diff --git a/cmd/prometheus/main_test.go b/cmd/prometheus/main_test.go
index e82e55bc3..1cf97f8eb 100644
--- a/cmd/prometheus/main_test.go
+++ b/cmd/prometheus/main_test.go
@@ -172,7 +172,7 @@ func TestFailedStartupExitCode(t *testing.T) {
 
 	prom := exec.Command(promPath, "--config.file="+fakeInputFile)
 	err := prom.Run()
-	testutil.NotOk(t, err, "")
+	testutil.NotOk(t, err)
 
 	if exitError, ok := err.(*exec.ExitError); ok {
 		status := exitError.Sys().(syscall.WaitStatus)
@@ -275,7 +275,7 @@ func TestWALSegmentSizeBounds(t *testing.T) {
 		}
 
 		err = prom.Wait()
-		testutil.NotOk(t, err, "")
+		testutil.NotOk(t, err)
 		if exitError, ok := err.(*exec.ExitError); ok {
 			status := exitError.Sys().(syscall.WaitStatus)
 			testutil.Equals(t, expectedExitStatus, status.ExitStatus())
diff --git a/config/config_test.go b/config/config_test.go
index 03150dace..9f744db7a 100644
--- a/config/config_test.go
+++ b/config/config_test.go
@@ -897,7 +897,7 @@ func TestBadStaticConfigsJSON(t *testing.T) {
 	testutil.Ok(t, err)
 	var tg targetgroup.Group
 	err = json.Unmarshal(content, &tg)
-	testutil.NotOk(t, err, "")
+	testutil.NotOk(t, err)
 }
 
 func TestBadStaticConfigsYML(t *testing.T) {
@@ -905,7 +905,7 @@ func TestBadStaticConfigsYML(t *testing.T) {
 	testutil.Ok(t, err)
 	var tg targetgroup.Group
 	err = yaml.UnmarshalStrict(content, &tg)
-	testutil.NotOk(t, err, "")
+	testutil.NotOk(t, err)
 }
 
 func TestEmptyConfig(t *testing.T) {
diff --git a/discovery/openstack/hypervisor_test.go b/discovery/openstack/hypervisor_test.go
index 1e4463892..c4acbb27b 100644
--- a/discovery/openstack/hypervisor_test.go
+++ b/discovery/openstack/hypervisor_test.go
@@ -92,7 +92,7 @@ func TestOpenstackSDHypervisorRefreshWithDoneContext(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	cancel()
 	_, err := hypervisor.refresh(ctx)
-	testutil.NotOk(t, err, "")
+	testutil.NotOk(t, err)
 	testutil.Assert(t, strings.Contains(err.Error(), context.Canceled.Error()), "%q doesn't contain %q", err, context.Canceled)
 
 	mock.TearDownSuite()
diff --git a/discovery/openstack/instance_test.go b/discovery/openstack/instance_test.go
index 7e2869118..a6ec1cd39 100644
--- a/discovery/openstack/instance_test.go
+++ b/discovery/openstack/instance_test.go
@@ -140,7 +140,7 @@ func TestOpenstackSDInstanceRefreshWithDoneContext(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	cancel()
 	_, err := hypervisor.refresh(ctx)
-	testutil.NotOk(t, err, "")
+	testutil.NotOk(t, err)
 	testutil.Assert(t, strings.Contains(err.Error(), context.Canceled.Error()), "%q doesn't contain %q", err, context.Canceled)
 
 	mock.TearDownSuite()
diff --git a/discovery/triton/triton_test.go b/discovery/triton/triton_test.go
index 3050d36ff..534fa494c 100644
--- a/discovery/triton/triton_test.go
+++ b/discovery/triton/triton_test.go
@@ -85,7 +85,7 @@ func TestTritonSDNew(t *testing.T) {
 
 func TestTritonSDNewBadConfig(t *testing.T) {
 	td, err := newTritonDiscovery(badconf)
-	testutil.NotOk(t, err, "")
+	testutil.NotOk(t, err)
 	testutil.Assert(t, td == nil, "")
 }
 
