Run tests in parallel (#478)

Create a small speedup running the tests:

PASS
ok  	github.com/miekg/coredns/test	10.329s

PASS
ok  	github.com/miekg/coredns/test	6.079s

Skip the etcd ones. Doing the middleware/*/*_test ones doesn't yield
any speedup as these are still done on a per directory basis.

test/auto_test.go

@@ -16,6 +16,7 @@ import (
 )
 
 func TestAuto(t *testing.T) {
+	t.Parallel()
 	tmpdir, err := ioutil.TempDir(os.TempDir(), "coredns")
 	if err != nil {
 		t.Fatal(err)
@@ -81,6 +82,7 @@ func TestAuto(t *testing.T) {
 }
 
 func TestAutoNonExistentZone(t *testing.T) {
+	t.Parallel()
 	tmpdir, err := ioutil.TempDir(os.TempDir(), "coredns")
 	if err != nil {
 		t.Fatal(err)
@@ -119,6 +121,7 @@ func TestAutoNonExistentZone(t *testing.T) {
 }
 
 func TestAutoAXFR(t *testing.T) {
+	t.Parallel()
 	log.SetOutput(ioutil.Discard)
 
 	tmpdir, err := ioutil.TempDir(os.TempDir(), "coredns")

test/cache_test.go

@@ -14,6 +14,7 @@ import (
 )
 
 func TestLookupCache(t *testing.T) {
+	t.Parallel()
 	// Start auth. CoreDNS holding the auth zone.
 	name, rm, err := test.TempFile(".", exampleOrg)
 	if err != nil {

test/ds_file_test.go

@@ -32,6 +32,7 @@ var dsTestCases = []mtest.Case{
 }
 
 func TestLookupDS(t *testing.T) {
+	t.Parallel()
 	name, rm, err := TempFile(".", miekNL)
 	if err != nil {
 		t.Fatalf("failed to created zone: %s", err)

test/etcd_test.go

@@ -31,7 +31,7 @@ func etcdMiddleware() *etcd.Etcd {
 
 // This test starts two coredns servers (and needs etcd). Configure a stubzones in both (that will loop) and
 // will then test if we detect this loop.
-func TestEtcdStubForwarding(t *testing.T) {
+func TestEtcdStubLoop(t *testing.T) {
 	// TODO(miek)
 }
 

test/file_reload_test.go

@@ -13,6 +13,7 @@ import (
 )
 
 func TestZoneReload(t *testing.T) {
+	t.Parallel()
 	log.SetOutput(ioutil.Discard)
 
 	name, rm, err := TempFile(".", exampleOrg)

test/file_test.go

@@ -3,6 +3,7 @@ package test
 import "testing"
 
 func TestTempFile(t *testing.T) {
+	t.Parallel()
 	_, f, e := TempFile(".", "test")
 	if e != nil {
 		t.Fatalf("failed to create temp file: %s", e)

test/kubernetes_test.go

@@ -242,6 +242,7 @@ func createTestServer(t *testing.T, corefile string) (*caddy.Instance, string) {
 }
 
 func TestKubernetesIntegration(t *testing.T) {
+	t.Parallel()
 	corefile :=
 		`.:0 {
     kubernetes cluster.local 0.0.10.in-addr.arpa {

test/metrics_test.go

@@ -16,6 +16,8 @@ import (
 	"github.com/miekg/dns"
 )
 
+// fail when done in parallel
+
 // Start test server that has metrics enabled. Then tear it down again.
 func TestMetricsServer(t *testing.T) {
 	corefile := `example.org:0 {

test/middleware_dnssec_test.go

@@ -12,6 +12,7 @@ import (
 )
 
 func TestLookupBalanceRewriteCacheDnssec(t *testing.T) {
+	t.Parallel()
 	name, rm, err := test.TempFile(".", exampleOrg)
 	if err != nil {
 		t.Fatalf("failed to created zone: %s", err)

test/proxy_test.go

@@ -13,6 +13,7 @@ import (
 )
 
 func TestLookupProxy(t *testing.T) {
+	t.Parallel()
 	name, rm, err := test.TempFile(".", exampleOrg)
 	if err != nil {
 		t.Fatalf("failed to created zone: %s", err)

test/server.go

@@ -3,6 +3,7 @@ package test
 import (
 	"io/ioutil"
 	"log"
+	"sync"
 
 	"github.com/miekg/coredns/core/dnsserver"
 
@@ -12,8 +13,12 @@ import (
 	"github.com/mholt/caddy"
 )
 
+var mu sync.Mutex
+
 // CoreDNSServer returns a CoreDNS test server. It just takes a normal Corefile as input.
 func CoreDNSServer(corefile string) (*caddy.Instance, error) {
+	mu.Lock()
+	defer mu.Unlock()
 	caddy.Quiet = true
 	dnsserver.Quiet = true
 	log.SetOutput(ioutil.Discard)

test/server_test.go

@@ -8,6 +8,7 @@ import (
 
 // Start 2 tests server, server A will proxy to B, server B is an CH server.
 func TestProxyToChaosServer(t *testing.T) {
+	t.Parallel()
 	corefile := `.:0 {
 	chaos CoreDNS-001 miek@miek.nl
 }

test/wildcard_test.go

@@ -13,6 +13,7 @@ import (
 )
 
 func TestLookupWildcard(t *testing.T) {
+	t.Parallel()
 	name, rm, err := test.TempFile(".", exampleOrg)
 	if err != nil {
 		t.Fatalf("failed to created zone: %s", err)