Tomohiko Takagi

Mutation Testing of "Go-Back" Functions Based on Pushdown Automata

A go-back (GB) function for canceling recent user or system operations and going back to and resuming of previous state(s) is very often used regardless of the application domain. Therefore, faulty handling of them can cause severe damages in those applications. This paper proposes a mutation-based approach to testing GB functions modeled by pushdown automata. Novel mutation operators, recent coverage criteria, and a new algorithm for test case generation are introduced. A case study validates the approach and discusses its characteristics.

Concurrent N-Switch Coverage Criterion for Generating Test Cases from Place/Transition Nets

A PN (place/transition net) is known as an algebraic model that is useful for describing concurrent, distributed and asynchronous properties of software, and it is also recognized as a model of MBT (model-based testing) that is an important technique for developing high quality software. We propose a concurrent N-switch coverage criterion to generate test cases of high coverage levels from a PN representing test specifications of software. All sequences of successive fireable transitions of length N+1 on the PN can be covered by executing test cases that satisfy the concurrent N-switch coverage criterion. This paper shows its processes, work products, algorithms, and examples.

Constructing a usage model for statistical testing with source code generation methods

In statistical testing, testcases are generated using a usage model which defines usage of software as probability distribution on a state machine diagram. The aim of this study is to automatically construct a usage distribution from operational data, which assists construction of a reasonable usage model at low cost. This paper shows that applying source code generation methods based on a state machine diagram makes it possible. The prototype system has been developed to support the presented method.

Construction Method of a High-Order Markov Chain Usage Model

Statistical testing is a method for evaluating software reliability. Test cases are generated according to a usage model that represents the behavior of users. Accuracy of a usage model is an important factor since effectiveness of statistical testing (i.e., accuracy of software reliability) depends on it. This paper shows the usage model construction method using high-order Markov chains in order to construct accurate usage models. It is illustrated that the usage models constructed by this method are more accurate than traditional ones based on a simple or time-homogeneous Markov chain and can be constructed automatically. Some problems for more effective statistical testing are then found.

Test case selection technique for regression testing using differential control flow graphs

This paper shows a new technique to select effective test cases for regression testing of software. In the technique, an UCN (update complexity number) of each module of software under test is calculated based on a differential control flow graph, and then test cases that execute modules with larger UCNs are selected automatically.

Test Strategies Using Operational Profiles Based on Decision Tables

In this paper, we propose a DTOP (Decision Table-based Operational Profile) that is a novel operational profile constructed by giving probability distributions to a decision table, and then discuss test strategies using the DTOP in order to effectively apply OPBT (Operational Profile-Based Testing) to software that includes complex logical relationship among inputs and outputs.

Overview of a place/transition net-based mutation testing framework to obtain test cases effective for concurrent software

This paper shows a framework for a PNBMT (place/transition net-based mutation testing technique) that consists of three tools, that is, a mutant PN generator, a negative test case generator, and a mutation analyzer.

The Pushdown Automaton and Its Coverage Criterion for Testing Undo/Redo Functions of Software

UR (undo/redo) functions of software play a great role as the achievement of usability, and they are widely used. However, there are no systematic methods of testing the UR functions that are essentially complex. This paper shows systematic method of modeling the behavior of software using a PDA (pushdown automaton) and generating testcases for the UR functions. The testcase generation is based on the coverage criterion designed for the PDA. We applied this method to an example of software and evaluated its effectiveness.

Usage Distribution Coverage: What Percentage of Expected Use Has Been Executed in Software Testing?

This paper shows that a UD (Usage Distribution) coverage criterion based on an operational profile measures the progress of software testing from users’ viewpoint effectively. The UD coverage criterion focuses on not only the structure of software but the usage characteristics of users. Its measuring object is the software usage weighted with the probability of the operational profile, and intuitively it shows what percentage of expected use in operational environments has been tested. It solves the problem that usual coverage criteria focussing only on the structure of software are not substantiated by software reliability and do not identify the degree of an importance of each measuring object. This paper describes the definitions and examples of UD coverage.

GB Coverage Criteria: The Measurement for Testing a "Go Back" Function Based on a Pushdown Automaton

A GB (go back) function of software for canceling recent user operations and going back to previous states is indispensable to realize usability, and is implemented in much software regardless of its application domain. This paper shows GB coverage criteria that measure the progress of GB function testing based on a PDA (pushdown automaton). They are the extensions of existing coverage criteria based on a state machine, such as a state and N-switch.