diff --git a/vendor/manifest b/vendor/manifest
index 920c3da86..40f904099 100644
--- a/vendor/manifest
+++ b/vendor/manifest
@@ -34,7 +34,7 @@
 		{
 			"importpath": "github.com/kurin/blazer",
 			"repository": "https://github.com/kurin/blazer",
-			"revision": "48de0a1e4d21fba201aff7fefdf3e5e7735b1439",
+			"revision": "d1b9d31c8641e46f2651fe564ee9ddb857c1ed29",
 			"branch": "master"
 		},
 		{
diff --git a/vendor/src/github.com/kurin/blazer/b2/b2.go b/vendor/src/github.com/kurin/blazer/b2/b2.go
index bfde1cee8..66c8c1c68 100644
--- a/vendor/src/github.com/kurin/blazer/b2/b2.go
+++ b/vendor/src/github.com/kurin/blazer/b2/b2.go
@@ -28,7 +28,6 @@
 package b2
 
 import (
-	"bytes"
 	"fmt"
 	"io"
 	"net/http"
@@ -64,7 +63,10 @@ func NewClient(ctx context.Context, account, key string, opts ...ClientOption) (
 }
 
 type clientOptions struct {
-	transport http.RoundTripper
+	transport       http.RoundTripper
+	failSomeUploads bool
+	expireTokens    bool
+	capExceeded     bool
 }
 
 // A ClientOption allows callers to adjust various per-client settings.
@@ -78,6 +80,30 @@ func Transport(rt http.RoundTripper) ClientOption {
 	}
 }
 
+// FailSomeUploads requests intermittent upload failures from the B2 service.
+// This is mostly useful for testing.
+func FailSomeUploads() ClientOption {
+	return func(c *clientOptions) {
+		c.failSomeUploads = true
+	}
+}
+
+// ExpireSomeAuthTokens requests intermittent authentication failures from the
+// B2 service.
+func ExpireSomeAuthTokens() ClientOption {
+	return func(c *clientOptions) {
+		c.expireTokens = true
+	}
+}
+
+// ForceCapExceeded requests a cap limit from the B2 service.  This causes all
+// uploads to be treated as if they would exceed the configure B2 capacity.
+func ForceCapExceeded() ClientOption {
+	return func(c *clientOptions) {
+		c.capExceeded = true
+	}
+}
+
 // Bucket is a reference to a B2 bucket.
 type Bucket struct {
 	b beBucketInterface
@@ -306,9 +332,11 @@ func (o *Object) Name() string {
 
 // Attrs returns an object's attributes.
 func (o *Object) Attrs(ctx context.Context) (*Attrs, error) {
-	if err := o.ensure(ctx); err != nil {
+	f, err := o.b.b.downloadFileByName(ctx, o.name, 0, 1)
+	if err != nil {
 		return nil, err
 	}
+	o.f = o.b.b.file(f.id())
 	fi, err := o.f.getFileInfo(ctx)
 	if err != nil {
 		return nil, err
@@ -403,7 +431,7 @@ func (o *Object) NewRangeReader(ctx context.Context, offset, length int64) *Read
 		cancel: cancel,
 		o:      o,
 		name:   o.name,
-		chunks: make(map[int]*bytes.Buffer),
+		chunks: make(map[int]*rchunk),
 		length: length,
 		offset: offset,
 	}
diff --git a/vendor/src/github.com/kurin/blazer/b2/b2_test.go b/vendor/src/github.com/kurin/blazer/b2/b2_test.go
index 3f974438d..9748528af 100644
--- a/vendor/src/github.com/kurin/blazer/b2/b2_test.go
+++ b/vendor/src/github.com/kurin/blazer/b2/b2_test.go
@@ -196,8 +196,18 @@ func (t *testBucket) listFileVersions(ctx context.Context, count int, a, b, c, d
 }
 
 func (t *testBucket) downloadFileByName(_ context.Context, name string, offset, size int64) (b2FileReaderInterface, error) {
+	f := t.files[name]
+	end := int(offset + size)
+	if end >= len(f) {
+		end = len(f)
+	}
+	if int(offset) >= len(f) {
+		return nil, errNoMoreContent
+	}
 	return &testFileReader{
-		b: ioutil.NopCloser(bytes.NewBufferString(t.files[name][offset : offset+size])),
+		b: ioutil.NopCloser(bytes.NewBufferString(f[offset:end])),
+		s: end - int(offset),
+		n: name,
 	}, nil
 }
 
