Programu testavimo metodai

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Programu testavimo metodai

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IVADAS

• Modulio paskirtis

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Tikslai

• Apibudinti SWEBOK projekta
• Apibrežti modulio vieta mokymo plane
• Aprašyti modulio žiniu struktura
• Apibudinti praktines užduotis

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SWEBOK

• Software Configuration Management
• Software Construction (Version 0.5)
• Software Design
• Software Engineering Infrastructure
• Software Engineering Management
• Software Engineering Process
• Software Evolution and Maintenance
• Software Quality Analysis
• Software Requirements Analysis
• Software Testing

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Mokymo programa (Curricula ) Programu sistemu
inžinerijos magistras (Master in Software
Engineering)    
  2000 09 12  
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Bendros knygos

• Pressmann Software Engineering Theory and
  Practice, 6 laida
• J. Sommerville, I. Software Engineering 8 laida
• http//www.elen.ktu.lt/rsei/PT/index.htm

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Testavimo knygos

• http//www.softwareqatest.com/

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Programavimo krize

• Programines irangos klaidos yra geriau žinomos
  negu sekmes atvejai
• Programavimo krize prognozuota prieš 30 metu taip
  niekada ir neivyko ir programuotojams pavyko
  sumažinti nesekmiu kieki bei darbuotoju poreiki
• Problemos, kurios kamuoja programuotojus
  pagrindinai susietos su tinkamu programines
  irangos kurimu ir jos palaikymu negu kad su
  gavimu programines irangos, kuri funkcionuoja
  korektiškai

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Teisybe

• Matematikui, fizikui ir inžinieriui buvo pasakyta
  Visi nelyginiai skaiciai yra pirminiai
• Matematikas pasakys nesamone, 9 yra nelyginis
  skaicius bet ne pirminis
• Fizikas pasakys pažiurekim, trys yra pirminis,
  penki yra pirminis, septyni yra pirminis, atrodo,
  kad teisybe
• Inžinierius pasakys pažiurekim, trys yra
  pirminis, penki yra pirminis, septyni yra
  pirminis, devyni yra pirminis, vienuolika yra
  pirminis, atrodo, kad teisybe

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Programu testavimas

• Istoriškai nepopuliarus tarp
• vadybininku
• programuotoju
• studentu
• Testavimas ir daugelis programavimo inovaciju
  išaugo iš programavimo krizes

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Testavimas Musu patyrimas
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Kada sustoti?
Test Case Generation
Verification
Test Coverage
Yes
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Testavimo pavyzdys
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Automatinis testavimas
Test Case Generation
Verification
Test Coverage
Yes
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Automatinis testavimas
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Kas tai yra programu testavimas?

• The process of executing computer software in
  order to determine whether the results it
  produces are correct, Glass 79
• The process of executing a program with the
  intent of finding errors, Myers 79
• Program testing can be used to show the presence
  of bugs, but never their absence, Dijkstra 72

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Kas tai yra programu testavimas?

• The aim is not to discover errors but to provide
  convincing evidence that there are none, or to
  show that particular classes of faults are not
  present, Hennell 84
• Testing is the measure of software quality,
  Hetzel 85

Kas vadinama programu testavimu?
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Kas tai yra programu testavimas?

• The process of operating a system or component
  under specified conditions, observing or
  recording the results, and making an evaluation
  of some aspect of the system or component.
• IEEE/ANSI, 1990

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Testavimas priklauso nuo požiurio

• If our goal is to show the absence of errors, we
  will find very few of them
• If our goal is to show the presence of errors,
  we will discover a large number of them

Myers, 1979
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Testavimo laikas

• 50 Brooks/Myers, 1970s
• 80 Arthur Andersons Director of testing in
  North America, 1990s

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Testuotoju ir programuotoju santykis

• 15-10 Mainframes
• i.e.,1 tester for every 5 to 10 developers
• 23 Microsoft, 1992
• 21 Lotus (for 1-2-3 Windows)
• 12 Average of 4 major companies,1992 Microsoft,
  Borland, WordPerfect, Novell

Koks testuotoju ir programuotoju santykis?
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Programu testavimo problemos

• poorly expressed requirements
• informal design techniques
• nothing executable until coding stage
• Huge input set consider testing software that
  categorises an exam grade 101 inputs
• consider testing software that categorises two
  exam grades 101101 inputs!

