In Defense of Simple Techniques for Neural Network Test Case Selection

Although deep learning (DL) software has been pervasive in various applications, the brittleness of deep neural networks (DNN) hinders their deployment in many tasks especially high-stake ones. To mitigate the risk accompanied with DL software fault, a variety of DNN testing techniques have been proposed such as test case selection. Among those test case selection or prioritization methods, the uncertainty-based ones such as DeepGini have demonstrated their effectiveness in finding DNN's faults. Recently, TestRank, a learning based test ranking method has shown their out-performance over simple uncertainty-based test selection methods. However, this is achieved with a more complicated design which needs to train a graph convolutional network and a multi-layer Perceptron. In this paper, we propose a novel and lightweight DNN test selection method to enhance the effectiveness of existing simple ones. Besides the DNN model's uncertainty on test case itself, we take into account model's uncertainty on its neighbors. This could diversify the selected test cases and improve the effectiveness of existing uncertainty-based test selection methods. Extensive experiments on 5 datasets demonstrate the effectiveness of our approach.