diff --git a/manifest_test.go b/manifest_test.go
index 0d7fdbc5..a77eeb6b 100644
--- a/manifest_test.go
+++ b/manifest_test.go
@@ -251,7 +251,7 @@ func generateTestFiles(t *testing.T, root string, resources []dresource) {
 			resources[i].size = size
 
 			// this relies on the proper directory parent being defined.
-			if err := ioutil.WriteFile(p, d, resource.mode); err != nil {
+			if err := os.WriteFile(p, d, resource.mode); err != nil {
 				t.Fatalf("error writing %q: %v", p, err)
 			}
 		case rdirectory: