diff --git a/README.md b/README.md
index 432e95f..9ff884e 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,7 @@
 # imagorvideo
 
 [![Test Status](https://github.com/cshum/imagorvideo/workflows/test/badge.svg)](https://github.com/cshum/imagorvideo/actions/workflows/test.yml)
+[![Coverage Status](https://img.shields.io/coveralls/github/cshum/imagorvideo)](https://coveralls.io/github/cshum/imagorvideo?branch=master)
 [![Docker Hub](https://img.shields.io/badge/docker-shumc/imagorvideo-blue.svg)](https://hub.docker.com/r/shumc/imagorvideo/)
 [![GitHub Container Registry](https://ghcr-badge.herokuapp.com/cshum/imagorvideo/latest_tag?trim=major&label=ghcr.io&ignore=next,master&color=%23007ec6)](https://github.com/cshum/imagorvideo/pkgs/container/imagorvideo)
 
diff --git a/config_test.go b/config_test.go
new file mode 100644
index 0000000..c326014
--- /dev/null
+++ b/config_test.go
@@ -0,0 +1,17 @@
+package imagorvideo
+
+import (
+	"github.com/cshum/imagor"
+	"github.com/cshum/imagor/config"
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestConfig(t *testing.T) {
+	srv := config.CreateServer([]string{
+		"-ffmpeg-fallback-image", "https://foo.com/bar.jpg",
+	}, Config)
+	app := srv.App.(*imagor.Imagor)
+	processor := app.Processors[0].(*Processor)
+	assert.Equal(t, "https://foo.com/bar.jpg", processor.FallbackImage)
+}
diff --git a/ffmpeg/errors_test.go b/ffmpeg/errors_test.go
new file mode 100644
index 0000000..3b0d483
--- /dev/null
+++ b/ffmpeg/errors_test.go
@@ -0,0 +1,15 @@
+package ffmpeg
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestErrors(t *testing.T) {
+	assert.Equal(t, "ffmpeg: cannot allocate memory", ErrNoMem.Error())
+	assert.Equal(t, "ffmpeg: end of file", ErrEOF.Error())
+	assert.Equal(t, "ffmpeg: unknown error occurred", ErrUnknown.Error())
+	assert.Equal(t, "ffmpeg: decoder not found", ErrDecoderNotFound.Error())
+	assert.Equal(t, "ffmpeg: invalid data found when processing input", ErrInvalidData.Error())
+	assert.Equal(t, "ffmpeg: video or cover art size exceeds maximum allowed dimensions", ErrTooBig.Error())
+}
diff --git a/ffmpeg/ffmpeg_test.go b/ffmpeg/ffmpeg_test.go
index 6e6a711..e3a52af 100644
--- a/ffmpeg/ffmpeg_test.go
+++ b/ffmpeg/ffmpeg_test.go
@@ -26,7 +26,7 @@ var files = []string{
 
 var baseDir = "../testdata/"
 
-func TestAVContextMeta(t *testing.T) {
+func TestAVContext(t *testing.T) {
 	vips.Startup(nil)
 	SetFFmpegLogLevel(AVLogDebug)
 	logger := zap.NewExample()
@@ -43,7 +43,7 @@ func TestAVContextMeta(t *testing.T) {
 		}
 	})
 	require.NoError(t, os.MkdirAll(baseDir+"golden/meta", 0755))
-	require.NoError(t, os.MkdirAll(baseDir+"golden/result", 0755))
+	require.NoError(t, os.MkdirAll(baseDir+"golden/export", 0755))
 	t.Parallel()
 	for _, filename := range files {
 		t.Run(filename, func(t *testing.T) {
@@ -87,12 +87,3 @@ func TestAVContextMeta(t *testing.T) {
 		})
 	}
 }
-
-func TestErrors(t *testing.T) {
-	assert.Equal(t, "ffmpeg: cannot allocate memory", ErrNoMem.Error())
-	assert.Equal(t, "ffmpeg: end of file", ErrEOF.Error())
-	assert.Equal(t, "ffmpeg: unknown error occurred", ErrUnknown.Error())
-	assert.Equal(t, "ffmpeg: decoder not found", ErrDecoderNotFound.Error())
-	assert.Equal(t, "ffmpeg: invalid data found when processing input", ErrInvalidData.Error())
-	assert.Equal(t, "ffmpeg: video or cover art size exceeds maximum allowed dimensions", ErrTooBig.Error())
-}
