Adaptive random data generation for computer solfware testing

Abstract

Although proof of correctness techniques are intellectually acceptable for validation of computer software, they are often not practical. Therefore, program testing techniques are important methods for gaining confidence in the design of a program. Program testing has limitations also, especially since only a very few of the possible combinations of input data values can be used for testing. However, judicious choice of the test data can significantly increase the impact of the testing process. Computer assisted choice of test data using test data generators may become a practical technique, especially once the importance of "unbiased" test data is recognized. Here, a complete software testing system that was used to evaluate various random test data generators is described. An important goal of each of the data generators is to choose data values that are unbiased by any possible program errors or by the programmer. The data values chosen by the generators are based on knowledge of the specifications, not on "inspection" of the program being tested. Control flow and range of variable monitors are automatically inserted in the program to be tested and are used to evaluate the effectiveness of the test procedures. The information gathered from the monitors is used by three of the four test data generators to attempt to reduce the typical inefficiency of random data generators..