diff --git a/interop/client/client.go b/interop/client/client.go
index cc599cf4..4f952076 100644
--- a/interop/client/client.go
+++ b/interop/client/client.go
@@ -304,8 +304,8 @@ func doServiceAccountCreds(tc testpb.TestServiceClient) {
 
 var (
 	testMetadata = metadata.MD{
-		"key1": "value1",
-		"key2": "value2",
+		"key1": []string{"value1"},
+		"key2": []string{"value2"},
 	}
 )
 
@@ -381,6 +381,12 @@ func main() {
 				grpclog.Fatalf("Failed to create JWT credentials: %v", err)
 			}
 			opts = append(opts, grpc.WithPerRPCCredentials(jwtCreds))
+		} else if *testCase == "jwt_token_creds" {
+			jwtCreds, err := oauth.NewServiceAccountFromFile(*serviceAccountKeyFile, *oauthScope)
+			if err != nil {
+				grpclog.Fatalf("Failed to create JWT credentials: %v", err)
+			}
+			opts = append(opts, grpc.WithPerRPCCredentials(jwtCreds))
 		}
 	}
 	conn, err := grpc.Dial(serverAddr, opts...)
diff --git a/test/end2end_test.go b/test/end2end_test.go
index c23d8262..d436d03e 100644
--- a/test/end2end_test.go
+++ b/test/end2end_test.go
@@ -75,12 +75,7 @@ func (s *testServer) EmptyCall(ctx context.Context, in *testpb.Empty) (*testpb.E
 		if _, ok := md["user-agent"]; !ok {
 			return nil, grpc.Errorf(codes.DataLoss, "got extra metadata")
 		}
-	//	kv := []string{"ua"}
-	//	for _, entry := range md["user-agent"]{
-	//		kv = append(kv,entry)
-	//	}
-	//	grpc.SendHeader(ctx, metadata.Pairs(kv))
-	grpc.SendHeader(ctx, metadata.Pairs("ua", md["user-agent"][0]))
+		grpc.SendHeader(ctx, metadata.Pairs("ua", md["user-agent"][0]))
 	}
 	return new(testpb.Empty), nil
 }