Kokios programu testavimo problemos?
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Kas tai yra programu testavimas?

• Exhaustive software testing is intractable
  (sunkiai suvaldomas)
• Even if all possible inputs could be identified,
  the problem of identifying expected results is
  undecidable (neišsprendžiama)
• Weyuker (1979) has shown that there is no
  algorithm that can determine if a given
  statement, branch or path will be exercised!

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Programu testavimo apibrežimas

• Software testing consists of the dynamic
  verification of the behavior of a program on a
  finite set of test cases, suitably selected from
  the usually infinite executions domain, against
  the specified expected behavior.

Kaip apibrežiamas programu testavimas?
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Dinaminis

• This term means testing always implies executing
  the program on valued inputs. Static analysis
  techniques, such as peer review and inspection
  (that sometimes are improperly referred to as
  "static testing"), are not considered as part of
  this KA nor is program execution on symbolic
  inputs, or symbolic evaluation

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Baigtinis

• Clearly the tests are not selected literally from
  an infinite set of possible tests, but a very
  large finite one (the set of all bit strings
  shorter than some length). Nonetheless, for even
  simple programs, so many test cases are
  theoretically possible that exhaustive testing
  could require even years to execute. This is why
  in practice the number of tests can generally be
  considered infinite. However, the number of
  executions which can realistically be observed in
  testing must obviously be finite, and -more than
  this- it must be manageable. Indeed, testing
  always implies a trade-off between limited
  resources and schedules, and inherently unlimited
  test requirements this conflict points to well
  known problems of testing, both technical in
  nature (criteria for deciding test adequacy) and
  managerial in nature (estimating the effort to
  put in testing)

Kokia itaka turi testo ilgis?
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Išrinktu

• The many proposed test techniques essentially
  differ in how they select the (finite) test set,
  and testers must be aware that different
  selection criteria may yield largely different
  effectiveness. The problem of identifying the
  most suitable selection criterion under given
  conditions is still under research.

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Laukiami rezultatai

• It must be possible to decide whether the
  observed outcomes of program execution are
  acceptable or not, otherwise the testing effort
  would be useless. The observed behavior may be
  checked against user's expectations (commonly
  referred to as testing for validation) or against
  a functional specification (testing for
  verification). The test pass/fail decision is
  referred to as the oracle problem, which can be
  addressed with different approaches.

Kas tai yra orakulo problema?
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Statiniai metodai

• Software testing is a means for quality
  evaluation. In the SQA chapter of the SWEBOK,
  activities and techniques for quality analysis
  are categorized into static techniques (no code
  execution), and dynamic techniques (code
  execution). Both categories are useful. Although
  this chapter focuses on testing, that is dynamic,
  we would like to emphasize that static techniques
  are equally important for the purpose of building
  quality in a software product. Static techniques
  are covered into the SQA KA description

Kas tai yra statiniai testavimo metodai?
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Testavimo veikla

• In the years, the view of software testing has
  evolved towards a more constructive attitude.
  Testing is no longer seen as an activity that
  starts only after the coding phase is complete,
  with the limited purpose of finding mistakes.
  Software testing is nowadays seen as an activity
  that encompasses the whole development process,
  and is an important part itself of the actual
  construction. Indeed, planning for testing starts
  since the early stages of requirement analysis,
  and test plans and procedures are systematically
  and continuously refined as the development
  proceeds. These activities of planning and
  designing tests constitute themselves a useful
  input to designers for highlighting potential
  weaknesses.

