loadUser() if not able to load() credential return error (#19931)

cmd/signature-v4_test.go

@@ -37,6 +37,12 @@ func niceError(code APIErrorCode) string {
 }
 
 func TestDoesPolicySignatureMatch(t *testing.T) {
+	_, fsDir, err := prepareFS(context.Background())
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer removeRoots([]string{fsDir})
+
 	credentialTemplate := "%s/%s/%s/s3/aws4_request"
 	now := UTCNow()
 	accessKey := globalActiveCred.AccessKey