On factors that impact the relationship between code coverage and test suite effectiveness: a survey

Software testing is a critical part of software development. As new test cases are generated over time due to software modifications, test suite sizes may grow significantly. Because of time and resource constraints for testing, test suite minimization techniques are needed to remove those test cases from a suite that, due to code modifications over time, have become redundant with respect to the coverage of testing requirements for which they were generated. Prior work has shown that test suite minimization with respect to a given testing criterion can significantly diminish the fault detection effectiveness (FDE) of suites. We present a new approach for test suite reduction that attempts to use additional coverage information of test cases to selectively keep some additional test cases in the reduced suites that are redundant with respect to the testing criteria used for suite minimization, with the goal of improving the FDE retention of the reduced suites. We implemented our approach by modifying an existing heuristic for test suite minimization. Our experiments show that our approach can significantly improve the FDE of reduced test suites without severely affecting the extent of suite size reduction

This study examines the implementation of Test Case Prioritization (TCP) using the Greedy Algorithm (GA) to enhance regression testing efficiency within a financial technology company's software development cycle. With testing durations increasing significantly, this study aims to address inefficiencies by applying the Greedy Algorithm to optimize test suite size and fault detection. The research methodology involves applying the Greedy Algorithm during the Regression Testing phase, comparing the prioritized suite with the original suite using metrics such as Average Percentage Fault Detection (APFD) and Test Suite Size Reduction (TSSR). Results show that the Greedy Algorithm achieved substantial improvements in both test suite size and fault detection effectiveness across different projects. For Project A, the test suite was reduced from 51-22 test cases, achieving a TSSR of 56.8%, with an APFD increase of 206.21%, rising from 0.0853-0.2613. Project B demonstrated even greater optimization, reducing the test suite from 36-8 test cases, resulting in a TSSR of 77.8% and an APFD improvement of 83.92%, rising from 0.3194-0.5875. These outcomes underscore the algorithm’s effectiveness in eliminating redundant test cases, accelerating testing, and enhancing fault detection thereby supporting the company's goal of faster release cycles without compromising quality.

Test case prioritization is used in regression testing to schedule the execution order of test cases so as to expose faults earlier in testing. Over the past few years, many test case prioritization techniques have been proposed in the literature. Most of these techniques require data on dynamic execution in the form of code coverage information for test cases. However, the collection of dynamic code coverage information on test cases has several associated drawbacks including cost increases and reduction in prioritization precision. In this paper, we propose an approach to prioritizing test cases in the absence of coverage information that operates on Java programs tested under the JUnit framework-an increasingly popular class of systems. Our approach, JUnit test case Prioritization Techniques operating in the Absence of coverage information (JUPTA), analyzes the static call graphs of JUnit test cases and the program under test to estimate the ability of each test case to achieve code coverage, and then schedules the order of these test cases based on those estimates. To evaluate the effectiveness of JUPTA, we conducted an empirical study on 19 versions of four Java programs ranging from 2K-80K lines of code, and compared several variants of JUPTA with three control techniques, and several other existing dynamic coverage-based test case prioritization techniques, assessing the abilities of the techniques to increase the rate of fault detection of test suites. Our results show that the test suites constructed by JUPTA are more effective than those in random and untreated test orders in terms of fault-detection effectiveness. Although the test suites constructed by dynamic coverage-based techniques retain fault-detection effectiveness advantages, the fault-detection effectiveness of the test suites constructed by JUPTA is close to that of the test suites constructed by those techniques, and the fault-detection effectiveness of the test suites constructed by some of JUPTA's variants is better than that of the test suites constructed by several of those techniques.