Ka apima testavimo veikla?
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Klaidu vengimas

• As more extensively discussed in the SQA chapter,
  the right attitude towards quality is one of
  prevention it is better to avoid problems,
  rather than repairing them. Testing must be seen
  as a means primarily for demonstrating that the
  prevention has been effective, but also for
  identifying anomalies in those cases in which,
  for some reason, it has been not. Finally, it is
  worth recognizing that even after a good testing,
  the system could still contain mistakes. The
  remedy to system failures after delivery is
  provided by (corrective) maintenance actions. The
  maintenance issues of software engineering are
  covered into the Software Evolution and
  Maintenance chapter of the SWEBOK

Kuo remiasi klaidu vengimo strategija?
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Temos

• A.Testing Basic Concepts and Definitions
• B.Test Levels
• C.Test Techniques
• D.Test-related Measures
• E.Managing the Test Process
• F.Test Tools.

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A.Bazines testavimo koncepcijos ir apibrežimai

• When the outcome of a test execution diverges
  from the expected, a failure is observed, whose
  cause is a fault. These and other basic
  definitions within software testing area, as well
  as an introduction to the terminology, will be
  provided in Part A Testing Basic Concepts and
  Definitions. In the same section, the scope of
  the KA will be laid down, also in relation with
  other activities.

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B.Testavimo lygiai

• Software testing is usually performed at
  different levels along the development process.
  That is to say, the object of the test can vary
  a whole program, part of it (functionally or
  structurally related), a single module. The
  latter subject is expanded in Part B Test Levels.
  This consists of two (orthogonal) subsections
  B.1 lists the phases in which the testing of
  large software systems is traditionally
  subdivided. In B.2 testing for specific
  conditions or properties is instead considered,
  and is referred to as "Objectives of testing".
  Clearly not all listed types of testing apply to
  every system, nor has every possible type been
  listed, but those most generally applied.

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Testavimo paskirtis

• Testing is conducted in view of a specific
  purpose (test objective), which is stated more or
  less explicitly, and with varying degrees of
  precision. Stating the objective in precise,
  quantitative terms allows for establishing
  control over the test process.

Kokia testavimo paskirtis?
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Testavimo tikslas

• One of testing aims is to expose failures (as
  many as possible), and many popular test
  techniques have been developed for this
  objective. These techniques variously attempt to
  "break" the program, by running identified
  classes of (deemed equivalent) executions the
  leading principle underlying such techniques is
  being as much systematic as possible in
  identifying a representative set of program
  behaviors (generally in the form of subclasses of
  the input domain). However, a comprehensive view
  of the KA of testing as a means for quality must
  include other as important objectives for
  testing, e.g., reliability measurement, usability
  evaluation, contractors acceptance, for which
  different approaches would be taken. Note that
  the test objective varies with the test object,
  i.e., in general different purposes are addressed
  at the different levels of testing.

Koks testavimo tikslas?
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Testavimo kriterijai

• The test objective determines how the test set is
  identified, both with regard to its consistency
  -how much testing is enough for achieving the
  stated objective?- and its composition -which
  test cases should be selected for achieving the
  stated objective?-, although usually the "for
  achieving the stated objective" part is left
  implicit and only the first part of the two
  italicized questions above is posed. Criteria for
  addressing the first question are referred to as
  test adequacy criteria, while for the second as
  test selection criteria

Kas tai yra testavimo kriterijai?
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C.Testavimo metodai

• As already said, several Test Techniques have
  been developed in the last two decades according
  to various criteria, and new ones are still
  proposed. "Generally accepted" techniques will be
  described in Part C.

