diff --git a/remotes/docker/fetcher_fuzz.go b/remotes/docker/fetcher_fuzz.go
index b98886c59..849670a18 100644
--- a/remotes/docker/fetcher_fuzz.go
+++ b/remotes/docker/fetcher_fuzz.go
@@ -25,6 +25,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"net/url"
+	"strconv"
 
 	refDocker "github.com/containerd/containerd/reference/docker"
 )
@@ -37,7 +38,7 @@ func FuzzFetcher(data []byte) int {
 
 	s := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
 		rw.Header().Set("content-range", fmt.Sprintf("bytes %d-%d/%d", 0, dataLen-1, dataLen))
-		rw.Header().Set("content-length", fmt.Sprintf("%d", dataLen))
+		rw.Header().Set("content-length", strconv.Itoa(dataLen))
 		rw.Write(data)
 	}))
 	defer s.Close()
diff --git a/remotes/docker/fetcher_test.go b/remotes/docker/fetcher_test.go
index 07cc90a24..695d6045f 100644
--- a/remotes/docker/fetcher_test.go
+++ b/remotes/docker/fetcher_test.go
@@ -25,6 +25,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"net/url"
+	"strconv"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -39,8 +40,8 @@ func TestFetcherOpen(t *testing.T) {
 		if start > 0 {
 			rw.Header().Set("content-range", fmt.Sprintf("bytes %d-127/128", start))
 		}
-		rw.Header().Set("content-length", fmt.Sprintf("%d", len(content[start:])))
-		rw.Write(content[start:])
+		rw.Header().Set("content-length", strconv.Itoa(len(content[start:])))
+		_, _ = rw.Write(content[start:])
 	}))
 	defer s.Close()