat.files["five.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(2, 10)}
+	dat.files["six.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(3, 10)}
 
 	dat, err = ta.uploadAndMount(dat, t)
 	if err != nil {
@@ -751,11 +744,7 @@ func (ta *testAPI) createNewFile(t *testing.T, toEncrypt bool) {
 	}
 	defer d.Close()
 	log.Debug("Opened file")
-	contents := make([]byte, 11)
-	_, err = rand.Read(contents)
-	if err != nil {
-		t.Fatalf("Could not rand read contents %v", err)
-	}
+	contents := testutil.RandomBytes(1, 11)
 	log.Debug("content read")
 	_, err = d.Write(contents)
 	if err != nil {
@@ -815,7 +804,7 @@ func (ta *testAPI) createNewFileInsideDirectory(t *testing.T, toEncrypt bool) {
 	dat.testUploadDir = filepath.Join(dat.testDir, "createinsidedir-upload")
 	dat.testMountDir = filepath.Join(dat.testDir, "createinsidedir-mount")
 	dat.files = make(map[string]fileInfo)
-	dat.files["one/1.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
+	dat.files["one/1.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
 
 	dat, err = ta.uploadAndMount(dat, t)
 	if err != nil {
@@ -832,11 +821,7 @@ func (ta *testAPI) createNewFileInsideDirectory(t *testing.T, toEncrypt bool) {
 	}
 	defer d.Close()
 	log.Debug("File opened")
-	contents := make([]byte, 11)
-	_, err = rand.Read(contents)
-	if err != nil {
-		t.Fatalf("Error filling random bytes into byte array %v", err)
-	}
+	contents := testutil.RandomBytes(1, 11)
 	log.Debug("Content read")
 	_, err = d.Write(contents)
 	if err != nil {
@@ -896,7 +881,7 @@ func (ta *testAPI) createNewFileInsideNewDirectory(t *testing.T, toEncrypt bool)
 	dat.testUploadDir = filepath.Join(dat.testDir, "createinsidenewdir-upload")
 	dat.testMountDir = filepath.Join(dat.testDir, "createinsidenewdir-mount")
 	dat.files = make(map[string]fileInfo)
-	dat.files["1.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
+	dat.files["1.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
 
 	dat, err = ta.uploadAndMount(dat, t)
 	if err != nil {
@@ -916,11 +901,7 @@ func (ta *testAPI) createNewFileInsideNewDirectory(t *testing.T, toEncrypt bool)
 	}
 	defer d.Close()
 	log.Debug("File opened")
-	contents := make([]byte, 11)
-	_, err = rand.Read(contents)
-	if err != nil {
-		t.Fatalf("Error writing random bytes to byte array: %v", err)
-	}
+	contents := testutil.RandomBytes(1, 11)
 	log.Debug("content read")
 	_, err = d.Write(contents)
 	if err != nil {
@@ -976,9 +957,9 @@ func (ta *testAPI) removeExistingFile(t *testing.T, toEncrypt bool) {
 	dat.testUploadDir = filepath.Join(dat.testDir, "remove-upload")
 	dat.testMountDir = filepath.Join(dat.testDir, "remove-mount")
 	dat.files = make(map[string]fileInfo)
-	dat.files["1.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
-	dat.files["five.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
-	dat.files["six.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
+	dat.files["1.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
+	dat.files["five.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(2, 10)}
+	dat.files["six.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(3, 10)}
 
 	dat, err = ta.uploadAndMount(dat, t)
 	if err != nil {
@@ -1036,9 +1017,9 @@ func (ta *testAPI) removeExistingFileInsideDir(t *testing.T, toEncrypt bool) {
 	dat.testUploadDir = filepath.Join(dat.testDir, "remove-upload")
 	dat.testMountDir = filepath.Join(dat.testDir, "remove-mount")
 	dat.files = make(map[string]fileInfo)
-	dat.files["1.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
-	dat.files["one/five.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
-	dat.files["one/six.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
+	dat.files["1.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
+	dat.files["one/five.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(2, 10)}
+	dat.files["one/six.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(3, 10)}
 
 	dat, err = ta.uploadAndMount(dat, t)
 	if err != nil {
@@ -1104,9 +1085,9 @@ func (ta *testAPI) removeNewlyAddedFile(t *testing.T, toEncrypt bool) {
 	dat.testUploadDir = filepath.Join(dat.testDir, "removenew-upload")
 	dat.testMountDir = filepath.Join(dat.testDir, "removenew-mount")
 	dat.files = make(map[string]fileInfo)
-	dat.files["1.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
-	dat.files["five.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
-	dat.files["six.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
+	dat.files["1.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
+	dat.files["five.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(2, 10)}
+	dat.files["six.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(3, 10)}
 
