@@ -751,7 +751,7 @@ func TestRunEnvironment(t *testing.T) {

 	}

 	sort.Strings(goodEnv)

 	if len(goodEnv) != len(actualEnv) {

-		t.Fatalf("Wrong environment: should be %d variables, not: '%s'\n", len(goodEnv), strings.Join(actualEnv, ", "))

+		t.Fatalf("Wrong environment: should be %d variables, not: %q\n", len(goodEnv), strings.Join(actualEnv, ", "))

 	}

 	for i := range goodEnv {

 		if actualEnv[i] != goodEnv[i] {

@@ -1168,7 +1168,7 @@ func TestRunModeHostname(t *testing.T) {

 	}

 	if actual := strings.Trim(out, "\r\n"); actual != "testhostname" {

-		t.Fatalf("expected 'testhostname', but says: '%s'", actual)

+		t.Fatalf("expected 'testhostname', but says: %q", actual)

 	}

 	cmd = exec.Command(dockerBinary, "run", "--net=host", "busybox", "cat", "/etc/hostname")

@@ -1182,7 +1182,7 @@ func TestRunModeHostname(t *testing.T) {

 		t.Fatal(err)

 	}

 	if actual := strings.Trim(out, "\r\n"); actual != hostname {

-		t.Fatalf("expected '%s', but says: '%s'", hostname, actual)

+		t.Fatalf("expected %q, but says: '%s'", hostname, actual)

 	}

 	deleteAllContainers()

@@ -1196,7 +1196,7 @@ func TestRunRootWorkdir(t *testing.T) {

 		t.Fatal(s, err)

 	}

 	if s != "/\n" {

-		t.Fatalf("pwd returned '%s' (expected /\\n)", s)

+		t.Fatalf("pwd returned %q (expected /\\n)", s)

 	}

 	deleteAllContainers()

@@ -1297,7 +1297,7 @@ func TestRunDnsOptions(t *testing.T) {

 	actual := strings.Replace(strings.Trim(out, "\r\n"), "\n", " ", -1)

 	if actual != "nameserver 127.0.0.1 search mydomain" {

-		t.Fatalf("expected 'nameserver 127.0.0.1 search mydomain', but says: '%s'", actual)

+		t.Fatalf("expected 'nameserver 127.0.0.1 search mydomain', but says: %q", actual)

 	}

 	cmd = exec.Command(dockerBinary, "run", "--dns=127.0.0.1", "--dns-search=.", "busybox", "cat", "/etc/resolv.conf")

@@ -1309,61 +1309,101 @@ func TestRunDnsOptions(t *testing.T) {

 	actual = strings.Replace(strings.Trim(strings.Trim(out, "\r\n"), " "), "\n", " ", -1)

 	if actual != "nameserver 127.0.0.1" {

-		t.Fatalf("expected 'nameserver 127.0.0.1', but says: '%s'", actual)

+		t.Fatalf("expected 'nameserver 127.0.0.1', but says: %q", actual)

 	}

 	logDone("run - dns options")

 }

 func TestRunDnsOptionsBasedOnHostResolvConf(t *testing.T) {

-	resolvConf, err := ioutil.ReadFile("/etc/resolv.conf")

+	var out string

+

+	origResolvConf, err := ioutil.ReadFile("/etc/resolv.conf")

 	if os.IsNotExist(err) {

 		t.Fatalf("/etc/resolv.conf does not exist")

 	}

-	hostNamservers := resolvconf.GetNameservers(resolvConf)

-	hostSearch := resolvconf.GetSearchDomains(resolvConf)

+	hostNamservers := resolvconf.GetNameservers(origResolvConf)

+	hostSearch := resolvconf.GetSearchDomains(origResolvConf)

 	cmd := exec.Command(dockerBinary, "run", "--dns=127.0.0.1", "busybox", "cat", "/etc/resolv.conf")

-	out, _, err := runCommandWithOutput(cmd)

-	if err != nil {

+	if out, _, err = runCommandWithOutput(cmd); err != nil {

 		t.Fatal(err, out)

 	}

 	if actualNameservers := resolvconf.GetNameservers([]byte(out)); string(actualNameservers[0]) != "127.0.0.1" {

-		t.Fatalf("expected '127.0.0.1', but says: '%s'", string(actualNameservers[0]))

+		t.Fatalf("expected '127.0.0.1', but says: %q", string(actualNameservers[0]))

 	}

 	actualSearch := resolvconf.GetSearchDomains([]byte(out))

 	if len(actualSearch) != len(hostSearch) {

-		t.Fatalf("expected '%s' search domain(s), but it has: '%s'", len(hostSearch), len(actualSearch))

+		t.Fatalf("expected %q search domain(s), but it has: '%s'", len(hostSearch), len(actualSearch))