@@ -205,7 +215,8 @@ func (t *testBucket) hideFile(context.Context, string) (b2FileInterface, error)
 func (t *testBucket) getDownloadAuthorization(context.Context, string, time.Duration) (string, error) {
 	return "", nil
 }
-func (t *testBucket) baseURL() string { return "" }
+func (t *testBucket) baseURL() string                { return "" }
+func (t *testBucket) file(id string) b2FileInterface { return nil }
 
 type testURL struct {
 	files map[string]string
@@ -310,12 +321,14 @@ func (t *testFile) deleteFileVersion(context.Context) error {
 
 type testFileReader struct {
 	b io.ReadCloser
-	s int64
+	s int
+	n string
 }
 
 func (t *testFileReader) Read(p []byte) (int, error)                      { return t.b.Read(p) }
 func (t *testFileReader) Close() error                                    { return nil }
-func (t *testFileReader) stats() (int, string, string, map[string]string) { return 0, "", "", nil }
+func (t *testFileReader) stats() (int, string, string, map[string]string) { return t.s, "", "", nil }
+func (t *testFileReader) id() string                                      { return t.n }
 
 type zReader struct{}
 
@@ -569,6 +582,46 @@ func TestReadWrite(t *testing.T) {
 	}
 }
 
+func TestReadRangeReturnsRight(t *testing.T) {
+	ctx := context.Background()
+	ctx, cancel := context.WithTimeout(ctx, 10*time.Second)
+	defer cancel()
+
+	client := &Client{
+		backend: &beRoot{
+			b2i: &testRoot{
+				bucketMap: make(map[string]map[string]string),
+				errs:      &errCont{},
+			},
+		},
+	}
+
+	bucket, err := client.NewBucket(ctx, bucketName, &BucketAttrs{Type: Private})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer func() {
+		if err := bucket.Delete(ctx); err != nil {
+			t.Error(err)
+		}
+	}()
+
+	obj, _, err := writeFile(ctx, bucket, "file", 1e6+42, 1e8)
+	if err != nil {
+		t.Fatal(err)
+	}
+	r := obj.NewRangeReader(ctx, 200, 1400)
+	r.ChunkSize = 1000
+
+	i, err := io.Copy(ioutil.Discard, r)
+	if err != nil {
+		t.Error(err)
+	}
+	if i != 1400 {
+		t.Errorf("NewRangeReader(_, 200, 1400): want 1400, got %d", i)
+	}
+}
+
 func TestWriterReturnsError(t *testing.T) {
 	ctx := context.Background()
 	ctx, cancel := context.WithTimeout(ctx, 10*time.Second)
diff --git a/vendor/src/github.com/kurin/blazer/b2/backend.go b/vendor/src/github.com/kurin/blazer/b2/backend.go
index 843a997a8..9862988c3 100644
--- a/vendor/src/github.com/kurin/blazer/b2/backend.go
+++ b/vendor/src/github.com/kurin/blazer/b2/backend.go
@@ -54,6 +54,7 @@ type beBucketInterface interface {
 	hideFile(context.Context, string) (beFileInterface, error)
 	getDownloadAuthorization(context.Context, string, time.Duration) (string, error)
 	baseURL() string
+	file(string) beFileInterface
 }
 
 type beBucket struct {
@@ -110,6 +111,7 @@ type beFileChunk struct {
 type beFileReaderInterface interface {
 	io.ReadCloser
 	stats() (int, string, string, map[string]string)
+	id() string
 }
 
 type beFileReader struct {
@@ -405,6 +407,13 @@ func (b *beBucket) baseURL() string {
 	return b.b2bucket.baseURL()
 }
 