@@ -140,7 +140,7 @@ func TestTritonSDRefreshNoServer(t *testing.T) {
 	)
 
 	_, err := td.refresh(context.Background())
-	testutil.NotOk(t, err, "")
+	testutil.NotOk(t, err)
 	testutil.Equals(t, strings.Contains(err.Error(), "an error occurred when requesting targets from the discovery endpoint"), true)
 }
 
@@ -152,7 +152,7 @@ func TestTritonSDRefreshCancelled(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	cancel()
 	_, err := td.refresh(ctx)
-	testutil.NotOk(t, err, "")
+	testutil.NotOk(t, err)
 	testutil.Equals(t, strings.Contains(err.Error(), context.Canceled.Error()), true)
 }
 
diff --git a/pkg/textparse/promparse_test.go b/pkg/textparse/promparse_test.go
index 3f1d7b52f..7bfa36fc0 100644
--- a/pkg/textparse/promparse_test.go
+++ b/pkg/textparse/promparse_test.go
@@ -257,7 +257,7 @@ func TestPromParseErrors(t *testing.T) {
 		for err == nil {
 			_, err = p.Next()
 		}
-		testutil.NotOk(t, err, "")
+		testutil.NotOk(t, err)
 		testutil.Equals(t, c.err, err.Error(), "test %d", i)
 	}
 }
@@ -313,7 +313,7 @@ func TestPromNullByteHandling(t *testing.T) {
 			continue
 		}
 
-		testutil.NotOk(t, err, "")
+		testutil.NotOk(t, err)
 		testutil.Equals(t, c.err, err.Error(), "test %d", i)
 	}
 }
diff --git a/tsdb/block_test.go b/tsdb/block_test.go
index e9389e99a..a7a159483 100644
--- a/tsdb/block_test.go
+++ b/tsdb/block_test.go
@@ -28,8 +28,8 @@ import (
 	"github.com/go-kit/kit/log"
 	"github.com/prometheus/prometheus/tsdb/chunks"
 	"github.com/prometheus/prometheus/tsdb/labels"
-	"github.com/prometheus/prometheus/tsdb/testutil"
 	"github.com/prometheus/prometheus/tsdb/tsdbutil"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 // In Prometheus 2.1.0 we had a bug where the meta.json version was falsely bumped
diff --git a/tsdb/checkpoint_test.go b/tsdb/checkpoint_test.go
index 87753a79e..2fd4bf373 100644
--- a/tsdb/checkpoint_test.go
+++ b/tsdb/checkpoint_test.go
@@ -25,8 +25,8 @@ import (
 	"github.com/pkg/errors"
 	"github.com/prometheus/prometheus/tsdb/fileutil"
 	"github.com/prometheus/prometheus/tsdb/labels"
-	"github.com/prometheus/prometheus/tsdb/testutil"
 	"github.com/prometheus/prometheus/tsdb/wal"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 func TestLastCheckpoint(t *testing.T) {
diff --git a/tsdb/chunkenc/chunk_test.go b/tsdb/chunkenc/chunk_test.go
index 720572603..bd344882a 100644
--- a/tsdb/chunkenc/chunk_test.go
+++ b/tsdb/chunkenc/chunk_test.go
@@ -20,7 +20,7 @@ import (
 	"reflect"
 	"testing"
 
-	"github.com/prometheus/prometheus/tsdb/testutil"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 type pair struct {
diff --git a/tsdb/chunks/chunks_test.go b/tsdb/chunks/chunks_test.go
index 0454ea951..d9d952457 100644
--- a/tsdb/chunks/chunks_test.go
+++ b/tsdb/chunks/chunks_test.go
@@ -16,7 +16,7 @@ package chunks
 import (
 	"testing"
 