Kas tai yra testavimo metodai?
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D.Testavimo matavimai

• Sometimes, it can happen that confusion is made
  between test objectives and techniques. For
  instance, branch coverage is a popular test
  technique. Achieving a specified branch coverage
  measure should not be considered per se as the
  objective of testing it is a means to improve
  the chances of finding failures (by
  systematically exercising every program branch
  out of a decision point). To avoid such
  misunderstandings, a clear distinction should be
  made between test measures which evaluate the
  test set, like measures of coverage, and those
  which instead provide an evaluation of the
  program under test, based on the observed test
  outputs, like reliability

Kam reiklaingi testavimo matavimai?
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E. Testavimo proceso valdymas

• Testing concepts, strategies, techniques and
  metrics need to be integrated into a defined and
  controlled process, which is run by people. The
  test process should support testing activities
  and testing teams, from test planning to test
  outputs evaluation, in such a way as to provide
  justified assurance that the test objectives are
  met cost-effectively. Issues relative to Managing
  the Test Process are expanded in Part E.

Kokia testavimo proceso paskirtis?
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F. Testavimo priemones

• Software testing is a very expensive and
  labor-intensive part of development. For this
  reason, tools are instrumental to support test
  activities. Moreover, in order to enhance
  cost-effectiveness ratio, a key issue has always
  been pushing test automation as much as possible.
  Existing tools and concepts related to automating
  the constituent parts of test process are
  addressed in Part F Test Tools

Kam skirtos testavimo priemones?
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Bendra Užduotis

• 1.     Suformuoti darbo grupe iš 4 asmenu
• 2.     Parinkti darbo grupes pavadinima
• 3 Nusiusti laiška destytojui adresu
  vak_at_soften.ktu.lt
• Susirašineti su destytoju tik šiuo adresu. Laiške
  kaip subject nurodyti darbo grupes varda ir per
  brukšneli laiško numeri. Grupei, kurios vardas
  Namas pirmam laiške nurodyti subject Namas-1.
  Pirmam laiške nurodyti grupes varda, grupes
  studentu varda, pavarde, grupe ir paprašyti
  atsiusti projekto užduoti. Atsakymas bus
  siunciamas su Reply.

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Bendra Užduotis

• 4. Duotam algoritmui sudaryti programa
  nurodytomis priemonemis. Detaliai aprašyti
  užduoti ir algoritma, pateikti strukturograma.
  Programa turi tureti ne mažiau kaip penkis
  atskirai testuojamus vienetus. Sudaryti programos
  testavimo plana. Bent vienas vienetas turi buti
  automatiškai ištestuotas ivairiais kriterijais.
  Parengti testavimo dokumentacija. Programa
  pateikiama kompaktiniam diske ir pristatymo metu
  suinstaliuojama i nurodyta kompiuteri, o po
  pristatymo išinstaliuojama arba pateikiama
  serveryje. Pristatymo metu pateikti viena lapa,
  kuriame nurodoma grupes vardas, sudetis,
  pagrindiniai atliktos užduoties privalumai

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Programavimo budas

• 5. Gali buti trys programavimo budai
• A Programuojama Java kalba, programa
  paleidžiama su naršykle ir ja vykdo vartotojo
  kompiuteris
• B - Programuojama C arba C ir php, programa
  paleidžiama su naršykle ir vykdoma serveryje
• C- Programuojama C arba C, instaliacine
  programa nuskaitoma iš serverio i vartotojo
  kompiuteri, programa suinstaliuojama ir vykdoma
  vartotojo kompiuteryje

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Funkciju sasaja

• 1.   Funkcijos sasaja ( char iejimo-vektorius,
  char išejimo-vektorius, int iejimu-skaicius,
  int išejimu-skaicius, int sekmes-požymis)
• Sekmes-požymis 1 sekmingai paskaiciuota, 0 -
  nepaskaiciuota
•  

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Vertinimo Taisykles

• Galutinis pažymys G skaiciuojamas pagal formule
• G ((A E)/2)0,5 S0,2 P 0,3
• A Apklausa iš pakartojimo
• E- Egzaminas
• S- pasisakymas paskirta tema
• P- projektine užduotis
• ir apvalinamas pagal matematines taisykles iki
  sveikaskaitinio skaiciaus.