+func (b *beBucket) file(id string) beFileInterface {
+	return &beFile{
+		b2file: b.b2bucket.file(id),
+		ri:     b.ri,
+	}
+}
+
 func (b *beURL) uploadFile(ctx context.Context, r io.ReadSeeker, size int, name, ct, sha1 string, info map[string]string) (beFileInterface, error) {
 	var file beFileInterface
 	f := func() error {
@@ -602,6 +611,8 @@ func (b *beFileReader) stats() (int, string, string, map[string]string) {
 	return b.b2fileReader.stats()
 }
 
+func (b *beFileReader) id() string { return b.b2fileReader.id() }
+
 func (b *beFileInfo) stats() (string, string, int64, string, map[string]string, string, time.Time) {
 	return b.name, b.sha, b.size, b.ct, b.info, b.status, b.stamp
 }
diff --git a/vendor/src/github.com/kurin/blazer/b2/baseline.go b/vendor/src/github.com/kurin/blazer/b2/baseline.go
index 5a00f526f..adfefcc75 100644
--- a/vendor/src/github.com/kurin/blazer/b2/baseline.go
+++ b/vendor/src/github.com/kurin/blazer/b2/baseline.go
@@ -16,6 +16,7 @@ package b2
 
 import (
 	"io"
+	"net/http"
 	"time"
 
 	"github.com/kurin/blazer/base"
@@ -50,6 +51,7 @@ type b2BucketInterface interface {
 	hideFile(context.Context, string) (b2FileInterface, error)
 	getDownloadAuthorization(context.Context, string, time.Duration) (string, error)
 	baseURL() string
+	file(string) b2FileInterface
 }
 
 type b2URLInterface interface {
@@ -81,6 +83,7 @@ type b2FileChunkInterface interface {
 type b2FileReaderInterface interface {
 	io.ReadCloser
 	stats() (int, string, string, map[string]string)
+	id() string
 }
 
 type b2FileInfoInterface interface {
@@ -138,6 +141,15 @@ func (b *b2Root) authorizeAccount(ctx context.Context, account, key string, opts
 	if c.transport != nil {
 		aopts = append(aopts, base.Transport(c.transport))
 	}
+	if c.failSomeUploads {
+		aopts = append(aopts, base.FailSomeUploads())
+	}
+	if c.expireTokens {
+		aopts = append(aopts, base.ExpireSomeAuthTokens())
+	}
+	if c.capExceeded {
+		aopts = append(aopts, base.ForceCapExceeded())
+	}
 	nb, err := base.AuthorizeAccount(ctx, account, key, aopts...)
 	if err != nil {
 		return err
@@ -303,6 +315,9 @@ func (b *b2Bucket) listFileVersions(ctx context.Context, count int, nextName, ne
 func (b *b2Bucket) downloadFileByName(ctx context.Context, name string, offset, size int64) (b2FileReaderInterface, error) {
 	fr, err := b.b.DownloadFileByName(ctx, name, offset, size)
 	if err != nil {
+		if code, _ := base.Code(err); code == http.StatusRequestedRangeNotSatisfiable {
+			return nil, errNoMoreContent
+		}
 		return nil, err
 	}
 	return &b2FileReader{fr}, nil
@@ -324,6 +339,8 @@ func (b *b2Bucket) baseURL() string {
 	return b.b.BaseURL()
 }
 
+func (b *b2Bucket) file(id string) b2FileInterface { return &b2File{b.b.File(id)} }
+
 func (b *b2URL) uploadFile(ctx context.Context, r io.Reader, size int, name, contentType, sha1 string, info map[string]string) (b2FileInterface, error) {
 	file, err := b.b.UploadFile(ctx, r, size, name, contentType, sha1, info)
 	if err != nil {
@@ -416,6 +433,8 @@ func (b *b2FileReader) stats() (int, string, string, map[string]string) {
 	return b.b.ContentLength, b.b.ContentType, b.b.SHA1, b.b.Info
 }
 
+func (b *b2FileReader) id() string { return b.b.ID }
+
 func (b *b2FileInfo) stats() (string, string, int64, string, map[string]string, string, time.Time) {
 	return b.b.Name, b.b.SHA1, b.b.Size, b.b.ContentType, b.b.Info, b.b.Status, b.b.Timestamp
 }
diff --git a/vendor/src/github.com/kurin/blazer/b2/integration_test.go b/vendor/src/github.com/kurin/blazer/b2/integration_test.go
index c96b4fb33..f24da99b4 100644
--- a/vendor/src/github.com/kurin/blazer/b2/integration_test.go
+++ b/vendor/src/github.com/kurin/blazer/b2/integration_test.go
@@ -25,8 +25,6 @@ import (
 	"testing"
 	"time"
 
-	"github.com/kurin/blazer/base"
-
 	"golang.org/x/net/context"
 )
 
@@ -37,16 +35,6 @@ const (
 	errVar = "B2_TRANSIENT_ERRORS"
 )
 
-func init() {
-	fail := os.Getenv(errVar)
-	switch fail {
-	case "", "0", "false":
-		return
-	}
-	base.FailSomeUploads = true
-	base.ExpireSomeAuthTokens = true
-}
-
 func TestReadWriteLive(t *testing.T) {
 	ctx := context.Background()
 	ctx, cancel := context.WithTimeout(ctx, 10*time.Minute)
@@ -144,6 +132,21 @@ func TestHideShowLive(t *testing.T) {
 	}
 }
 
+type cancelReader struct {
+	r    io.Reader
+	n, l int
+	c    func()
+}
+
+func (c *cancelReader) Read(p []byte) (int, error) {
+	n, err := c.r.Read(p)
+	c.n += n
+	if c.n >= c.l {
+		c.c()
+	}
+	return n, err
+}
+
 func TestResumeWriter(t *testing.T) {
 	ctx := context.Background()
 	ctx, cancel := context.WithTimeout(ctx, 10*time.Minute)
@@ -151,18 +154,11 @@ func TestResumeWriter(t *testing.T) {
 
 	w := bucket.Object("foo").NewWriter(ctx)
 	w.ChunkSize = 5e6
-	r := io.LimitReader(zReader{}, 15e6)
-	go func() {
-		// Cancel the context after the first chunk has been written.
-		ticker := time.NewTicker(time.Second)
-		defer ticker.Stop()
-		defer cancel()
-		for range ticker.C {
-			if w.cidx > 1 {
-				return
-			}
-		}
-	}()
+	r := &cancelReader{
+		r: io.LimitReader(zReader{}, 15e6),
+		l: 6e6,
+		c: cancel,
+	}
 	if _, err := io.Copy(w, r); err != context.Canceled {
 		t.Fatalf("io.Copy: wanted canceled context, got: %v", err)
 	}
@@ -392,6 +388,11 @@ func TestRangeReaderLive(t *testing.T) {
 			length: 2e6,
 			size:   1e6,
 		},
+		{
+			offset: 0,
+			length: 4e6,
+			size:   3e6,
+		},
 	}
 
 	for _, e := range table {
@@ -418,12 +419,12 @@ func TestRangeReaderLive(t *testing.T) {
 			continue
 		}
 		if read != e.size {
-			t.Errorf("read %d bytes, wanted %d bytes", read, e.size)
+			t.Errorf("NewRangeReader(_, %d, %d): read %d bytes, wanted %d bytes", e.offset, e.length, read, e.size)
 		}
 		got := fmt.Sprintf("%x", hr.Sum(nil))
 		want := fmt.Sprintf("%x", hw.Sum(nil))
 		if got != want {
-			t.Errorf("bad hash, got %q, want %q", got, want)
+			t.Errorf("NewRangeReader(_, %d, %d): got %q, want %q", e.offset, e.length, got, want)
 		}
 	}
 }
@@ -661,7 +662,7 @@ func startLiveTest(ctx context.Context, t *testing.T) (*Bucket, func()) {
 		t.Skipf("B2_ACCOUNT_ID or B2_SECRET_KEY unset; skipping integration tests")
 		return nil, nil
 	}
-	client, err := NewClient(ctx, id, key)
+	client, err := NewClient(ctx, id, key, FailSomeUploads(), ExpireSomeAuthTokens())
 	if err != nil {
 		t.Fatal(err)
 		return nil, nil
diff --git a/vendor/src/github.com/kurin/blazer/b2/reader.go b/vendor/src/github.com/kurin/blazer/b2/reader.go
index cba76b46c..9b293710e 100644
--- a/vendor/src/github.com/kurin/blazer/b2/reader.go
+++ b/vendor/src/github.com/kurin/blazer/b2/reader.go
@@ -16,6 +16,7 @@ package b2
 