 	}

 	for i := range actualSearch {

 		if actualSearch[i] != hostSearch[i] {

-			t.Fatalf("expected '%s' domain, but says: '%s'", actualSearch[i], hostSearch[i])

+			t.Fatalf("expected %q domain, but says: '%s'", actualSearch[i], hostSearch[i])

 		}

 	}

 	cmd = exec.Command(dockerBinary, "run", "--dns-search=mydomain", "busybox", "cat", "/etc/resolv.conf")

-	out, _, err = runCommandWithOutput(cmd)

-	if err != nil {

+	if out, _, err = runCommandWithOutput(cmd); err != nil {

 		t.Fatal(err, out)

 	}

 	actualNameservers := resolvconf.GetNameservers([]byte(out))

 	if len(actualNameservers) != len(hostNamservers) {

-		t.Fatalf("expected '%s' nameserver(s), but it has: '%s'", len(hostNamservers), len(actualNameservers))

+		t.Fatalf("expected %q nameserver(s), but it has: '%s'", len(hostNamservers), len(actualNameservers))

 	}

 	for i := range actualNameservers {

 		if actualNameservers[i] != hostNamservers[i] {

-			t.Fatalf("expected '%s' nameserver, but says: '%s'", actualNameservers[i], hostNamservers[i])

+			t.Fatalf("expected %q nameserver, but says: '%s'", actualNameservers[i], hostNamservers[i])

 		}

 	}

 	if actualSearch = resolvconf.GetSearchDomains([]byte(out)); string(actualSearch[0]) != "mydomain" {

-		t.Fatalf("expected 'mydomain', but says: '%s'", string(actualSearch[0]))

+		t.Fatalf("expected 'mydomain', but says: %q", string(actualSearch[0]))

+	}

+

+	// test with file

+	tmpResolvConf := []byte("search example.com\nnameserver 12.34.56.78\nnameserver 127.0.0.1")

+	if err := ioutil.WriteFile("/etc/resolv.conf", tmpResolvConf, 0644); err != nil {

+		t.Fatal(err)

+	}

+	// put the old resolvconf back

+	defer func() {

+		if err := ioutil.WriteFile("/etc/resolv.conf", origResolvConf, 0644); err != nil {

+			t.Fatal(err)

+		}

+	}()

+

+	resolvConf, err := ioutil.ReadFile("/etc/resolv.conf")

+	if os.IsNotExist(err) {

+		t.Fatalf("/etc/resolv.conf does not exist")

+	}

+

+	hostNamservers = resolvconf.GetNameservers(resolvConf)

+	hostSearch = resolvconf.GetSearchDomains(resolvConf)

+

+	cmd = exec.Command(dockerBinary, "run", "busybox", "cat", "/etc/resolv.conf")

+

+	if out, _, err = runCommandWithOutput(cmd); err != nil {

+		t.Fatal(err, out)

+	}

+

+	if actualNameservers = resolvconf.GetNameservers([]byte(out)); string(actualNameservers[0]) != "12.34.56.78" || len(actualNameservers) != 1 {

+		t.Fatalf("expected '12.34.56.78', but has: %v", actualNameservers)

+	}

+

+	actualSearch = resolvconf.GetSearchDomains([]byte(out))

+	if len(actualSearch) != len(hostSearch) {

+		t.Fatalf("expected %q search domain(s), but it has: %q", len(hostSearch), len(actualSearch))

+	}

+	for i := range actualSearch {

+		if actualSearch[i] != hostSearch[i] {

+			t.Fatalf("expected %q domain, but says: '%s'", actualSearch[i], hostSearch[i])

+		}

 	}

 	deleteAllContainers()

@@ -1382,7 +1422,7 @@ func TestRunAddHost(t *testing.T) {

 	actual := strings.Trim(out, "\r\n")

 	if actual != "86.75.30.9\textra" {

-		t.Fatalf("expected '86.75.30.9\textra', but says: '%s'", actual)

+		t.Fatalf("expected '86.75.30.9\textra', but says: %q", actual)

 	}

 	logDone("run - add-host option")

@@ -1989,7 +2029,7 @@ func TestRunCidFileCleanupIfEmpty(t *testing.T) {

 	}

 	if _, err := os.Stat(tmpCidFile); err == nil {

-		t.Fatalf("empty CIDFile '%s' should've been deleted", tmpCidFile)

+		t.Fatalf("empty CIDFile %q should've been deleted", tmpCidFile)

 	}

 	deleteAllContainers()

 	logDone("run - cleanup empty cidfile on fail")

@@ -2017,7 +2057,7 @@ func TestRunCidFileCheckIDLength(t *testing.T) {

 	}

 	cid := string(buffer)

 	if len(cid) != 64 {

-		t.Fatalf("--cidfile should be a long id, not '%s'", id)

+		t.Fatalf("--cidfile should be a long id, not %q", id)

 	}

 	if cid != id {

 		t.Fatalf("cid must be equal to %s, got %s", id, cid)