-	"github.com/prometheus/prometheus/tsdb/testutil"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 func TestReaderWithInvalidBuffer(t *testing.T) {
diff --git a/tsdb/cmd/tsdb/main.go b/tsdb/cmd/tsdb/main.go
index 005adb2dd..9acc80ad7 100644
--- a/tsdb/cmd/tsdb/main.go
+++ b/tsdb/cmd/tsdb/main.go
@@ -36,7 +36,7 @@ import (
 	"github.com/prometheus/prometheus/tsdb/chunks"
 	tsdb_errors "github.com/prometheus/prometheus/tsdb/errors"
 	"github.com/prometheus/prometheus/tsdb/labels"
-	"gopkg.in/alecthomas/kingpin.v2"
+	kingpin "gopkg.in/alecthomas/kingpin.v2"
 )
 
 func main() {
diff --git a/tsdb/compact_test.go b/tsdb/compact_test.go
index 7f113b39a..3b56cacd2 100644
--- a/tsdb/compact_test.go
+++ b/tsdb/compact_test.go
@@ -30,7 +30,7 @@ import (
 	"github.com/prometheus/prometheus/tsdb/chunks"
 	"github.com/prometheus/prometheus/tsdb/fileutil"
 	"github.com/prometheus/prometheus/tsdb/labels"
-	"github.com/prometheus/prometheus/tsdb/testutil"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 func TestSplitByRange(t *testing.T) {
diff --git a/tsdb/db_test.go b/tsdb/db_test.go
index 79c37d335..d8e94215b 100644
--- a/tsdb/db_test.go
+++ b/tsdb/db_test.go
@@ -33,9 +33,9 @@ import (
 	"github.com/prometheus/prometheus/tsdb/chunks"
 	"github.com/prometheus/prometheus/tsdb/index"
 	"github.com/prometheus/prometheus/tsdb/labels"
-	"github.com/prometheus/prometheus/tsdb/testutil"
 	"github.com/prometheus/prometheus/tsdb/tsdbutil"
 	"github.com/prometheus/prometheus/tsdb/wal"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 func openTestDB(t testing.TB, opts *Options) (db *DB, close func()) {
diff --git a/tsdb/fileutil/flock_test.go b/tsdb/fileutil/flock_test.go
index a5c880763..f9cbbcf2b 100644
--- a/tsdb/fileutil/flock_test.go
+++ b/tsdb/fileutil/flock_test.go
@@ -18,7 +18,7 @@ import (
 	"path/filepath"
 	"testing"
 
-	"github.com/prometheus/prometheus/tsdb/testutil"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 func TestLocking(t *testing.T) {
diff --git a/tsdb/head_bench_test.go b/tsdb/head_bench_test.go
index f8c78cf8d..85542d1ef 100644
--- a/tsdb/head_bench_test.go
+++ b/tsdb/head_bench_test.go
@@ -19,7 +19,7 @@ import (
 	"testing"
 
 	"github.com/prometheus/prometheus/tsdb/labels"
-	"github.com/prometheus/prometheus/tsdb/testutil"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 func BenchmarkHeadStripeSeriesCreate(b *testing.B) {
diff --git a/tsdb/head_test.go b/tsdb/head_test.go
index 3551996e1..acfc82a5e 100644
--- a/tsdb/head_test.go
+++ b/tsdb/head_test.go
@@ -30,9 +30,9 @@ import (
 	"github.com/prometheus/prometheus/tsdb/chunks"
 	"github.com/prometheus/prometheus/tsdb/index"
 	"github.com/prometheus/prometheus/tsdb/labels"
-	"github.com/prometheus/prometheus/tsdb/testutil"
 	"github.com/prometheus/prometheus/tsdb/tsdbutil"
 	"github.com/prometheus/prometheus/tsdb/wal"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 func BenchmarkCreateSeries(b *testing.B) {
diff --git a/tsdb/index/index_test.go b/tsdb/index/index_test.go
index 28622cc90..cfb00c333 100644
--- a/tsdb/index/index_test.go
+++ b/tsdb/index/index_test.go
@@ -26,7 +26,7 @@ import (
 	"github.com/prometheus/prometheus/tsdb/chunks"
 	"github.com/prometheus/prometheus/tsdb/encoding"
 	"github.com/prometheus/prometheus/tsdb/labels"
-	"github.com/prometheus/prometheus/tsdb/testutil"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 type series struct {
diff --git a/tsdb/index/postings_test.go b/tsdb/index/postings_test.go
index 42dc6b3f3..eedf59097 100644
--- a/tsdb/index/postings_test.go
+++ b/tsdb/index/postings_test.go
@@ -20,7 +20,7 @@ import (
 	"sort"
 	"testing"
 
