def test_dt_increase_acc(dummy_titanic):
    X_train, y_train, X_test, y_test = dummy_titanic

    acc_list = []
    auc_list = []
    for num_trees in [1, 3, 7, 15]:
        rf = RandomForest(num_trees=num_trees, depth_limit=7, col_subsampling=0.7, row_subsampling=0.7)
        rf.fit(X_train, y_train)
        pred = rf.predict(X_test)
        pred_binary = np.round(pred)
        acc_list.append(accuracy_score(y_test, pred_binary))
        auc_list.append(roc_auc_score(y_test, pred))

    assert sorted(acc_list) == acc_list, 'Accuracy should increase as number of trees increases.'
    assert sorted(auc_list) == auc_list, 'AUC ROC should increase as number of trees increases.'