diff --git a/core/dns/storage.go b/core/dns/storage.go
new file mode 100644
index 000000000..0c8e68437
--- /dev/null
+++ b/core/dns/storage.go
@@ -0,0 +1,28 @@
+package dns
+
+import (
+	"path/filepath"
+
+	"github.com/miekg/coredns/core/assets"
+)
+
+var storage = Storage(assets.Path())
+
+// Storage is a root directory and facilitates
+// forming file paths derived from it.
+type Storage string
+
+// Zones gets the directory that stores zones data.
+func (s Storage) Zones() string {
+	return filepath.Join(string(s), "zones")
+}
+
+// Zone returns the path to the folder containing assets for domain.
+func (s Storage) Zone(domain string) string {
+	return filepath.Join(s.Zones(), domain)
+}
+
+// SecondaryZoneFile returns the path to domain's secondary zone file (when fetched).
+func (s Storage) SecondaryZoneFile(domain string) string {
+	return filepath.Join(s.Zone(domain), "db."+domain)
+}
diff --git a/core/dns/storage_test.go b/core/dns/storage_test.go
new file mode 100644
index 000000000..859435a15
--- /dev/null
+++ b/core/dns/storage_test.go
@@ -0,0 +1,20 @@
+package dns
+
+import (
+	"path/filepath"
+	"testing"
+)
+
+func TestStorage(t *testing.T) {
+	storage = Storage("./le_test")
+
+	if expected, actual := filepath.Join("le_test", "zones"), storage.Zones(); actual != expected {
+		t.Errorf("Expected Zones() to return '%s' but got '%s'", expected, actual)
+	}
+	if expected, actual := filepath.Join("le_test", "zones", "test.com"), storage.Zone("test.com"); actual != expected {
+		t.Errorf("Expected Site() to return '%s' but got '%s'", expected, actual)
+	}
+	if expected, actual := filepath.Join("le_test", "zones", "test.com", "db.test.com"), storage.SecondaryZoneFile("test.com"); actual != expected {
+		t.Errorf("Expected SecondaryZoneFile() to return '%s' but got '%s'", expected, actual)
+	}
+}
diff --git a/middleware/etcd/msg/service_test.go b/middleware/etcd/msg/service_test.go
new file mode 100644
index 000000000..0c19ba95b
--- /dev/null
+++ b/middleware/etcd/msg/service_test.go
@@ -0,0 +1,125 @@
+package msg
+
+import "testing"
+
+func TestSplit255(t *testing.T) {
+	xs := split255("abc")
+	if len(xs) != 1 && xs[0] != "abc" {
+		t.Errorf("Failure to split abc")
+	}
+	s := ""
+	for i := 0; i < 255; i++ {
+		s += "a"
+	}
+	xs = split255(s)
+	if len(xs) != 1 && xs[0] != s {
+		t.Errorf("failure to split 255 char long string")
+	}
+	s += "b"
+	xs = split255(s)
+	if len(xs) != 2 || xs[1] != "b" {
+		t.Errorf("failure to split 256 char long string: %d", len(xs))
+	}
+	for i := 0; i < 255; i++ {
+		s += "a"
+	}
+	xs = split255(s)
+	if len(xs) != 3 || xs[2] != "a" {
+		t.Errorf("failure to split 510 char long string: %d", len(xs))
+	}
+}
+
+func TestGroup(t *testing.T) {
+	// Key are in the wrong order, but for this test it does not matter.
+	sx := Group(
+		[]Service{
+			{Host: "127.0.0.1", Group: "g1", Key: "b/sub/dom1/skydns/test"},
+			{Host: "127.0.0.2", Group: "g2", Key: "a/dom1/skydns/test"},
+		},
+	)
+	// Expecting to return the shortest key with a Group attribute.
+	if len(sx) != 1 {
+		t.Fatalf("failure to group zeroth set: %v", sx)
+	}
+	if sx[0].Key != "a/dom1/skydns/test" {
+		t.Fatalf("failure to group zeroth set: %v, wrong Key", sx)
+	}
+
+	// Groups disagree, so we will not do anything.
+	sx = Group(
+		[]Service{
+			{Host: "server1", Group: "g1", Key: "region1/skydns/test"},
+			{Host: "server2", Group: "g2", Key: "region1/skydns/test"},
+		},
+	)
+	if len(sx) != 2 {
+		t.Fatalf("failure to group first set: %v", sx)
+	}
+
+	// Group is g1, include only the top-level one.
+	sx = Group(
+		[]Service{
+			{Host: "server1", Group: "g1", Key: "a/dom/region1/skydns/test"},
+			{Host: "server2", Group: "g2", Key: "a/subdom/dom/region1/skydns/test"},
+		},
+	)
+	if len(sx) != 1 {
+		t.Fatalf("failure to group second set: %v", sx)
+	}
+
+	// Groupless services must be included.
