Pull request: 2273 clean tests output

Merge in DNS/adguard-home from 2273-clean-tests-output to master

Closes #2273.

Squashed commit of the following:

commit 7571a33
Merge: f17df0f a19523b
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Mon Nov 16 15:45:30 2020 +0300

    Merge branch 'master' into 2273-clean-tests-output

commit f17df0f
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Mon Nov 16 15:35:42 2020 +0300

    home: move build constraint on top line

commit 3717c8e
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Mon Nov 16 15:24:50 2020 +0300

    all: add improvements to changelog

commit de6d5af
Merge: 43d4f7a 394fc5a
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Mon Nov 16 15:04:38 2020 +0300

    Merge branch 'master' into 2273-clean-tests-output

commit 43d4f7a
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Mon Nov 16 13:38:13 2020 +0300

    dnsfilter: remove redundant test logging

commit 7194c14
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Mon Nov 16 12:19:14 2020 +0300

    testutil: improve comments

commit 9f17ab0
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Sat Nov 14 01:22:08 2020 +0300

    nclient4: fix wrong function name

commit f355749
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Sat Nov 14 01:07:22 2020 +0300

    testutil: fix comments and naming

commit f8c50a2
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Fri Nov 13 14:09:50 2020 +0300

    testutil: create a package and include it

commit f169cdc
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Thu Nov 12 20:15:58 2020 +0300

    agherr: discard loggers output

commit 360e736
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Thu Nov 12 20:09:55 2020 +0300

    all: replace default log writer with ioutil.Discard

    Closes #2273.

CHANGELOG.md

@@ -14,6 +14,10 @@ and this project adheres to
 - This changelog :-) (#2294).
 - `HACKING.md`, a guide for developers.
 
+### Changed
+
+- Improved tests output (#2273).
+
 ### Fixed
 
-- Infinite loop in `/dhcp/find_active_dhcp` (#2301).
+- Infinite loop in `/dhcp/find_active_dhcp` (#2301).

internal/agherr/agherr_test.go

@@ -5,9 +5,14 @@ import (
 	"fmt"
 	"testing"
 
+	"github.com/AdguardTeam/AdGuardHome/internal/testutil"
 	"github.com/stretchr/testify/assert"
 )
 
+func TestMain(m *testing.M) {
+	testutil.DiscardLogOutput(m)
+}
+
 func TestError_Error(t *testing.T) {
 	testCases := []struct {
 		name string

internal/dhcpd/dhcpd_test.go

@@ -9,9 +9,14 @@ import (
 	"testing"
 	"time"
 
+	"github.com/AdguardTeam/AdGuardHome/internal/testutil"
 	"github.com/stretchr/testify/assert"
 )
 
+func TestMain(m *testing.M) {
+	testutil.DiscardLogOutput(m)
+}
+
 func testNotify(flags uint32) {
 }
 

internal/dhcpd/nclient4/client_test.go

@@ -17,11 +17,16 @@ import (
 	"testing"
 	"time"
 
+	"github.com/AdguardTeam/AdGuardHome/internal/testutil"
 	"github.com/hugelgupf/socketpair"
 	"github.com/insomniacslk/dhcp/dhcpv4"
 	"github.com/insomniacslk/dhcp/dhcpv4/server4"
 )
 
+func TestMain(m *testing.M) {
+	testutil.DiscardLogOutput(m)
+}
+
 type handler struct {
 	mu       sync.Mutex
 	received []*dhcpv4.DHCPv4

internal/dnsfilter/dnsfilter_test.go

@@ -5,11 +5,16 @@ import (
 	"net"
 	"testing"
 
+	"github.com/AdguardTeam/AdGuardHome/internal/testutil"
 	"github.com/AdguardTeam/urlfilter/rules"
 	"github.com/miekg/dns"
 	"github.com/stretchr/testify/assert"
 )
 
+func TestMain(m *testing.M) {
+	testutil.DiscardLogOutput(m)
+}
+
 var setts RequestFilteringSettings
 
 // HELPERS
@@ -290,7 +295,6 @@ func TestSafeSearchCacheGoogle(t *testing.T) {
 		t.Fatalf("Failed to lookup for %s", safeDomain)
 	}
 
