Black box & white-box testing technique
- 1. Testing CompetencyTesting Competency 11 White Box & Black BoxWhite Box & Black Box Testing TechniquesTesting Techniques ManishManish Roopa SRoopa S
- 2. Testing Competency 2 What does Test meanWhat does Test mean The word “TEST” is derived from the LatinThe word “TEST” is derived from the Latin word “Testum” meaning a pottery vesselword “Testum” meaning a pottery vessel used to measure or assessused to measure or assess
- 3. Testing Competency 3 Software TestingSoftware Testing Testing of software means assessing orTesting of software means assessing or Measuring the software to determineMeasuring the software to determine its QUALITYits QUALITY Area of testing is one of the key processArea of testing is one of the key process areas of project life cycle in ensuringareas of project life cycle in ensuring the QUALITY of the softwarethe QUALITY of the software
- 4. Testing Competency 4 QUALITYQUALITY What is Quality product ?What is Quality product ? A quality product is one which is fit for use.A quality product is one which is fit for use. A quality product is one which is producedA quality product is one which is produced as per pre-defined specifications.as per pre-defined specifications.
- 5. Testing Competency 5 Various TestingVarious Testing TechniquesTechniques Structural & FunctionalStructural & Functional Verification & Validation (V&V)Verification & Validation (V&V) Static & DynamicStatic & Dynamic White-Box & Black-BoxWhite-Box & Black-Box
- 6. Testing Competency 6 Levels of TestingLevels of Testing Levels of TestingLevels of Testing Testing TechniquesTesting Techniques Unit TestingUnit Testing Structural Testing IntegrationIntegration Structural & Functional SystemSystem Functional, Risk based AcceptanceAcceptance Functional, Risk based
- 7. Testing Competency 7 Test Design MethodsTest Design Methods Black-Box and White-Box are Test DesignBlack-Box and White-Box are Test Design MethodsMethods
- 8. Testing Competency 8 Black-Box TestingBlack-Box Testing Black Box Testing is testing technique havingBlack Box Testing is testing technique having no knowledge of the internalno knowledge of the internal functionality/structure of the systemfunctionality/structure of the system Synonyms for Black-Box are Behavioral,Synonyms for Black-Box are Behavioral, Functional, Opaque-Box, Closed-Box etc.Functional, Opaque-Box, Closed-Box etc.
- 9. Testing Competency 9 contd…contd… Black-box Testing focuses on testing theBlack-box Testing focuses on testing the function of the program or application against itsfunction of the program or application against its specificationspecification Determines whether combinations of inputs andDetermines whether combinations of inputs and operations produce expected resultsoperations produce expected results When black box testing is applied to softwareWhen black box testing is applied to software engineering, the tester would only know theengineering, the tester would only know the "legal" inputs and what the expected outputs"legal" inputs and what the expected outputs should be, but not how the program actuallyshould be, but not how the program actually arrives at those outputsarrives at those outputs
- 10. Testing Competency 10 Focus of Black-Box TestingFocus of Black-Box Testing In this technique, we do not use the codeIn this technique, we do not use the code to determine a test suite; rather, knowingto determine a test suite; rather, knowing the problem that we're trying to solve, wethe problem that we're trying to solve, we come up with four types of test data:come up with four types of test data: Easy-to-compute dataEasy-to-compute data Typical dataTypical data Boundary / extreme dataBoundary / extreme data Bogus dataBogus data
- 11. Testing Competency 11 Black-Box TestingBlack-Box Testing TechniquesTechniques Equivalence PartitioningEquivalence Partitioning Boundary Value AnalysisBoundary Value Analysis Error GuessingError Guessing Cause-Effect GraphingCause-Effect Graphing
- 12. Testing Competency 12 Equivalence PartitioningEquivalence Partitioning An equivalence class is a subset of dataAn equivalence class is a subset of data that is representative of a larger classthat is representative of a larger class Equivalence partitioning is a technique forEquivalence partitioning is a technique for testing equivalence classes rather thantesting equivalence classes rather than undertaking exhaustive testing of eachundertaking exhaustive testing of each value of the larger classvalue of the larger class
- 13. Testing Competency 13 Example - EPExample - EP For example, a program which edits creditFor example, a program which edits credit limits within a given range ($10,000 -limits within a given range ($10,000 - $15,000) would have three equivalence$15,000) would have three equivalence classesclasses < $10,000 (invalid)< $10,000 (invalid) Between $10,000 and $15,000 (valid)Between $10,000 and $15,000 (valid) > $15,000 (invalid)> $15,000 (invalid)
- 14. Testing Competency 14 Boundary AnalysisBoundary Analysis This technique consists of developing testThis technique consists of developing test cases and data that focus on the input andcases and data that focus on the input and output boundaries of a given functionoutput boundaries of a given function
- 15. Testing Competency 15 Example – Boundary AnalysisExample – Boundary Analysis In the same credit limit example, boundaryIn the same credit limit example, boundary analysis would test.analysis would test. Low boundary -/+ one ($9,999 and $10,001)Low boundary -/+ one ($9,999 and $10,001) On the boundary ($10,000 and $15,000)On the boundary ($10,000 and $15,000) Upper boundary -/+ one ($14,999 andUpper boundary -/+ one ($14,999 and $15,001)$15,001)
- 16. Testing Competency 16 Error GuessingError Guessing Test cases can be developed based uponTest cases can be developed based upon the intuition and experience of the testerthe intuition and experience of the tester For example, where one of the inputs isFor example, where one of the inputs is the date, a tester may try February 29,the date, a tester may try February 29, 20012001
