how to detect if overfitting xgboost print test set AUC

Question

I would like to check if we overfit, i used function like this

model <- xgboost(data = x1, label = data$early,
                     max.depth = 2000, eta = 0.5, nthread = 2, nrounds = 15, eval_metric = "auc",
                     objective = "binary:logistic")

print

[1] train-auc:0.851959 
[2] train-auc:0.907667 
[3] train-auc:0.941878 
[4] train-auc:0.964039 
[5] train-auc:0.973722 
[6] train-auc:0.981834 
[7] train-auc:0.987278 
[8] train-auc:0.990866 
[9] train-auc:0.994628 
[10]    train-auc:0.996348 
[11]    train-auc:0.997236 
[12]    train-auc:0.997954 
[13]    train-auc:0.998647 
[14]    train-auc:0.999019 
[15]    train-auc:0.999104 

but it only print train-auc, how should i print test AUC?