-	"github.com/prometheus/prometheus/tsdb/testutil"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 func TestMemPostings_addFor(t *testing.T) {
diff --git a/tsdb/labels/labels_test.go b/tsdb/labels/labels_test.go
index fbf63a0de..c2599781e 100644
--- a/tsdb/labels/labels_test.go
+++ b/tsdb/labels/labels_test.go
@@ -20,7 +20,7 @@ import (
 	"sort"
 	"testing"
 
-	"github.com/prometheus/prometheus/tsdb/testutil"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 func TestCompareAndEquals(t *testing.T) {
diff --git a/tsdb/querier_test.go b/tsdb/querier_test.go
index b9366ec4c..b76a3af5f 100644
--- a/tsdb/querier_test.go
+++ b/tsdb/querier_test.go
@@ -29,8 +29,8 @@ import (
 	"github.com/prometheus/prometheus/tsdb/chunks"
 	"github.com/prometheus/prometheus/tsdb/index"
 	"github.com/prometheus/prometheus/tsdb/labels"
-	"github.com/prometheus/prometheus/tsdb/testutil"
 	"github.com/prometheus/prometheus/tsdb/tsdbutil"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 type mockSeriesSet struct {
diff --git a/tsdb/record_test.go b/tsdb/record_test.go
index 7d948c7f4..482780c1c 100644
--- a/tsdb/record_test.go
+++ b/tsdb/record_test.go
@@ -20,7 +20,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/prometheus/prometheus/tsdb/encoding"
 	"github.com/prometheus/prometheus/tsdb/labels"
-	"github.com/prometheus/prometheus/tsdb/testutil"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 func TestRecord_EncodeDecode(t *testing.T) {
diff --git a/tsdb/repair_test.go b/tsdb/repair_test.go
index 3cb5d43de..c3a1d22b2 100644
--- a/tsdb/repair_test.go
+++ b/tsdb/repair_test.go
@@ -22,7 +22,7 @@ import (
 	"github.com/prometheus/prometheus/tsdb/fileutil"
 	"github.com/prometheus/prometheus/tsdb/index"
 	"github.com/prometheus/prometheus/tsdb/labels"
-	"github.com/prometheus/prometheus/tsdb/testutil"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 func TestRepairBadIndexVersion(t *testing.T) {
diff --git a/tsdb/testutil/directory.go b/tsdb/testutil/directory.go
deleted file mode 100644
index 5f1c31554..000000000
--- a/tsdb/testutil/directory.go
+++ /dev/null
@@ -1,182 +0,0 @@
-// Copyright 2013 The Prometheus 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 testutil
-
-import (
-	"crypto/sha256"
-	"io"
-	"io/ioutil"
-	"os"
-	"path/filepath"
-	"strconv"
-	"testing"
-)
-
-const (
-	// The base directory used for test emissions, which instructs the operating
-	// system to use the default temporary directory as the base or TMPDIR
-	// environment variable.
-	defaultDirectory = ""
-
-	// NilCloser is a no-op Closer.
-	NilCloser = nilCloser(true)
-
-	// The number of times that a TemporaryDirectory will retry its removal
-	temporaryDirectoryRemoveRetries = 2
-)
-
-type (
-	// Closer is the interface that wraps the Close method.
-	Closer interface {
-		// Close reaps the underlying directory and its children. The directory
-		// could be deleted by its users already.
-		Close()
-	}
-
-	nilCloser bool
-
-	// TemporaryDirectory models a closeable path for transient POSIX disk
-	// activities.
-	TemporaryDirectory interface {
-		Closer
-
-		// Path returns the underlying path for access.
-		Path() string
-	}
-
-	// temporaryDirectory is kept as a private type due to private fields and
-	// their interactions.
-	temporaryDirectory struct {
-		path   string
-		tester T
-	}
-
-	callbackCloser struct {
-		fn func()
-	}
-
-	// T implements the needed methods of testing.TB so that we do not need
-	// to actually import testing (which has the side effect of adding all
-	// the test flags, which we do not want in non-test binaries even if
-	// they make use of these utilities for some reason).
-	T interface {
-		Fatal(args ...interface{})
-		Fatalf(format string, args ...interface{})
-	}
-)
-
-func (c nilCloser) Close() {
-}
-
-func (c callbackCloser) Close() {
-	c.fn()
-}
-
-// NewCallbackCloser returns a Closer that calls the provided function upon
-// closing.
-func NewCallbackCloser(fn func()) Closer {
-	return &callbackCloser{
-		fn: fn,
-	}
-}
-
-func (t temporaryDirectory) Close() {
-	retries := temporaryDirectoryRemoveRetries
-	err := os.RemoveAll(t.path)
-	for err != nil && retries > 0 {
-		switch {
-		case os.IsNotExist(err):
-			err = nil
-		default:
-			retries--