 import (
 	"bytes"
+	"errors"
 	"io"
 	"sync"
 
@@ -24,6 +25,8 @@ import (
 	"golang.org/x/net/context"
 )
 
+var errNoMoreContent = errors.New("416: out of content")
+
 // Reader reads files from B2.
 type Reader struct {
 	// ConcurrentDownloads is the number of simultaneous downloads to pull from
@@ -42,16 +45,15 @@ type Reader struct {
 	name   string
 	offset int64 // the start of the file
 	length int64 // the length to read, or -1
-	size   int64 // the end of the file, in absolute terms
 	csize  int   // chunk size
 	read   int   // amount read
 	chwid  int   // chunks written
 	chrid  int   // chunks read
-	chbuf  chan *bytes.Buffer
+	chbuf  chan *rchunk
 	init   sync.Once
 	rmux   sync.Mutex // guards rcond
 	rcond  *sync.Cond
-	chunks map[int]*bytes.Buffer
+	chunks map[int]*rchunk
 
 	emux sync.RWMutex // guards err, believe it or not
 	err  error
@@ -60,6 +62,11 @@ type Reader struct {
 	smap map[int]*meteredReader
 }
 
+type rchunk struct {
+	bytes.Buffer
+	final bool
+}
+
 // Close frees resources associated with the download.
 func (r *Reader) Close() error {
 	r.cancel()
@@ -93,7 +100,7 @@ func (r *Reader) getErr() error {
 func (r *Reader) thread() {
 	go func() {
 		for {
-			var buf *bytes.Buffer
+			var buf *rchunk
 			select {
 			case b, ok := <-r.chbuf:
 				if !ok {
@@ -109,26 +116,31 @@ func (r *Reader) thread() {
 			r.rmux.Unlock()
 			offset := int64(chunkID*r.csize) + r.offset
 			size := int64(r.csize)
-			if offset >= r.size {
-				// Send an empty chunk.  This is necessary to prevent a deadlock when
-				// this is the very first chunk.
+			if r.length > 0 {
+				if size > r.length {
+					buf.final = true
+					size = r.length
+				}
+				r.length -= size
+			}
+		redo:
+			fr, err := r.o.b.b.downloadFileByName(r.ctx, r.name, offset, size)
+			if err == errNoMoreContent {
+				// this read generated a 416 so we are entirely past the end of the object
+				buf.final = true
 				r.rmux.Lock()
 				r.chunks[chunkID] = buf
 				r.rmux.Unlock()
 				r.rcond.Broadcast()
 				return
 			}
-			if offset+size > r.size {
-				size = r.size - offset
-			}
-		redo:
-			fr, err := r.o.b.b.downloadFileByName(r.ctx, r.name, offset, size)
 			if err != nil {
 				r.setErr(err)
 				r.rcond.Broadcast()
 				return
 			}
-			mr := &meteredReader{r: &fakeSeeker{fr}, size: int(size)}
+			rsize, _, _, _ := fr.stats()
+			mr := &meteredReader{r: &fakeSeeker{fr}, size: int(rsize)}
 			r.smux.Lock()
 			r.smap[chunkID] = mr
 			r.smux.Unlock()
@@ -136,9 +148,9 @@ func (r *Reader) thread() {
 			r.smux.Lock()
 			r.smap[chunkID] = nil
 			r.smux.Unlock()
-			if i < size || err == io.ErrUnexpectedEOF {
+			if i < int64(rsize) || err == io.ErrUnexpectedEOF {
 				// Probably the network connection was closed early.  Retry.
-				blog.V(1).Infof("b2 reader %d: got %dB of %dB; retrying", chunkID, i, size)
+				blog.V(1).Infof("b2 reader %d: got %dB of %dB; retrying", chunkID, i, rsize)
 				buf.Reset()
 				goto redo
 			}
@@ -155,8 +167,8 @@ func (r *Reader) thread() {
 	}()
 }
 
-func (r *Reader) curChunk() (*bytes.Buffer, error) {
-	ch := make(chan *bytes.Buffer)
+func (r *Reader) curChunk() (*rchunk, error) {
+	ch := make(chan *rchunk)
 	go func() {
 		r.rmux.Lock()
 		defer r.rmux.Unlock()
@@ -185,17 +197,6 @@ func (r *Reader) initFunc() {
 	r.smap = make(map[int]*meteredReader)
 	r.smux.Unlock()
 	r.o.b.c.addReader(r)
-	if err := r.o.ensure(r.ctx); err != nil {
-		r.setErr(err)
-		return
-	}
-	r.size = r.o.f.size()
-	if r.length >= 0 && r.offset+r.length < r.size {
-		r.size = r.offset + r.length
-	}
-	if r.offset > r.size {
-		r.offset = r.size
-	}
 	r.rcond = sync.NewCond(&r.rmux)
 	cr := r.ConcurrentDownloads
 	if cr < 1 {
@@ -205,10 +206,10 @@ func (r *Reader) initFunc() {
 		r.ChunkSize = 1e7
 	}
 	r.csize = r.ChunkSize
-	r.chbuf = make(chan *bytes.Buffer, cr)
+	r.chbuf = make(chan *rchunk, cr)
 	for i := 0; i < cr; i++ {
 		r.thread()
-		r.chbuf <- &bytes.Buffer{}
+		r.chbuf <- &rchunk{}
 	}
 }
 
@@ -226,7 +227,7 @@ func (r *Reader) Read(p []byte) (int, error) {
 	n, err := chunk.Read(p)
 	r.read += n
 	if err == io.EOF {
-		if int64(r.read) >= r.size-r.offset {
+		if chunk.final {
 			close(r.chbuf)
 			r.setErrNoCancel(err)
 			return n, err
diff --git a/vendor/src/github.com/kurin/blazer/b2/writer.go b/vendor/src/github.com/kurin/blazer/b2/writer.go
index 0605f947b..3026460ea 100644
--- a/vendor/src/github.com/kurin/blazer/b2/writer.go
+++ b/vendor/src/github.com/kurin/blazer/b2/writer.go
@@ -107,7 +107,7 @@ func (w *Writer) setErr(err error) {
 	w.emux.Lock()
 	defer w.emux.Unlock()
 	if w.err == nil {
-		blog.V(0).Infof("error writing %s: %v", w.name, err)
+		blog.V(1).Infof("error writing %s: %v", w.name, err)
 		w.err = err
 		w.cancel()
 	}
@@ -134,15 +134,15 @@ func (w *Writer) completeChunk(id int) {
 var gid int32
 
 func (w *Writer) thread() {
+	w.wg.Add(1)
 	go func() {
+		defer w.wg.Done()
 		id := atomic.AddInt32(&gid, 1)
 		fc, err := w.file.getUploadPartURL(w.ctx)
 		if err != nil {
 			w.setErr(err)
 			return
 		}
-		w.wg.Add(1)
-		defer w.wg.Done()
 		for {
 			chunk, ok := <-w.ready
 			if !ok {
diff --git a/vendor/src/github.com/kurin/blazer/base/base.go b/vendor/src/github.com/kurin/blazer/base/base.go
index 7c87be907..9ae118b15 100644
--- a/vendor/src/github.com/kurin/blazer/base/base.go
+++ b/vendor/src/github.com/kurin/blazer/base/base.go
@@ -208,7 +208,10 @@ func millitime(t int64) time.Time {
 }
 
 type b2Options struct {
-	transport http.RoundTripper
+	transport       http.RoundTripper
+	failSomeUploads bool
+	expireTokens    bool
+	capExceeded     bool
 }
 
 func (o *b2Options) getTransport() http.RoundTripper {
@@ -272,20 +275,6 @@ func (rb *requestBody) getBody() io.Reader {
 	return rb.body
 }
 