diff --git a/processor.go b/processor.go
index a6edbc0..465de19 100644
--- a/processor.go
+++ b/processor.go
@@ -57,9 +57,6 @@ func (p *Processor) Process(ctx context.Context, in *imagor.Blob, params imagorp
 		if err == nil || out != nil {
 			return
 		}
-		if _, ok := err.(imagor.ErrForward); ok {
-			return
-		}
 		// fallback image on error
 		out = imagor.NewBlobFromBytes(transPixel)
 		if p.FallbackImage != "" {
@@ -85,8 +82,15 @@ func (p *Processor) Process(ctx context.Context, in *imagor.Blob, params imagorp
 		if reader, size, err = in.NewReader(); err != nil {
 			return
 		}
+		if size <= 0 {
+			// force read full file if size unknown
+			_ = reader.Close()
+			reader = nil
+		}
 	default:
-		if reader, size, err = in.NewReadSeeker(); err != nil {
+	}
+	if reader == nil {
+		if reader, size, err = in.NewReadSeeker(); err != nil || size <= 0 {
 			// write to temp file if read seeker not available
 			if reader, _, err = in.NewReader(); err != nil {
 				return
diff --git a/processor_test.go b/processor_test.go
new file mode 100644
index 0000000..f8a4316
--- /dev/null
+++ b/processor_test.go
@@ -0,0 +1,121 @@
+package imagorvideo
+
+import (
+	"context"
+	"fmt"
+	"github.com/cshum/imagor"
+	"github.com/cshum/imagor/imagorpath"
+	"github.com/cshum/imagor/storage/filestorage"
+	"github.com/cshum/imagor/vips"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.uber.org/zap"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"reflect"
+	"runtime"
+	"testing"
+)
+
+var testDataDir string
+
+func init() {
+	_, b, _, _ := runtime.Caller(0)
+	testDataDir = filepath.Join(filepath.Dir(b), "./testdata")
+}
+
+type test struct {
+	name string
+	path string
+}
+
+func TestProcessor(t *testing.T) {
+	v := vips.NewProcessor(vips.WithDebug(true))
+	require.NoError(t, v.Startup(context.Background()))
+	t.Cleanup(func() {
+		require.NoError(t, v.Shutdown(context.Background()))
+	})
+	var resultDir = filepath.Join(testDataDir, "golden/result")
+	doGoldenTests(t, resultDir, []test{
+		{name: "mkv", path: "fit-in/100x100/everybody-betray-me.mkv"},
+		{name: "mkv meta", path: "meta/everybody-betray-me.mkv"},
+		{name: "mp4", path: "fit-in/100x100/schizo_0.mp4"},
+		{name: "mp4 90", path: "fit-in/100x100/schizo_90.mp4"},
+		{name: "mp4 180", path: "fit-in/100x100/schizo_180.mp4"},
+		{name: "mp4 270", path: "fit-in/100x100/schizo_270.mp4"},
+		{name: "image", path: "fit-in/100x100/demo.png"},
+	}, WithDebug(true))
+}
+
+func doGoldenTests(t *testing.T, resultDir string, tests []test, opts ...Option) {
+	resStorage := filestorage.New(resultDir,
+		filestorage.WithSaveErrIfExists(true))
+	loader := filestorage.New(testDataDir)
+	loaders := []imagor.Loader{
+		loader,
+		loaderFunc(func(r *http.Request, image string) (blob *imagor.Blob, err error) {
+			image, _ = loader.Path(image)
+			return imagor.NewBlob(func() (reader io.ReadCloser, size int64, err error) {
+				// force read full file by 0 size
+				reader, err = os.Open(image)
+				return
+			}), nil
+		}),
+	}
+	for i, loader := range loaders {
+		app := imagor.New(
+			imagor.WithLoaders(loader),
+			imagor.WithUnsafe(true),
+			imagor.WithDebug(true),
+			imagor.WithLogger(zap.NewExample()),
+			imagor.WithProcessors(NewProcessor(opts...), vips.NewProcessor()),
+		)
+		require.NoError(t, app.Startup(context.Background()))
+		t.Cleanup(func() {
+			assert.NoError(t, app.Shutdown(context.Background()))
