diff --git a/internal/home/config.go b/internal/home/config.go
index fedb43ab357..d660ddb834a 100644
--- a/internal/home/config.go
+++ b/internal/home/config.go
@@ -114,8 +114,7 @@ type dnsConfig struct {
 	FiltersUpdateIntervalHours uint32           `yaml:"filters_update_interval"` // time period to update filters (in hours)
 	DnsfilterConf              filtering.Config `yaml:",inline"`
 
-	// UpstreamTimeout is the timeout for querying upstream servers in
-	// seconds.
+	// UpstreamTimeout is the timeout for querying upstream servers.
 	UpstreamTimeout Duration `yaml:"upstream_timeout"`
 
 	// LocalDomainName is the domain name used for known internal hosts.
diff --git a/internal/home/duration.go b/internal/home/duration.go
index 50086f5e7e7..6e6ab79e041 100644
--- a/internal/home/duration.go
+++ b/internal/home/duration.go
@@ -6,7 +6,7 @@ import (
 	"github.com/AdguardTeam/golibs/errors"
 )
 
-// Duration is a wrapper of time.Duration extending it's functionality.
+// Duration is a wrapper for time.Duration providing functionality for encoding.
 type Duration struct {
 	// time.Duration is embedded here to avoid implementing all the methods.
 	time.Duration
diff --git a/internal/home/duration_test.go b/internal/home/duration_test.go
index 4c728aadebe..afbff16d508 100644
--- a/internal/home/duration_test.go
+++ b/internal/home/duration_test.go
@@ -1,6 +1,7 @@
 package home
 
 import (
+	"bytes"
 	"encoding/json"
 	"strings"
 	"testing"
@@ -11,17 +12,17 @@ import (
 	yaml "gopkg.in/yaml.v2"
 )
 
-// durationMarshalTester is a helper struct to simplify testing different
+// durationEncodingTester is a helper struct to simplify testing different
 // Duration marshalling and unmarshalling cases.
-type durationMarshalTester struct {
-	PtrMap   map[string]*Duration `json:"ptr_map"`
-	PtrSlice []*Duration          `json:"ptr_slice"`
-	PtrValue *Duration            `json:"ptr_value"`
-	PtrArray [1]*Duration         `json:"ptr_array"`
-	Map      map[string]Duration  `json:"map"`
-	Slice    []Duration           `json:"slice"`
-	Value    Duration             `json:"value"`
-	Array    [1]Duration          `json:"array"`
+type durationEncodingTester struct {
+	PtrMap   map[string]*Duration `json:"ptr_map"   yaml:"ptr_map"`
+	PtrSlice []*Duration          `json:"ptr_slice" yaml:"ptr_slice"`
+	PtrValue *Duration            `json:"ptr_value" yaml:"ptr_value"`
+	PtrArray [1]*Duration         `json:"ptr_array" yaml:"ptr_array"`
+	Map      map[string]Duration  `json:"map"       yaml:"map"`
+	Slice    []Duration           `json:"slice"     yaml:"slice"`
+	Value    Duration             `json:"value"     yaml:"value"`
+	Array    [1]Duration          `json:"array"     yaml:"array"`
 }
 
 const nl = "\n"
@@ -36,12 +37,12 @@ const (
 		`"value":"1ms",` +
 		`"array":["1ms"]` +
 		`}`
-	yamlStr = `ptrmap:` + nl +
+	yamlStr = `ptr_map:` + nl +
 		`  dur: 1ms` + nl +
-		`ptrslice:` + nl +
+		`ptr_slice:` + nl +
 		`- 1ms` + nl +
-		`ptrvalue: 1ms` + nl +
-		`ptrarray:` + nl +
+		`ptr_value: 1ms` + nl +
+		`ptr_array:` + nl +
 		`- 1ms` + nl +
 		`map:` + nl +
 		`  dur: 1ms` + nl +
@@ -54,28 +55,43 @@ const (
 
