Testing: A Roadmap

Mary Jean HarroldCollege Of Computing

Georgia Institute Of Technology

Presented ByPrashanth LAnmol N M

Introduction

•Definition

•Purposes for which testing is performed

•Key Concepts

•Advantages

•Disadvantages

Introduction

•Definition

–Software testing is any activity aimed at evaluating an attribute or capability of a program or system and determining that it meets its required results.

–Constitutes more than 50% of cost of software development

Introduction

Purposes

•To improve quality •For Verification & Validation (V&V)

–Functionality (Exterior Quality)-Correctness ,Reliability Usability Integrity

–Engineering (interior quality)-Efficiency ,Testability Documentation Structure

– Adaptability (future quality )-Flexibility Reusability Maintainability

•For reliability estimation

Introduction

Key Concepts

•Taxonomy–correctness testing–performance testing–reliability testing–security testing

•Testing Automation

•When to Stop Testing?

Introduction

•Correctness Testing- –Minimum Requirements of Software.–can be either black box or white box

Black Box - treats s/w as blackbox.only the inputs/outputs visible basic functionality testing. White Box-structure & flow of software under test visible.

•Performance Testing-Design problems in software that cause the system performance to degrade

•Reliability Testing-robustness of a software component is the degree to which it can function correctly in the presence of exceptional inputs or stressful environmental conditions

Security Testing-include identifying and removing software flaws that may potentially lead to security violations, and validating the effectiveness of security measures. Simulated security attacks can be performed to find vulnerabilities

Introduction

•Testing Automation– Automation is a good way to cut down time and cost. – Software testing tools and techniques usually suffer from a lack of generic applicability and scalability.

•When to Stop Testing?–Testing is a trade-off between budget, time and quality. –It is driven by profit models.–pessimistic time, budget, or test cases -- are exhausted.–optimistic reliability meets the requirement, or the benefit from

continuing testing cannot justify the testing cost.

•Advantages–Easy generation of test cases & Instrumentation of software.–Process automation & execution in expected environment.

Roadmap

Fundamental Research

– Testing Component Based Systems – Testing Based on Precode Artifacts– Testing Evolving Software– Demonstrating Effectiveness of Testing Techniques– Using Testing Artifacts– Other Testing Techniques– Methods & Tools– Empirical Studies– Testing Resources

Testing Component Based Systems

•Issues – Component Provider (Developer of the Components)

Views Components independently of the context.

– Component User (Application Developer) Views Components relevant to the application.•Limiting Factor

–Availability of Source Code

•Roadmap Suggested–Types of Testing Information needed.–Techniques for representing & computing the types of testing info the user needs.–Techniques to use the information provided with the component for testing the application.

Testing Based On Precode Artifacts

•Issues – Design– Requirements– Architectural Specifications

•Issue Under Spotlight– Architecture

•Roadmap Suggested– Use of formal notations used for s/w architecture – Develop techniques to be used with architectural specification for test-case development.– Develop techniques to evaluate s/w architectures for testability.

Testing Evolving Software• Regression testing:

Validate modified software to ensure no new errors introduced. ONE OF THE MOST EXPENSIVE PART !!!

• Some useful techniques* select subset of test suite of previous from previous testing. * techniques to help manage growth in size of test suite.* assess regression testability.

• Testing techniques needed ….* not only for software but also for architecture and requirements.* manage test suites themselves.* identify parts of modified software for which new test cases are required.* identify test cases no longer needed.* prioritize test cases.* asses the test suite themselves.

Demonstrating effectiveness of Testing Techniques

• How ????

* Increase developers confidence.* software behavior* identify classes of faults for a given test criteria.* provide visual interface.* determine interaction among test selection criteria and ways to combine.

• Research been done In ….

* evaluation criteria to determine adequacy of test suites and test cases that inspire confidence.* test cases based on either software’s intended behavior or purely on code.* test cases based on data-flow in a program.* use existing testing techniques to test visual programming languages.* test complex Boolean expressions.* mutation analysis and approximation ( ex: can avoid testing pointer variable in data flow analysis.

Establishing Effective Process for Testing

• Need to develop process for planning and implementation of Testing.

• Some of the currently used or proposed techniques ….* Develop a test plan during requirements gathering phase and implementation of the test plan after s/w implementation phase. Useful ?

* what does Microsoft do ?- frequently synchronize what people are doing.- periodically stabilize the product in increments as project proceeds.- build and test a version every night !!! ( only Microsoft can do…!)