+		})
+		for _, tt := range tests {
+			t.Run(fmt.Sprintf("%s-%d", tt.name, i+1), func(t *testing.T) {
+				w := httptest.NewRecorder()
+				ctx, cancel := context.WithCancel(context.Background())
+				req := httptest.NewRequest(
+					http.MethodGet, fmt.Sprintf("/unsafe/%s", tt.path), nil).WithContext(ctx)
+				app.ServeHTTP(w, req)
+				cancel()
+				assert.Equal(t, 200, w.Code)
+				b := imagor.NewBlobFromBytes(w.Body.Bytes())
+				_ = resStorage.Put(context.Background(), tt.path, b)
+				path := filepath.Join(resultDir, imagorpath.Normalize(tt.path, nil))
+
+				bc := imagor.NewBlobFromFile(path)
+				buf, err := bc.ReadAll()
+				require.NoError(t, err)
+				if reflect.DeepEqual(buf, w.Body.Bytes()) {
+					return
+				}
+				img1, err := vips.LoadImageFromFile(path, nil)
+				require.NoError(t, err)
+				img2, err := vips.LoadImageFromBuffer(w.Body.Bytes(), nil)
+				require.NoError(t, err)
+				require.Equal(t, img1.Width(), img2.Width(), "width mismatch")
+				require.Equal(t, img1.Height(), img2.Height(), "height mismatch")
+				buf1, err := img1.ExportWebp(nil)
+				require.NoError(t, err)
+				buf2, err := img2.ExportWebp(nil)
+				require.NoError(t, err)
+				require.True(t, reflect.DeepEqual(buf1, buf2), "image mismatch")
+			})
+		}
+
+	}
+
+}
+
+type loaderFunc func(r *http.Request, image string) (blob *imagor.Blob, err error)
+
+func (f loaderFunc) Get(r *http.Request, image string) (*imagor.Blob, error) {
+	return f(r, image)
+}
diff --git a/testdata/golden/result/fit-in/100x100/demo.png b/testdata/golden/result/fit-in/100x100/demo.png
new file mode 100644
index 0000000..a22b015
Binary files /dev/null and b/testdata/golden/result/fit-in/100x100/demo.png differ
diff --git a/testdata/golden/result/fit-in/100x100/everybody-betray-me.mkv b/testdata/golden/result/fit-in/100x100/everybody-betray-me.mkv
new file mode 100644
index 0000000..d7eef4c
Binary files /dev/null and b/testdata/golden/result/fit-in/100x100/everybody-betray-me.mkv differ
diff --git a/testdata/golden/result/fit-in/100x100/schizo_0.mp4 b/testdata/golden/result/fit-in/100x100/schizo_0.mp4
new file mode 100644
index 0000000..30a6269
Binary files /dev/null and b/testdata/golden/result/fit-in/100x100/schizo_0.mp4 differ
diff --git a/testdata/golden/result/fit-in/100x100/schizo_180.mp4 b/testdata/golden/result/fit-in/100x100/schizo_180.mp4
new file mode 100644
index 0000000..79613a9
Binary files /dev/null and b/testdata/golden/result/fit-in/100x100/schizo_180.mp4 differ
diff --git a/testdata/golden/result/fit-in/100x100/schizo_270.mp4 b/testdata/golden/result/fit-in/100x100/schizo_270.mp4
new file mode 100644
index 0000000..5595748
Binary files /dev/null and b/testdata/golden/result/fit-in/100x100/schizo_270.mp4 differ
diff --git a/testdata/golden/result/fit-in/100x100/schizo_90.mp4 b/testdata/golden/result/fit-in/100x100/schizo_90.mp4
new file mode 100644
index 0000000..09676d2
Binary files /dev/null and b/testdata/golden/result/fit-in/100x100/schizo_90.mp4 differ
diff --git a/testdata/golden/result/meta/everybody-betray-me.mkv b/testdata/golden/result/meta/everybody-betray-me.mkv
new file mode 100644
index 0000000..d64a578
--- /dev/null
+++ b/testdata/golden/result/meta/everybody-betray-me.mkv
@@ -0,0 +1 @@
+{"orientation":1,"duration":7407000000,"width":640,"height":480,"has_video":true,"has_audio":true,"has_alpha":false}
\ No newline at end of file