 // checkFields verifies m's fields.  It expects the m to be unmarshalled from
 // one of the constant strings above.
-func (m *durationMarshalTester) checkFields(t *testing.T, d Duration) {
+func (m *durationEncodingTester) checkFields(t *testing.T, d Duration) {
+	// PtrMap
+
 	require.NotNil(t, m.PtrMap)
 
 	fromPtrMap, ok := m.PtrMap["dur"]
 	require.True(t, ok)
 	require.NotNil(t, fromPtrMap)
 
+	// PtrSlice
+
 	require.Len(t, m.PtrSlice, 1)
+
 	fromPtrSlice := m.PtrSlice[0]
 	require.NotNil(t, fromPtrSlice)
 
+	// PtrArray
+
 	fromPtrArray := m.PtrArray[0]
 	require.NotNil(t, fromPtrArray)
 
+	// PtrValue
+
 	require.NotNil(t, m.PtrValue)
 
+	// Map
+
 	var fromMap Duration
 	fromMap, ok = m.Map["dur"]
 	require.True(t, ok)
 
+	// Slice
+
 	require.Len(t, m.Slice, 1)
 
+	// Value Check
+
 	assert.Equal(t, d, *fromPtrMap)
 	assert.Equal(t, d, *fromPtrSlice)
 	assert.Equal(t, d, *m.PtrValue)
@@ -86,15 +102,15 @@ func (m *durationMarshalTester) checkFields(t *testing.T, d Duration) {
 	assert.Equal(t, d, m.Array[0])
 }
 
-// val is the default time.Duration value to be used throughout the tests of
+// defaultTestDur is the default time.Duration value to be used throughout the tests of
 // Duration.
-const val = time.Millisecond
+const defaultTestDur = time.Millisecond
 
 func TestDuration_MarshalText(t *testing.T) {
-	d := Duration{val}
+	d := Duration{defaultTestDur}
 	dPtr := &d
 
-	m := durationMarshalTester{
+	m := durationEncodingTester{
 		PtrMap:   map[string]*Duration{"dur": dPtr},
 		PtrSlice: []*Duration{dPtr},
 		PtrValue: dPtr,
@@ -105,7 +121,7 @@ func TestDuration_MarshalText(t *testing.T) {
 		Array:    [1]Duration{d},
 	}
 
-	b := &strings.Builder{}
+	b := &bytes.Buffer{}
 	t.Run("json", func(t *testing.T) {
 		t.Cleanup(b.Reset)
 		err := json.NewEncoder(b).Encode(m)
@@ -126,16 +142,16 @@ func TestDuration_MarshalText(t *testing.T) {
 		data, err := d.MarshalText()
 		require.NoError(t, err)
 
-		assert.EqualValues(t, []byte(val.String()), data)
+		assert.EqualValues(t, []byte(defaultTestDur.String()), data)
 	})
 }
 
 func TestDuration_UnmarshalText(t *testing.T) {
-	d := Duration{val}
-	var m *durationMarshalTester
+	d := Duration{defaultTestDur}
+	var m *durationEncodingTester
 
 	t.Run("json", func(t *testing.T) {
-		m = &durationMarshalTester{}
+		m = &durationEncodingTester{}
 
 		r := strings.NewReader(jsonStr)
 		err := json.NewDecoder(r).Decode(m)
@@ -145,7 +161,7 @@ func TestDuration_UnmarshalText(t *testing.T) {
 	})
 
 	t.Run("yaml", func(t *testing.T) {
-		m = &durationMarshalTester{}
+		m = &durationEncodingTester{}
 
 		r := strings.NewReader(yamlStr)
 		err := yaml.NewDecoder(r).Decode(m)
@@ -164,8 +180,6 @@ func TestDuration_UnmarshalText(t *testing.T) {
 	})
 
 	t.Run("bad_data", func(t *testing.T) {
-		const wrongData = `abc`
-
-		assert.Error(t, (&Duration{}).UnmarshalText([]byte(wrongData)))
+		assert.Error(t, (&Duration{}).UnmarshalText([]byte(`abc`)))
 	})
 }