+	sx = Group(
+		[]Service{
+			{Host: "server1", Group: "g1", Key: "a/dom/region1/skydns/test"},
+			{Host: "server2", Group: "g2", Key: "a/subdom/dom/region1/skydns/test"},
+			{Host: "server2", Group: "", Key: "b/subdom/dom/region1/skydns/test"},
+		},
+	)
+	if len(sx) != 2 {
+		t.Fatalf("failure to group third set: %v", sx)
+	}
+
+	// Empty group on the highest level: include that one also.
+	sx = Group(
+		[]Service{
+			{Host: "server1", Group: "g1", Key: "a/dom/region1/skydns/test"},
+			{Host: "server1", Group: "", Key: "b/dom/region1/skydns/test"},
+			{Host: "server2", Group: "g2", Key: "a/subdom/dom/region1/skydns/test"},
+		},
+	)
+	if len(sx) != 2 {
+		t.Fatalf("failure to group fourth set: %v", sx)
+	}
+
+	// Empty group on the highest level: include that one also, and the rest.
+	sx = Group(
+		[]Service{
+			{Host: "server1", Group: "g5", Key: "a/dom/region1/skydns/test"},
+			{Host: "server1", Group: "", Key: "b/dom/region1/skydns/test"},
+			{Host: "server2", Group: "g5", Key: "a/subdom/dom/region1/skydns/test"},
+		},
+	)
+	if len(sx) != 3 {
+		t.Fatalf("failure to group fith set: %v", sx)
+	}
+
+	// One group.
+	sx = Group(
+		[]Service{
+			{Host: "server1", Group: "g6", Key: "a/dom/region1/skydns/test"},
+		},
+	)
+	if len(sx) != 1 {
+		t.Fatalf("failure to group sixth set: %v", sx)
+	}
+
+	// No group, once service
+	sx = Group(
+		[]Service{
+			{Host: "server1", Key: "a/dom/region1/skydns/test"},
+		},
+	)
+	if len(sx) != 1 {
+		t.Fatalf("failure to group seventh set: %v", sx)
+	}
+}
diff --git a/middleware/singleflight/singleflight_test.go b/middleware/singleflight/singleflight_test.go
new file mode 100644
index 000000000..47b4d3dc0
--- /dev/null
+++ b/middleware/singleflight/singleflight_test.go
@@ -0,0 +1,85 @@
+/*
+Copyright 2012 Google Inc.
+
+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 singleflight
+
+import (
+	"errors"
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+)
+
+func TestDo(t *testing.T) {
+	var g Group
+	v, err := g.Do("key", func() (interface{}, error) {
+		return "bar", nil
+	})
+	if got, want := fmt.Sprintf("%v (%T)", v, v), "bar (string)"; got != want {
+		t.Errorf("Do = %v; want %v", got, want)
+	}
+	if err != nil {
+		t.Errorf("Do error = %v", err)
+	}
+}
+
+func TestDoErr(t *testing.T) {
+	var g Group
+	someErr := errors.New("Some error")
+	v, err := g.Do("key", func() (interface{}, error) {
+		return nil, someErr
+	})
+	if err != someErr {
+		t.Errorf("Do error = %v; want someErr", err)
+	}
+	if v != nil {
+		t.Errorf("unexpected non-nil value %#v", v)
+	}
+}
+
+func TestDoDupSuppress(t *testing.T) {
+	var g Group
+	c := make(chan string)
+	var calls int32
+	fn := func() (interface{}, error) {
+		atomic.AddInt32(&calls, 1)
+		return <-c, nil
+	}
+
+	const n = 10
+	var wg sync.WaitGroup
+	for i := 0; i < n; i++ {
+		wg.Add(1)
+		go func() {
+			v, err := g.Do("key", fn)
+			if err != nil {
+				t.Errorf("Do error: %v", err)
+			}
+			if v.(string) != "bar" {
+				t.Errorf("got %q; want %q", v, "bar")
+			}
+			wg.Done()
+		}()
+	}
+	time.Sleep(100 * time.Millisecond) // let goroutines above block
+	c <- "bar"
+	wg.Wait()
+	if got := atomic.LoadInt32(&calls); got != 1 {
+		t.Errorf("number of calls = %d; want 1", got)
+	}
+}
diff --git a/middleware/test/file_test.go b/middleware/test/file_test.go
new file mode 100644
index 000000000..950ea7cff
--- /dev/null
+++ b/middleware/test/file_test.go
@@ -0,0 +1,11 @@
+package test
+
+import "testing"
+
+func TestTempFile(t *testing.T) {
+	_, f, e := TempFile(t, ".", "test")
+	if e != nil {
+		t.Fatalf("failed to create temp file: %s", e)
+	}
+	defer f()
+}
diff --git a/middleware/test/helpers_test.go b/middleware/test/helpers_test.go
new file mode 100644
index 000000000..1b4d95bbc
--- /dev/null
+++ b/middleware/test/helpers_test.go
@@ -0,0 +1,8 @@
+package test
+
+import "testing"
+
+func TestA(t *testing.T) {
+	// should not crash
+	A("miek.nl. IN A 127.0.0.1")
+}