Software testing and retesting occurs continuously during the software development lifecycle to detect errors as early as possible. As the software evolves the size of test suites also grows. When the no of test cases generated are more, obviously size of the test suite will also be more. So the testing time is to be minimized by reducing the execution time of the algorithm used for test data generation and also by introducing minimization procedure for test suite reduction. Due to limited resources and timing constraints for testing, test suite minimization techniques are needed to eliminate redundant test cases as possible. By considering multiple objectives rather than the coverage alone, the test cases are being generated which satisfies the testing requirements. Most of the existing techniques are code-based. In this article we present an approach by modifying an existing heuristic for test suite minimization. Genetic algorithm has been used for random test data generation and the output of GA is given to the minimization procedure for reducing the total no of generated test cases, collectively named as Hybrid Algorithm (HA). The results are satisfactory and show significant improvements in reducing test suite size with minimum execution time. Experiments have been done for simple to medium complexity java programs taken from SIR and execution time is reduced to 5,685ms for a test set. The results are compared with existing method Mutant Gene Algorithm and size of test suite is minimized upto 13.6% using Hybrid Algorithm.

Software testing is a fundamental step in the software development lifecycle. Its purpose is to evaluate the quality of software applications. Regression testing is an important testing methodology in software testing. The purpose of regression testing is to validate the software after each change of its code. This involves adding new test cases to the test suite and running the test suite as the software changes, making the test suite larger. The cost and time of the project are affected by the test suite size. The challenge is to run regression testing with a smaller number of test cases and larger amount of software coverage. Minimization of the test suite with maximization of the software coverage is an NP-complete problem. Search-based software engineering is an important topic in software engineering, which addresses software engineering optimization problems to find the optimal/approximate solution of the given problem. This study investigated an approach to reducing the regression testing effort and saving time. It also solved the regression testing optimization problem by achieving the maximum test suite coverage with the minimum test suite size. Several experiments were conducted to obtain the optimal solutions for the regression testing problem. We propose an optimization methodology that combines a genetic algorithm and a greedy algorithm to optimize regression testing by respectively maximizing the software test coverage and minimizing the test suite size. The proposed methodology can conveniently deliver fault-free, fully covered, and powerful programs for mission-critical functions. It can be applied to test a real-time system that has high requirements for reliability, security, and safety.

The availability of effective test suites is critical for the development and maintenance of reliable software systems. To increase test effectiveness, software developers tend to employ larger and larger test suites. The recent availability of software tools for automatic test generation makes building large test suites affordable, therefore contributing to accelerating this trend. However, large test suites, though more effective, are resources and time consuming and therefore cannot be executed frequently. Reducing them without decreasing code coverage is a needed compromise between efficiency and effectiveness of the test, hence enabling a more regular check of the software under development. We propose a novel approach, namely REDUNET, to reduce a test suite while keeping the same code coverage. We integrate this approach in a complete framework for the automatic generation of efficient and effective test suites, which includes test suite generation, code coverage analysis, and test suite reduction. Our approach formulates the test suite reduction as a set cover problem and applies integer linear programming and a network-based optimisation, which takes advantage of the properties of the control flow graph. We find the optimal set of test cases that keeps the same code coverage in fractions of seconds on real software projects and test suites generated automatically by Randoop. The results on ten real software systems show that the proposed approach finds the optimal minimisation and achieves up to 90% reduction and more than 50% reduction on all systems under analysis. On the largest project our reduction algorithm performs more than three times faster than both integer linear programming alone and the state-of-the-art heuristic Harrold Gupta Soffa.

Testers often represent systems under test in input parameter models. These contain parameters with associated values. Combinations of parameter values, with one value for each parameter, are potential test cases. In most models, some values of two or more parameters cannot be combined. Testers must then detect and avoid or remove these conflicts. This paper proposes two new methods for automatically handling such conflicts and compares these with two existing methods, based on the sizes of the final conflict-free test suites. A test suite reduction method, usable with three of the four investigated methods is also included in the study, resulting in seven studied conflict handling methods. In the experiment, the number and types of conflicts, as well as the size of the input parameter model and the coverage criterion used, are varied. All in all, 3854 test suites with a total of 929,158 test cases were generated. Two methods stand out as tractable and complementary. The best method (called the avoid methods) with respect to test suite size is to avoid selection of test cases with conflicts. However, this method cannot always be used. The second best method (called the replace method), removing conflicts from the final test suite, is completely general.

