diff --git a/src/net/conf_test.go b/src/net/conf_test.go
index d0d450aa8a..3736709295 100644
--- a/src/net/conf_test.go
+++ b/src/net/conf_test.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || aix
+//go:build unix
 
 package net
 
diff --git a/src/net/dnsclient_unix_test.go b/src/net/dnsclient_unix_test.go
index 81117b8c75..83ce7b28e9 100644
--- a/src/net/dnsclient_unix_test.go
+++ b/src/net/dnsclient_unix_test.go
@@ -10,7 +10,6 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"io/fs"
 	"os"
 	"path"
 	"path/filepath"
@@ -2531,7 +2530,7 @@ func TestLookupOrderFilesNoSuchHost(t *testing.T) {
 	if runtime.GOOS == "openbsd" {
 		// Set error to ErrNotExist, so that the hostLookupOrder
 		// returns hostLookupFiles for openbsd.
-		resolvConf.err = fs.ErrNotExist
+		resolvConf.err = os.ErrNotExist
 	}
 
 	if !conf.forceUpdateConf(&resolvConf, time.Now().Add(time.Hour)) {
@@ -2539,12 +2538,9 @@ func TestLookupOrderFilesNoSuchHost(t *testing.T) {
 	}
 
 	tmpFile := filepath.Join(t.TempDir(), "hosts")
-	f, err := os.OpenFile(tmpFile, os.O_CREATE|os.O_WRONLY, 0660)
-	if err != nil {
+	if err := os.WriteFile(tmpFile, []byte{}, 0660); err != nil {
 		t.Fatal(err)
 	}
-	defer f.Close()
-
 	testHookHostsPath = tmpFile
 
 	const testName = "test.invalid"