diff --git a/.drone.yml b/.drone.yml
index 8fa4d94..1c6ddef 100644
--- a/.drone.yml
+++ b/.drone.yml
@@ -10,7 +10,8 @@ steps:
 - name: test 
   image: golang
   commands:
-  - go test -parallel 10 -race ./... 
+  # - go test -parallel 10 -race ./... 
+  - go test -race ./... 
 
 - name: golangci-lint
   image: golangci/golangci-lint:v1.53
diff --git a/.golangci.yml b/.golangci.yml
index 29a6459..6c7c222 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -43,6 +43,8 @@ linters:
       - ifshort
       - nosnakecase
 
+      - ireturn # implement provider interface
+
 issues:
   # Excluding configuration per-path, per-linter, per-text and per-source
   exclude-rules:
diff --git a/client.go b/client.go
index 15739e0..d5928f7 100644
--- a/client.go
+++ b/client.go
@@ -124,7 +124,6 @@ func (c *Client) Value(ctx context.Context, path ...string) (Value, error) {
 }
 
 func (c *Client) Watch(ctx context.Context, callback WatchCallback, path ...string) error {
-
 	for idx, prov := range c.providers {
 		provider, ok := prov.(WatchProvider)
 		if !ok {
diff --git a/provider/arg/provider.go b/provider/arg/provider.go
index e9b2228..6104f19 100644
--- a/provider/arg/provider.go
+++ b/provider/arg/provider.go
@@ -106,7 +106,7 @@ func (p *Provider) Name() string {
 	return p.name
 }
 
-func (p *Provider) Value(ctx context.Context, path ...string) (config.Value, error) {
+func (p *Provider) Value(_ context.Context, path ...string) (config.Value, error) {
 	if err := p.parse(); err != nil {
 		return nil, err
 	}
@@ -123,7 +123,11 @@ func (p *Provider) Value(ctx context.Context, path ...string) (config.Value, err
 			}
 
 			return value.Decode(func(v interface{}) error {
-				return json.Unmarshal(data, v)
+				if err := json.Unmarshal(data, v); err != nil {
+					return fmt.Errorf("unmarshal:%w", err)
+				}
+
+				return nil
 			}), nil
 		}
 	}
diff --git a/provider/arg/provider_test.go b/provider/arg/provider_test.go
index 2e759ea..b029e62 100644
--- a/provider/arg/provider_test.go
+++ b/provider/arg/provider_test.go
@@ -58,6 +58,7 @@ func (d *Duration) UnmarshalJSON(in []byte) error {
 	if err != nil {
 		return fmt.Errorf("parse:%w", err)
 	}
+
 	d.Duration = o
 
 	return nil
diff --git a/provider/env/provider.go b/provider/env/provider.go
index b287b34..161583d 100644
--- a/provider/env/provider.go
+++ b/provider/env/provider.go
@@ -45,7 +45,7 @@ func (p *Provider) Name() string {
 	return p.name
 }
 
-func (p *Provider) Value(ctx context.Context, path ...string) (config.Value, error) {
+func (p *Provider) Value(_ context.Context, path ...string) (config.Value, error) {
 	name := p.prefix + p.key(path...)
 	if val, ok := os.LookupEnv(name); ok {
 		return value.JString(val), nil
diff --git a/provider/watcher/provider.go b/provider/watcher/provider.go
index 4ab7561..dc286e0 100644
--- a/provider/watcher/provider.go
+++ b/provider/watcher/provider.go
@@ -67,7 +67,6 @@ func (p *Provider) Watch(ctx context.Context, callback config.WatchCallback, key
 							return
 						}
 						p.logger(ctx, "callback %v:%v", key, err)
-
 					}
 					oldVar = newVar
 				}
diff --git a/provider/watcher/provider_test.go b/provider/watcher/provider_test.go
index ba5d8ba..68725b3 100644
--- a/provider/watcher/provider_test.go
+++ b/provider/watcher/provider_test.go
@@ -2,7 +2,7 @@ package watcher_test
 
 import (
 	"context"
-	"fmt"
+	"strconv"
 	"sync"
 	"sync/atomic"
 	"testing"
@@ -14,6 +14,8 @@ import (
 	"gitoa.ru/go-4devs/config/value"
 )
 
+var _ config.Provider = (*provider)(nil)
+
 type provider struct {
 	cnt int32
 }
@@ -25,7 +27,7 @@ func (p *provider) Name() string {
 func (p *provider) Value(context.Context, ...string) (config.Value, error) {
 	p.cnt++
 
-	return value.JString(fmt.Sprint(p.cnt)), nil
+	return value.JString(strconv.Itoa(int(p.cnt))), nil
 }
 
 func TestWatcher(t *testing.T) {
@@ -57,6 +59,7 @@ func TestWatcher(t *testing.T) {
 		},
 		"tmpname",
 	)
+
 	wg.Wait()
 
 	require.NoError(t, err)
diff --git a/test/provider_suite.go b/test/provider_suite.go
index ea57537..cbb594d 100644
--- a/test/provider_suite.go
+++ b/test/provider_suite.go
@@ -26,10 +26,8 @@ func Run(t *testing.T, provider config.Provider, read []Read) {
 			val, err := provider.Value(ctx, read.Key...)
 			require.NoError(t, err, read.Key)
 			read.Assert(t, val)
-
 		})
 	}
-
 }
 
 type Read struct {
diff --git a/value.go b/value.go
index 26cd231..1095b9a 100644
--- a/value.go
+++ b/value.go
@@ -8,7 +8,7 @@ type Value interface {
 	ReadValue
 	ParseValue
 	UnmarshalValue
-	IsEquals(Value) bool
+	IsEquals(in Value) bool
 }
 
 type UnmarshalValue interface {