-			err = os.RemoveAll(t.path)
-		}
-	}
-	if err != nil {
-		t.tester.Fatal(err)
-	}
-}
-
-func (t temporaryDirectory) Path() string {
-	return t.path
-}
-
-// NewTemporaryDirectory creates a new temporary directory for transient POSIX
-// activities.
-func NewTemporaryDirectory(name string, t T) (handler TemporaryDirectory) {
-	var (
-		directory string
-		err       error
-	)
-
-	directory, err = ioutil.TempDir(defaultDirectory, name)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	handler = temporaryDirectory{
-		path:   directory,
-		tester: t,
-	}
-
-	return
-}
-
-// DirSize returns the size in bytes of all files in a directory.
-func DirSize(t *testing.T, path string) int64 {
-	var size int64
-	err := filepath.Walk(path, func(_ string, info os.FileInfo, err error) error {
-		Ok(t, err)
-		if !info.IsDir() {
-			size += info.Size()
-		}
-		return nil
-	})
-	Ok(t, err)
-	return size
-}
-
-// DirHash returns a hash of all files attribites and their content within a directory.
-func DirHash(t *testing.T, path string) []byte {
-	hash := sha256.New()
-	err := filepath.Walk(path, func(path string, info os.FileInfo, err error) error {
-		Ok(t, err)
-
-		if info.IsDir() {
-			return nil
-		}
-		f, err := os.Open(path)
-		Ok(t, err)
-		defer f.Close()
-
-		_, err = io.Copy(hash, f)
-		Ok(t, err)
-
-		_, err = io.WriteString(hash, strconv.Itoa(int(info.Size())))
-		Ok(t, err)
-
-		_, err = io.WriteString(hash, info.Name())
-		Ok(t, err)
-
-		modTime, err := info.ModTime().GobEncode()
-		Ok(t, err)
-
-		_, err = io.WriteString(hash, string(modTime))
-		Ok(t, err)
-		return nil
-	})
-	Ok(t, err)
-
-	return hash.Sum(nil)
-}
diff --git a/tsdb/testutil/testutil.go b/tsdb/testutil/testutil.go
deleted file mode 100644
index 03784e7f2..000000000
--- a/tsdb/testutil/testutil.go
+++ /dev/null
@@ -1,87 +0,0 @@
-// The MIT License (MIT)
-
-// Copyright (c) 2014 Ben Johnson
-
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-
-// The above copyright notice and this permission notice shall be included in all
-// copies or substantial portions of the Software.
-
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-// SOFTWARE.
-
-package testutil
-
-import (
-	"fmt"
-	"path/filepath"
-	"reflect"
-	"runtime"
-	"testing"
-)
-
-// Assert fails the test if the condition is false.
-func Assert(tb testing.TB, condition bool, msg string, v ...interface{}) {
-	if !condition {
-		_, file, line, _ := runtime.Caller(1)
-		fmt.Printf("\033[31m%s:%d: "+msg+"\033[39m\n\n", append([]interface{}{filepath.Base(file), line}, v...)...)
-		tb.FailNow()
-	}
-}
-
-// Ok fails the test if an err is not nil.
-func Ok(tb testing.TB, err error) {
-	if err != nil {
-		_, file, line, _ := runtime.Caller(1)
-		fmt.Printf("\033[31m%s:%d: unexpected error: %s\033[39m\n\n", filepath.Base(file), line, err.Error())
-		tb.FailNow()
-	}
-}
-
-// NotOk fails the test if an err is nil.
-func NotOk(tb testing.TB, err error) {
-	if err == nil {
-		_, file, line, _ := runtime.Caller(1)
-		fmt.Printf("\033[31m%s:%d: expected error, got nothing \033[39m\n\n", filepath.Base(file), line)
-		tb.FailNow()
-	}
-}
-
-// Equals fails the test if exp is not equal to act.
-func Equals(tb testing.TB, exp, act interface{}, msgAndArgs ...interface{}) {
-	if !reflect.DeepEqual(exp, act) {
-		_, file, line, _ := runtime.Caller(1)
-		fmt.Printf("\033[31m%s:%d:%s\n\n\texp: %#v\n\n\tgot: %#v\033[39m\n\n", filepath.Base(file), line, formatMessage(msgAndArgs), exp, act)
-		tb.FailNow()
-	}
-}
-
-// NotEquals fails the test if exp is equal to act.
-func NotEquals(tb testing.TB, exp, act interface{}) {
-	if reflect.DeepEqual(exp, act) {
-		_, file, line, _ := runtime.Caller(1)
-		fmt.Printf("\033[31m%s:%d: Expected different exp and got\n\n\texp: %#v\n\n\tgot: %#v\033[39m\n\n", filepath.Base(file), line, exp, act)
-		tb.FailNow()
-	}
-}
-
-func formatMessage(msgAndArgs []interface{}) string {
-	if len(msgAndArgs) == 0 {
-		return ""
-	}
-
-	if msg, ok := msgAndArgs[0].(string); ok {
-		return fmt.Sprintf("\n\nmsg: "+msg, msgAndArgs[1:]...)
-	}
-	return ""
-}
diff --git a/tsdb/tombstones_test.go b/tsdb/tombstones_test.go
index 947aa98bf..e37721a98 100644
--- a/tsdb/tombstones_test.go
+++ b/tsdb/tombstones_test.go
@@ -22,7 +22,7 @@ import (
 	"time"
 
