diff --git a/.dockerignore b/.dockerignore
index af42053..0080de0 100644
--- a/.dockerignore
+++ b/.dockerignore
@@ -1,5 +1,4 @@
 *.tzst
-*.tar
 /buildimage
 /dockerdeps
 /tmp
diff --git a/.gitignore b/.gitignore
index 32c0ff9..29bece0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,8 +1,8 @@
 mfer/*.pb.go
 /mfer.cmd
-vendor
 /tmp
 *.tmp
 *.docker.tzst
 *.tzst
 /builddeps/modcache.tar
+/vendor
diff --git a/Dockerfile b/Dockerfile
index 501c442..d8ba0b3 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,18 +1,11 @@
 ################################################################################
 #2345678911234567892123456789312345678941234567895123456789612345678971234567898
 ################################################################################
-FROM sneak/builder:main AS builder
-ENV GOPATH /go
+FROM sneak/builder:14e59af AS builder
 ENV DEBIAN_FRONTEND noninteractive
 WORKDIR /build
-COPY ./go.mod ./go.sum .
-RUN \
-    go mod download -x
-################################################################################
-#### caching phase done
-################################################################################
-WORKDIR /build
 COPY ./Makefile ./.golangci.yml ./go.mod ./go.sum .
+COPY ./vendor.tar /build/vendor.tar
 COPY ./internal ./internal
 COPY ./bin/gitrev.sh ./bin/gitrev.sh
 COPY ./mfer ./mfer
@@ -22,6 +15,7 @@ ARG GITREV unknown
 RUN \
     cd mfer && go generate . && cd .. && \
     GOPACKAGESDEBUG=true golangci-lint run ./... && \
+    tar xf vendor.tar && rm vendor.tar && \
     make mfer.cmd
 RUN go mod vendor && tar -c . | zstdmt -19 > /src.tzst
 ################################################################################
diff --git a/Makefile b/Makefile
index 76300a7..ad0e696 100644
--- a/Makefile
+++ b/Makefile
@@ -58,7 +58,7 @@ lint:
 
 docker: sneak-mfer.$(ARCH).docker.tzst
 
-sneak-mfer.$(ARCH).docker.tzst: $(SOURCEFILES)
+sneak-mfer.$(ARCH).docker.tzst: $(SOURCEFILES) vendor.tar
 	docker build --progress plain --build-arg GITREV=$(GITREV_BUILD) -t sneak/mfer .
 	docker save sneak/mfer | pv | zstdmt -19 > $@
 	du -sh $@
@@ -66,3 +66,8 @@ sneak-mfer.$(ARCH).docker.tzst: $(SOURCEFILES)
 godoc:
 	open http://127.0.0.1:6060
 	godoc -http=:6060
+
+vendor.tar: go.mod go.sum
+	go mod vendor
+	tar -c vendor > $@
+	rm -rf vendor
diff --git a/buildimage/Dockerfile b/buildimage/Dockerfile
deleted file mode 100644
index dea8624..0000000
--- a/buildimage/Dockerfile
+++ /dev/null
@@ -1,21 +0,0 @@
-## build image:
-FROM golang:1.19.3-bullseye AS builder
-
-ENV DEBIAN_FRONTEND noninteractive
-RUN apt update && apt install -y make bzip2 curl unzip
-RUN mkdir -p /build
-WORKDIR /build
-
-# install newer protoc
-RUN wget https://github.com/protocolbuffers/protobuf/releases/download/v21.10/protoc-21.10-linux-aarch_64.zip && \
-    unzip *.zip -d /usr/local && rm -v *.zip && protoc --version
-
-RUN go install -v google.golang.org/protobuf/cmd/protoc-gen-go@v1.28.1
-
-RUN go env
-
-COPY ./go.mod .
-COPY ./go.sum .
-
-RUN --mount=type=cache,target=/go/pkg go mod download -x
-RUN rm -rfv /var/cache/* /var/tmp/*
diff --git a/internal/bork/error.go b/internal/bork/error.go
index 83a99ae..6ead94d 100644
--- a/internal/bork/error.go
+++ b/internal/bork/error.go
@@ -5,9 +5,11 @@ import (
 	"fmt"
 )
 
-var ErrMissingMagic = errors.New("missing magic bytes in file")
-var ErrFileTruncated = errors.New("file/stream is truncated abnormally")
+var (
+	ErrMissingMagic  = errors.New("missing magic bytes in file")
+	ErrFileTruncated = errors.New("file/stream is truncated abnormally")
+)
 
 func Newf(format string, args ...interface{}) error {
-	return errors.New(fmt.Sprintf(format, args...))
+	return fmt.Errorf(format, args...)
 }
diff --git a/internal/bork/error_test.go b/internal/bork/error_test.go
new file mode 100644
index 0000000..f98318f
--- /dev/null
+++ b/internal/bork/error_test.go
@@ -0,0 +1,11 @@
+package bork
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestBuild(t *testing.T) {
+	assert.NotNil(t, ErrMissingMagic)
+}
diff --git a/internal/cli/misc.go b/internal/cli/misc.go
deleted file mode 100644
index b4bc086..0000000
--- a/internal/cli/misc.go
+++ /dev/null
@@ -1,32 +0,0 @@
-package cli
-
-import "fmt"
-
-// FIXME make this write to a bytes.Buffer with fprintf
-func DumpByteSlice(b []byte) {
-	var a [16]byte
-	n := (len(b) + 15) &^ 15
-	for i := 0; i < n; i++ {
-		if i%16 == 0 {
-			fmt.Printf("%4d", i)
-		}
-		if i%8 == 0 {
-			fmt.Print(" ")
-		}
-		if i < len(b) {
-			fmt.Printf(" %02X", b[i])
-		} else {
-			fmt.Print("   ")
-		}
-		if i >= len(b) {
-			a[i%16] = ' '
-		} else if b[i] < 32 || b[i] > 126 {
-			a[i%16] = '.'
-		} else {
-			a[i%16] = b[i]
-		}
-		if i%16 == 15 {
-			fmt.Printf("  %s\n", string(a[:]))
-		}
-	}
-}
diff --git a/internal/log/log_test.go b/internal/log/log_test.go
new file mode 100644
index 0000000..b36c642
--- /dev/null
+++ b/internal/log/log_test.go
@@ -0,0 +1,12 @@
+package log
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestBuild(t *testing.T) {
+	Init()
+	assert.True(t, true)
+}
diff --git a/mfer/example_test.go b/mfer/example_test.go
index 5d2be5e..af4164b 100644
--- a/mfer/example_test.go
+++ b/mfer/example_test.go
@@ -9,7 +9,6 @@ import (
 )
 
 func TestAPIExample(t *testing.T) {
-
 	// read from filesystem
 	m, err := NewFromFS(&ManifestScanOptions{
 		IgnoreDotfiles: true,
diff --git a/mfer/mfer_test.go b/mfer/mfer_test.go
index 5db6e70..18858a6 100644
--- a/mfer/mfer_test.go
+++ b/mfer/mfer_test.go
@@ -32,7 +32,7 @@ func init() {
 	af.WriteFile("/.hidden/hello2.txt", []byte("hello world\n"), 0o755)
 
 	big.MkdirAll("/home/user/Library", 0o755)
-	for i, _ := range [25]int{} {
+	for i := range [25]int{} {
 		big.WriteFile(fmt.Sprintf("/home/user/Library/hello%d.txt", i), []byte("hello world\n"), 0o755)
 	}
 }