* perpetual testing - Build foundation for treating analysis and test ongoing activities for improved quality.

* selective regression testing where we test one version and gather testing artifacts such as I/o pairs and coverage information.

* explicit progress of regression testing that integrates many key testing techniques into development and maintenance of evolving software.

Establishing Effective Process for Testing. Cont’d

• Some Open questions …

– Does Microsoft nightly rebuild, minimize testing later ?

– Does testing show all the software qualities ?

– Can results obtained from testing be generalized ?

• Some useful suggestions …

– Integrate various quality techniques and tools

– Combine static analysis with testing

Using Testing Artifacts

• Artifacts include :– Execution traces of software’s execution with test cases.– Results of execution like pass/fail of software for given test cases.

• Useful : Store results and use for retesting modified software.

• A whole bunch of research is done on this, some of the proposed ….* use dynamic program slices derived from execution traces along with pass/fail results for execution traces to identify potential faulty code.

apply heuristics to find out subset of test suite that passed and failed.

* identify program invariants and develop test cases generation.

* use coverage information to predict the magnitude of regression testing.

* use coverage information also to select test cases from test suite for use in regression testing.

Using Testing Artifacts. Cont’d…

• Proposed research cont’d….

* Use artifacts to for test suite reduction and prioritization.

* Perform concept analysis on coverage info and compute relationships among executed entities. Helps in uncovering properties of test suites.

* Path spectra identifies paths where control diverges in program execution which is helpful in debugging, testing and maintenance. Expensive !

* Use branch spectra which is less expensive profiling.

* Using visual tools to analyze test info.

• Additional research Needed ….* use of testing artifacts for software engineering tasks.* identify types of info software engineers and managers need (data mining)

Other Testing Techniques

• Some other techniques helpful in reaching end goal (quality software)

* Need for a scalable automatic test data generation

* Static analysis required but expensive. Need for a scalable analysis technique that can be used to compute required information.

* data-flow analysis expensive and hence need for efficient instrumentation and recording techniques.

Method and Tools

• Goal– Develop efficient methods and tools that can be used by practitioners to test their software.

• Complaint– Software Engineering technology requires on average 18 years to be transferred in to

practice !!!!!!! We need to reduce this time for technology transfer. • Reasons

– techniques developed demonstrated on contrived or toy system. Not Scalable !

• What we need

– Development of tools and methods for industrial setting to demonstrate the usefulness of techniques proposed

– Techniques proposed should be scalable.

– Develop robust prototypes and identify the context in which they can function and use them to perform the experiments to demonstrate the techniques.

Method and Tools. Cont’d ….

• What we need. Cont’d …

– Tools to consider computation trade offs like Precision Vs Efficiency.

– Automatic development of method and tools on the lines of compilers.

– Develop tools that are attractive to practitioners.

– Finally the developed tools require minimal involvement of Software Engineers.

Empirical Studies

• What does it mean ?– Studies which will help demonstrate the scalability and usefulness of the

techniques in practice in other words feedback for future research.

• Difficulties in doing Empirical Studies

– Difficulty in acquiring sufficient robust implementation of these techniques

– Difficulty in obtaining sufficient experimental subjects (software and test suites)

• Solutions

– Collect sets of experimental subjects and make them available for researchers.

– Create sanitized information that would reveal no proprietary information and still useful for experimentation.

Testing Resources

• Workshops, Conferences, Journals and Useful Links

– Workshop on Strategic Directions in Software Quality 1996 . (ACM)

– National Science Foundation & Computational Research Association

– Workshop on Role of Software Architectures in Testing and Analysis. (INRC)

– International Conference on Software Engineering Workshop on Testing Distributed Component-based Systems.

– Middle Tennessee State’s STORM Software Testinghttp://www.mtsu.edu/~storm/

– Reliable Software Technology’s Software Assurance Hotlisthttp://www.rstcorp.com/hotlist

– Research Institute’s Software Quality Hotlisthttp://www.soft.com/Institute/HotList/index.html

– Newsgroup: comp.software.testing

Conclusions

• Relevance To Embedded Systems

Emphasizes the basic stages-Sets up the next paper.

Talks about evolving systems-ES evolve by the second.

Talks about component based testing-COTS.

Emphasizes the need for Testing based on Precode Artifacts- Software Architecture.

Examining Current Techniques to demonstrate scalability & usefulness of techniques in practice-Empirical.

• Weakness – Nil