 	"github.com/go-kit/kit/log"
-	"github.com/prometheus/prometheus/tsdb/testutil"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 func TestWriteAndReadbackTombStones(t *testing.T) {
diff --git a/tsdb/tsdbutil/buffer_test.go b/tsdb/tsdbutil/buffer_test.go
index 7323a9e7d..b7954ea4e 100644
--- a/tsdb/tsdbutil/buffer_test.go
+++ b/tsdb/tsdbutil/buffer_test.go
@@ -18,7 +18,7 @@ import (
 	"sort"
 	"testing"
 
-	"github.com/prometheus/prometheus/tsdb/testutil"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 func TestSampleRing(t *testing.T) {
diff --git a/tsdb/wal/reader_test.go b/tsdb/wal/reader_test.go
index d9c74453a..eb858a780 100644
--- a/tsdb/wal/reader_test.go
+++ b/tsdb/wal/reader_test.go
@@ -31,7 +31,7 @@ import (
 
 	"github.com/go-kit/kit/log"
 	tsdb_errors "github.com/prometheus/prometheus/tsdb/errors"
-	"github.com/prometheus/prometheus/tsdb/testutil"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 type reader interface {
diff --git a/tsdb/wal/wal_test.go b/tsdb/wal/wal_test.go
index d99a96342..81a845fd4 100644
--- a/tsdb/wal/wal_test.go
+++ b/tsdb/wal/wal_test.go
@@ -24,7 +24,7 @@ import (
 	"testing"
 