-	t.Logf("IP addresses: %v", ips)
 	ip := ips[0]
 	for _, i := range ips {
 		if i.To4() != nil {

internal/dnsforward/dnsforward_test.go

@@ -18,6 +18,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/AdguardTeam/AdGuardHome/internal/testutil"
 	"github.com/AdguardTeam/AdGuardHome/internal/util"
 
 	"github.com/AdguardTeam/AdGuardHome/internal/dhcpd"
@@ -28,6 +29,10 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+func TestMain(m *testing.M) {
+	testutil.DiscardLogOutput(m)
+}
+
 const (
 	tlsServerName     = "testdns.adguard.com"
 	testMessagesCount = 10

internal/home/auth_test.go

@@ -9,9 +9,14 @@ import (
 	"testing"
 	"time"
 
+	"github.com/AdguardTeam/AdGuardHome/internal/testutil"
 	"github.com/stretchr/testify/assert"
 )
 
+func TestMain(m *testing.M) {
+	testutil.DiscardLogOutput(m)
+}
+
 func prepareTestDir() string {
 	const dir = "./agh-test"
 	_ = os.RemoveAll(dir)
@@ -85,9 +90,11 @@ type testResponseWriter struct {
 func (w *testResponseWriter) Header() http.Header {
 	return w.hdr
 }
+
 func (w *testResponseWriter) Write([]byte) (int, error) {
 	return 0, nil
 }
+
 func (w *testResponseWriter) WriteHeader(statusCode int) {
 	w.statusCode = statusCode
 }

internal/home/home_test.go

@@ -1,5 +1,7 @@
 // +build !race
 
+// TODO(e.burkov): remove this weird buildtag.
+
 package home
 
 import (

internal/querylog/qlog_test.go

@@ -8,10 +8,15 @@ import (
 	"github.com/AdguardTeam/dnsproxy/proxyutil"
 
 	"github.com/AdguardTeam/AdGuardHome/internal/dnsfilter"
+	"github.com/AdguardTeam/AdGuardHome/internal/testutil"
 	"github.com/miekg/dns"
 	"github.com/stretchr/testify/assert"
 )
 
+func TestMain(m *testing.M) {
+	testutil.DiscardLogOutput(m)
+}
+
 func prepareTestDir() string {
 	const dir = "./agh-test"
 	_ = os.RemoveAll(dir)

internal/stats/stats_test.go

@@ -7,9 +7,14 @@ import (
 	"sync/atomic"
 	"testing"
 
+	"github.com/AdguardTeam/AdGuardHome/internal/testutil"
 	"github.com/stretchr/testify/assert"
 )
 
+func TestMain(m *testing.M) {
+	testutil.DiscardLogOutput(m)
+}
+
 func UIntArrayEquals(a, b []uint64) bool {
 	if len(a) != len(b) {
 		return false

internal/testutil/testutil.go

@@ -0,0 +1,19 @@
+// Package testutil contains utilities for testing.
+package testutil
+
+import (
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"github.com/AdguardTeam/golibs/log"
+)
+
+// DiscardLogOutput runs tests with discarded logger output.
+func DiscardLogOutput(m *testing.M) {
+	// TODO(e.burkov): Refactor code and tests to not use the global mutable
+	// logger.
+	log.SetOutput(ioutil.Discard)
+
+	os.Exit(m.Run())
+}

internal/update/update_test.go

@@ -8,9 +8,14 @@ import (
 	"os"
 	"testing"
 
+	"github.com/AdguardTeam/AdGuardHome/internal/testutil"
 	"github.com/stretchr/testify/assert"
 )
 
+func TestMain(m *testing.M) {
+	testutil.DiscardLogOutput(m)
+}
+
 func startHTTPServer(data string) (net.Listener, uint16) {
 	mux := http.NewServeMux()
 	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {

internal/util/auto_hosts_test.go

@@ -8,10 +8,15 @@ import (
 	"testing"
 	"time"
 
+	"github.com/AdguardTeam/AdGuardHome/internal/testutil"
 	"github.com/miekg/dns"
 	"github.com/stretchr/testify/assert"
 )
 
+func TestMain(m *testing.M) {
+	testutil.DiscardLogOutput(m)
+}
+
 func prepareTestDir() string {
 	const dir = "./agh-test"
 	_ = os.RemoveAll(dir)