Regression testing is the process of testing a modified system using the old test suite. As the test suite size is large, system retesting consumes large amount of time and computing resources. This issue of retesting of software systems can be handled using a good test case prioritization technique. A prioritization technique schedules the test cases for execution so that the test cases with higher priority executed before lower priority. The objective of test case prioritization is to detect fault as early as possible so that the debuggers can begin their work earlier. In this paper we propose a new prioritization technique to prioritize the test cases to perform regression testing for Component Based Software System (CBSS). The components and the state changes for a component based software systems are being represented by UML state chart diagrams which are then converted into Component Interaction Graph (CIG) to describe the interrelation among components. Our prioritization algorithm takes this CIG as input along with the old test cases and generates a prioritized test suit taking into account total number of state changes and total number of database access, both direct and indirect, encountered due to each test case. Our algorithm is found to be very effective in maximizing the objective function and minimizing the cost of system retesting when applied to few JAVA projects.

The feedback provided by current testing education tools about the\ndeficiencies in a student's test suite either mimics industry code coverage\ntools or lists specific instructor test cases that are missing from the\nstudent's test suite. While useful in some sense, these types of feedback are\nakin to revealing the solution to the problem, which can inadvertently\nencourage students to pursue a trial-and-error approach to testing, rather than\nusing a more systematic approach that encourages learning. In addition to not\nteaching students why their test suite is inadequate, this type of feedback may\nmotivate students to become dependent on the feedback rather than thinking for\nthemselves. To address this deficiency, there is an opportunity to investigate\nalternative feedback mechanisms that include a positive reinforcement of\ntesting concepts. We argue that using an inquiry-based learning approach is\nbetter than simply providing the answers. To facilitate this type of learning,\nwe present Testing Tutor, a web-based assignment submission platform that\nsupports different levels of testing pedagogy via a customizable feedback\nengine. We evaluated the impact of the different types of feedback through an\nempirical study in two sophomore-level courses. We use Testing Tutor to provide\nstudents with different types of feedback, either traditional detailed code\ncoverage feedback or inquiry-based learning conceptual feedback, and compare\nthe effects. The results show that students that receive conceptual feedback\nhad higher code coverage (by different measures), fewer redundant test cases,\nand higher programming grades than the students who receive traditional code\ncoverage feedback.\n

Software Testing is an important aspect of the real time software development process. Software testing always assures the quality of software product. As associated with software testing, there are few very important issues where there is a need to pay attention on it in the process of software development test. These issues are generation of effective test case and test suite as well as optimization of test case and suite while doing testing of software product. The important issue is that testing time of the test case and test suite. It is very much important that after development of software product effective testing should be performed. So to overcome these issues of optimization, we have proposed new approach for test suite optimization using genetic algorithm (GA). Genetic algorithm is evolutionary in nature so it is often used for optimization of problem by researcher. In this paper, our aim is to study various selections methods like tournament selection, rank selection and roulette wheel selection and then we apply this genetic algorithm (GA) on various programs which will generate optimized test suite with parameters like fitness value of test case, test suite and take minimum amount of time for execution after certain preset generation. In this paper our main objectives as per the experimental investigation, we show that tournament selection works very fine as compared to other methods with respect fitness selection of test case and test suites, testing time of test case and test suites as well as number of requirements.

Code coverage is successfully used to guide white box test design and evaluate the respective test completeness. However, simple overall coverage ratios are often not precise enough to effectively help when a (regression) test suite needs to be reassessed and evolved after software change. We present an approach for test suite assessment and improvement that utilizes code coverage information, but on a more detailed level and adds further evaluation aspects derived from the coverage. The main use of the method is to aid various test suite evolution situations such as removal, refactoring and extension of test cases as a result of code change or test suite efficiency enhancement. We define various metrics to express different properties of test suites beyond simple code coverage ratios, and present the assessment and improvement process as an iterative application of different improvement goals and more specific sub-activities. The method is demonstrated by applying it to improve the tests of one of our experimental systems.