 	dat, err = ta.uploadAndMount(dat, t)
 	if err != nil {
@@ -1127,11 +1108,7 @@ func (ta *testAPI) removeNewlyAddedFile(t *testing.T, toEncrypt bool) {
 	}
 	defer d.Close()
 	log.Debug("file opened")
-	contents := make([]byte, 11)
-	_, err = rand.Read(contents)
-	if err != nil {
-		t.Fatalf("Error writing random bytes to byte array: %v", err)
-	}
+	contents := testutil.RandomBytes(1, 11)
 	log.Debug("content read")
 	_, err = d.Write(contents)
 	if err != nil {
@@ -1201,9 +1178,9 @@ func (ta *testAPI) addNewFileAndModifyContents(t *testing.T, toEncrypt bool) {
 	dat.testUploadDir = filepath.Join(dat.testDir, "modifyfile-upload")
 	dat.testMountDir = filepath.Join(dat.testDir, "modifyfile-mount")
 	dat.files = make(map[string]fileInfo)
-	dat.files["1.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
-	dat.files["five.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
-	dat.files["six.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
+	dat.files["1.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
+	dat.files["five.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(2, 10)}
+	dat.files["six.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(3, 10)}
 
 	dat, err = ta.uploadAndMount(dat, t)
 	if err != nil {
@@ -1357,9 +1334,9 @@ func (ta *testAPI) removeEmptyDir(t *testing.T, toEncrypt bool) {
 	dat.testUploadDir = filepath.Join(dat.testDir, "rmdir-upload")
 	dat.testMountDir = filepath.Join(dat.testDir, "rmdir-mount")
 	dat.files = make(map[string]fileInfo)
-	dat.files["1.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
-	dat.files["five.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
-	dat.files["six.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
+	dat.files["1.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
+	dat.files["five.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(2, 10)}
+	dat.files["six.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(3, 10)}
 
 	dat, err = ta.uploadAndMount(dat, t)
 	if err != nil {
@@ -1406,9 +1383,9 @@ func (ta *testAPI) removeDirWhichHasFiles(t *testing.T, toEncrypt bool) {
 	dat.testUploadDir = filepath.Join(dat.testDir, "rmdir-upload")
 	dat.testMountDir = filepath.Join(dat.testDir, "rmdir-mount")
 	dat.files = make(map[string]fileInfo)
-	dat.files["one/1.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
-	dat.files["two/five.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
-	dat.files["two/six.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
+	dat.files["one/1.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
+	dat.files["two/five.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(2, 10)}
+	dat.files["two/six.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(3, 10)}
 
 	dat, err = ta.uploadAndMount(dat, t)
 	if err != nil {
@@ -1480,12 +1457,12 @@ func (ta *testAPI) removeDirWhichHasSubDirs(t *testing.T, toEncrypt bool) {
 	dat.testUploadDir = filepath.Join(dat.testDir, "rmsubdir-upload")
 	dat.testMountDir = filepath.Join(dat.testDir, "rmsubdir-mount")
 	dat.files = make(map[string]fileInfo)
-	dat.files["one/1.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
-	dat.files["two/three/2.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
-	dat.files["two/three/3.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
-	dat.files["two/four/5.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
-	dat.files["two/four/6.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
-	dat.files["two/four/six/7.txt"] = fileInfo{0700, 333, 444, getRandomBytes(10)}
+	dat.files["one/1.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(1, 10)}
+	dat.files["two/three/2.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(2, 10)}
+	dat.files["two/three/3.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(3, 10)}
+	dat.files["two/four/5.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(4, 10)}
+	dat.files["two/four/6.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(5, 10)}
+	dat.files["two/four/six/7.txt"] = fileInfo{0700, 333, 444, testutil.RandomBytes(6, 10)}
 
 	dat, err = ta.uploadAndMount(dat, t)
 	if err != nil {
@@ -1567,11 +1544,7 @@ func (ta *testAPI) appendFileContentsToEnd(t *testing.T, toEncrypt bool) {
 	dat.testMountDir = filepath.Join(dat.testDir, "appendlargefile-mount")
 	dat.files = make(map[string]fileInfo)
 
-	line1 := make([]byte, 10)
-	_, err = rand.Read(line1)
-	if err != nil {
-		t.Fatalf("Error writing random bytes to byte array: %v", err)
-	}
+	line1 := testutil.RandomBytes(1, 10)
 
 	dat.files["1.txt"] = fileInfo{0700, 333, 444, line1}
 
@@ -1588,11 +1561,7 @@ func (ta *testAPI) appendFileContentsToEnd(t *testing.T, toEncrypt bool) {
 	}
 	defer fd.Close()
 	log.Debug("file opened")
-	line2 := make([]byte, 5)
-	_, err = rand.Read(line2)
-	if err != nil {
-		t.Fatalf("Error writing random bytes to byte array: %v", err)
-	}
+	line2 := testutil.RandomBytes(1, 5)
 	log.Debug("line read")
 	_, err = fd.Seek(int64(len(line1)), 0)
 	if err != nil {