-var (
-	// FailSomeUploads causes B2 to return errors, randomly, to some RPCs.  It is
-	// intended to be used for integration testing.
-	FailSomeUploads = false
-
-	// ExpireSomeAuthTokens causes B2 to expire auth tokens frequently, testing
-	// account reauthentication.
-	ExpireSomeAuthTokens = false
-
-	// ForceCapExceeded causes B2 to reject all uploads with capacity limit
-	// failures.
-	ForceCapExceeded = false
-)
-
 var reqID int64
 
 func (o *b2Options) makeRequest(ctx context.Context, method, verb, url string, b2req, b2resp interface{}, headers map[string]string, body *requestBody) error {
@@ -311,13 +300,13 @@ func (o *b2Options) makeRequest(ctx context.Context, method, verb, url string, b
 	}
 	req.Header.Set("X-Blazer-Request-ID", fmt.Sprintf("%d", atomic.AddInt64(&reqID, 1)))
 	req.Header.Set("X-Blazer-Method", method)
-	if FailSomeUploads {
+	if o.failSomeUploads {
 		req.Header.Add("X-Bz-Test-Mode", "fail_some_uploads")
 	}
-	if ExpireSomeAuthTokens {
+	if o.expireTokens {
 		req.Header.Add("X-Bz-Test-Mode", "expire_some_account_authorization_tokens")
 	}
-	if ForceCapExceeded {
+	if o.capExceeded {
 		req.Header.Add("X-Bz-Test-Mode", "force_cap_exceeded")
 	}
 	cancel := make(chan struct{})
@@ -396,6 +385,30 @@ func Transport(rt http.RoundTripper) AuthOption {
 	}
 }
 
+// FailSomeUploads requests intermittent upload failures from the B2 service.
+// This is mostly useful for testing.
+func FailSomeUploads() AuthOption {
+	return func(o *b2Options) {
+		o.failSomeUploads = true
+	}
+}
+
+// ExpireSomeAuthTokens requests intermittent authentication failures from the
+// B2 service.
+func ExpireSomeAuthTokens() AuthOption {
+	return func(o *b2Options) {
+		o.expireTokens = true
+	}
+}
+
+// ForceCapExceeded requests a cap limit from the B2 service.  This causes all
+// uploads to be treated as if they would exceed the configure B2 capacity.
+func ForceCapExceeded() AuthOption {
+	return func(o *b2Options) {
+		o.capExceeded = true
+	}
+}
+
 type LifecycleRule struct {
 	Prefix                 string
 	DaysNewUntilHidden     int
@@ -604,6 +617,12 @@ type File struct {
 	b2        *B2
 }
 
+// File returns a bare File struct, but with the appropriate id and b2
+// interfaces.
+func (b *Bucket) File(id string) *File {
+	return &File{id: id, b2: b.b2}
+}
+
 // UploadFile wraps b2_upload_file.
 func (url *URL) UploadFile(ctx context.Context, r io.Reader, size int, name, contentType, sha1 string, info map[string]string) (*File, error) {
 	headers := map[string]string{
@@ -910,6 +929,7 @@ type FileReader struct {
 	ContentLength int
 	ContentType   string
 	SHA1          string
+	ID            string
 	Info          map[string]string
 }
 
@@ -971,6 +991,7 @@ func (b *Bucket) DownloadFileByName(ctx context.Context, name string, offset, si
 	return &FileReader{
 		ReadCloser:    reply.resp.Body,
 		SHA1:          reply.resp.Header.Get("X-Bz-Content-Sha1"),
+		ID:            reply.resp.Header.Get("X-Bz-File-Id"),
 		ContentType:   reply.resp.Header.Get("Content-Type"),
 		ContentLength: int(clen),
 		Info:          info,