Software testing is one of the important stages of software development. In software development, developers always depend on testing to reveal bugs. In the maintenance stage test suite size grow because of integration of new technique. Addition of new technique force to create new test case which increase the size of test suite. In regression testing new test case may be added to the test suite during the whole testing process. These additions of test cases create possibility of presence of redundant test cases. Due to limitation of time and resource, reduction techniques should be used to identify and remove them. Research shows that a subset of the test case in a suit may still satisfy all the test objectives which is called as representative set. Redundant test case increase the execution cost of the test suite, in spite of NP-completeness of the problem there are few good reduction techniques have been available. In this paper a new approach for test case reduction is proposed. This algorithm use genetic algorithm technique iteratively with varying chromosome length to reduce test case in a test suit by finding representative set of test cases that are fulfill the testing criteria.

Testing is the fundamental technique to assess the correctness of software systems, but it is cost-labored to generate test cases. One solution to change the situation is to automatize some parts of the testing process, especially the generation of test cases using formal theory and technology. The research work in the direction shows the good perspective. This paper targets on the automatic generation of test cases based on IOSTS, which is widely used to model reactive systems with data. When selecting test cases based on a set of test purposes specified by IOSTS or temporal logic, in general, the redundancy phenomena are unavoidable in the derived test suite. Hence, some strategies are presented for eliminating the redundancies in order to reduce the cost of implementing testing. More importantly, the strategies are directly applied to test cases in form of IOSTS, such that it can reduce not only the size of test suite, but also the cost of deriving test cases.

Model-Based Testing (MBT) is a well-known technique that employs formal models to represent reactive systems’ behavior and generates test cases. Such systems have been specified and verified using mostly Finite State Machines (FSMs). There is a plethora of test generation algorithms in the literature; most of them are based on graphs once an FSM can be formally defined as a graph. Nevertheless, there is a lack of studies on analyzing cost and efficiency of FSM-based test generation algorithms. This study compares graph-based algorithms adopted to generate test cases from FSM models. In particular, we compare the Chinese Postman Problem (CPP) and H-Switch Cover (HSC) algorithms with the well-known Depth-First Search (DFS) and Breadth-First Search (BFS) algorithms in the context of covering all-transitions and all-transition-pairs criteria in an FSM. First, a systematic literature mapping was conducted to summarize the methods that have been adopted in MBT, considering FSMs. Second, the main methods found were implemented and analyzed on randomly-generated FSMs, as well as real-world models that represent embedded systems of space applications. To make comparisons, we considered analyses in terms of cost (time), efficiency (mutant analysis) and characteristics of the generated test suites (number of test cases, average length of test cases, largest and smallest test cases, standard deviation and distribution of test cases). In general, CPP presented the best results in terms of number of test cases and test suite size. In addition, CPP also presented low distribution of average length compared to other algorithms.

Database Management System (DBMS) developers have implemented extensive test suites to test their DBMSs. For example, the SQLite test suites contain over 92 million lines of code. Despite these extensive efforts, test suites are not systematically reused across DBMSs, leading to wasted effort. Integration is challenging, as test suites use various test case formats and rely on unstandardized test runner features. We present a unified test suite, SQuaLity, in which we integrated test cases from three widely-used DBMSs, SQLite, PostgreSQL, and DuckDB. In addition, we present an empirical study to determine the potential of reusing these systems' test suites. Our results indicate that reusing test suites is challenging: First, test formats and test runner commands vary widely; for example, SQLite has 4 test runner commands, while MySQL has 112 commands with additional features, to, for example, execute file operations or interact with a shell. Second, while some test suites contain mostly standard-compliant statements (e.g., 99% in SQLite), other test suites mostly test non-standardized functionality (e.g., 31% of statements in the PostgreSQL test suite are nonstandardized). Third, test reuse is complicated by various explicit and implicit dependencies, such as the need to set variables and configurations, certain test cases requiring extensions not present by default, and query results depending on specific clients. Despite the above findings, we have identified 3 crashes, 3 hangs, and multiple compatibility issues across four different DBMSs by executing test suites across DBMSs, indicating the benefits of reuse. Overall, this work represents the first step towards test-case reuse in the context of DBMSs, and we hope that it will inspire follow-up work on this important topic.