 	client_testutil "github.com/prometheus/client_golang/prometheus/testutil"
-	"github.com/prometheus/prometheus/tsdb/testutil"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 // TestWALRepair_ReadingError ensures that a repair is run for an error
diff --git a/tsdb/wal_test.go b/tsdb/wal_test.go
index 5c8a7489d..71271ae5c 100644
--- a/tsdb/wal_test.go
+++ b/tsdb/wal_test.go
@@ -29,8 +29,8 @@ import (
 	"github.com/go-kit/kit/log"
 	"github.com/prometheus/prometheus/tsdb/fileutil"
 	"github.com/prometheus/prometheus/tsdb/labels"
-	"github.com/prometheus/prometheus/tsdb/testutil"
 	"github.com/prometheus/prometheus/tsdb/wal"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 func TestSegmentWAL_cut(t *testing.T) {
diff --git a/util/testutil/directory.go b/util/testutil/directory.go
index d3c9c926f..5f1c31554 100644
--- a/util/testutil/directory.go
+++ b/util/testutil/directory.go
@@ -14,8 +14,13 @@
 package testutil
 
 import (
+	"crypto/sha256"
+	"io"
 	"io/ioutil"
 	"os"
+	"path/filepath"
+	"strconv"
+	"testing"
 )
 
 const (
@@ -127,3 +132,51 @@ func NewTemporaryDirectory(name string, t T) (handler TemporaryDirectory) {
 
 	return
 }
+
+// DirSize returns the size in bytes of all files in a directory.
+func DirSize(t *testing.T, path string) int64 {
+	var size int64
+	err := filepath.Walk(path, func(_ string, info os.FileInfo, err error) error {
+		Ok(t, err)
+		if !info.IsDir() {
+			size += info.Size()
+		}
+		return nil
+	})
+	Ok(t, err)
+	return size
+}
+
+// DirHash returns a hash of all files attribites and their content within a directory.
+func DirHash(t *testing.T, path string) []byte {
+	hash := sha256.New()
+	err := filepath.Walk(path, func(path string, info os.FileInfo, err error) error {
+		Ok(t, err)
+
+		if info.IsDir() {
+			return nil
+		}
+		f, err := os.Open(path)
+		Ok(t, err)
+		defer f.Close()
+
+		_, err = io.Copy(hash, f)
+		Ok(t, err)
+
+		_, err = io.WriteString(hash, strconv.Itoa(int(info.Size())))
+		Ok(t, err)
+
+		_, err = io.WriteString(hash, info.Name())
+		Ok(t, err)
+
+		modTime, err := info.ModTime().GobEncode()
+		Ok(t, err)
+
+		_, err = io.WriteString(hash, string(modTime))
+		Ok(t, err)
+		return nil
+	})
+	Ok(t, err)
+
+	return hash.Sum(nil)
+}
diff --git a/tsdb/testutil/logging.go b/util/testutil/logging.go
similarity index 100%
rename from tsdb/testutil/logging.go
rename to util/testutil/logging.go
diff --git a/util/testutil/testing.go b/util/testutil/testing.go
index 52abce5bf..39b44e536 100644
--- a/util/testutil/testing.go
+++ b/util/testutil/testing.go
@@ -52,10 +52,11 @@ func Ok(tb TB, err error) {
 }
 
 // NotOk fails the test if an err is nil.
-func NotOk(tb TB, err error, format string, a ...interface{}) {
+func NotOk(tb TB, err error, a ...interface{}) {
 	tb.Helper()
 	if err == nil {
 		if len(a) != 0 {
+			format := a[0].(string)
 			tb.Fatalf("\033[31m"+format+": expected error, got none\033[39m", a...)
 		}
 		tb.Fatalf("\033[31mexpected error, got none\033[39m")
@@ -76,7 +77,7 @@ func formatMessage(msgAndArgs []interface{}) string {
 	}
 
 	if msg, ok := msgAndArgs[0].(string); ok {
-		return fmt.Sprintf("\nmsg: "+msg, msgAndArgs[1:]...)
+		return fmt.Sprintf("\n\nmsg: "+msg, msgAndArgs[1:]...)
 	}
 	return ""
 }