- 17. Testing Competency 17 Cause-Effect GraphingCause-Effect Graphing Cause-effect graphing is a technique forCause-effect graphing is a technique for developing test cases for programs fromdeveloping test cases for programs from the high-level specifications (A high-levelthe high-level specifications (A high-level specification states desired characteristicsspecification states desired characteristics of the system)of the system) These characteristics can be used toThese characteristics can be used to derive test dataderive test data
- 18. Testing Competency 18 Example – Cause EffectExample – Cause Effect For example, a program that has specifiedFor example, a program that has specified responses to eight characteristic stimuli (calledresponses to eight characteristic stimuli (called causes) given some input has 256 "types" ofcauses) given some input has 256 "types" of input (i.e., those with characteristics 1 & 3; 5, 7input (i.e., those with characteristics 1 & 3; 5, 7 & 8 etc.)& 8 etc.) A poor approach is to generate 256 test casesA poor approach is to generate 256 test cases A more methodical approach is to use theA more methodical approach is to use the program specifications to analyze the program'sprogram specifications to analyze the program's effect on the various types of inputseffect on the various types of inputs
- 19. Testing Competency 19 contd…contd… The program's output domain can be partitionedThe program's output domain can be partitioned into various classes called effectsinto various classes called effects For example, inputs with characteristic 2 mightFor example, inputs with characteristic 2 might be subsumed by those with characteristics 3 &be subsumed by those with characteristics 3 & 4. Hence, it would not be necessary to test4. Hence, it would not be necessary to test inputs with characteristic 2 and characteristics 3inputs with characteristic 2 and characteristics 3 & 4, for they cause the same effect& 4, for they cause the same effect This analysis results in a partitioning of theThis analysis results in a partitioning of the causes according to their corresponding effectscauses according to their corresponding effects
- 20. Testing Competency 20 contd…contd… A limited entry decision table is then constructedA limited entry decision table is then constructed from the directed graph reflecting thesefrom the directed graph reflecting these dependencies (i.e., causes 2 & 3 result in effectdependencies (i.e., causes 2 & 3 result in effect 4; causes 2, 3 & 5 result in effect 6 etc.)4; causes 2, 3 & 5 result in effect 6 etc.) The decision table is then reduced and testThe decision table is then reduced and test cases chosen to exercise each column of thecases chosen to exercise each column of the tabletable Since many aspects of the cause-effect graphingSince many aspects of the cause-effect graphing can be automated, it is an attractive tool forcan be automated, it is an attractive tool for aiding in the generation of Functional Test casesaiding in the generation of Functional Test cases
- 21. Testing Competency 21 Advantages of Black-BoxAdvantages of Black-Box TestingTesting More effective on larger units of code thanMore effective on larger units of code than glass box testingglass box testing Tester needs no knowledge ofTester needs no knowledge of implementation, including specificimplementation, including specific programming languagesprogramming languages Tester and programmer are independentTester and programmer are independent of each otherof each other
- 22. Testing Competency 22 Advantages of Black-BoxAdvantages of Black-Box Testing Contd…Testing Contd… Tests are done from a user's point of viewTests are done from a user's point of view Will help to expose any ambiguities orWill help to expose any ambiguities or inconsistencies in the specificationsinconsistencies in the specifications Test cases can be designed as soon asTest cases can be designed as soon as the specifications are completethe specifications are complete
- 23. Testing Competency 23 Disadvantages of Black-BoxDisadvantages of Black-Box TestingTesting Only a small number of possible inputs canOnly a small number of possible inputs can actually be tested, to test every possible inputactually be tested, to test every possible input stream would take nearly foreverstream would take nearly forever Without clear and concise specifications, testWithout clear and concise specifications, test cases are hard to designcases are hard to design There may be unnecessary repetition of testThere may be unnecessary repetition of test inputs if the tester is not informed of test casesinputs if the tester is not informed of test cases the programmer has already triedthe programmer has already tried
- 24. Testing Competency 24 Disadvantages of Black-Box TestingDisadvantages of Black-Box Testing Contd…Contd… May leave many program paths untestedMay leave many program paths untested Cannot be directed toward specificCannot be directed toward specific segments of code which may be verysegments of code which may be very complex (and therefore more error prone)complex (and therefore more error prone)
- 25. Testing Competency 25 White-Box TestingWhite-Box Testing White-box test design allows one to peekWhite-box test design allows one to peek inside the "box“inside the "box“ Synonyms for White-box are Structural,Synonyms for White-box are Structural, Glass-box and Clear-boxGlass-box and Clear-box
- 26. Testing Competency 26 cont…cont… White-box Testing assumes that the pathWhite-box Testing assumes that the path of logic in a unit or program is knownof logic in a unit or program is known White-box Testing consists of testingWhite-box Testing consists of testing paths, branch by branch, to producepaths, branch by branch, to produce predictable resultspredictable results Focuses specifically on using internalFocuses specifically on using internal knowledge of the software to guide theknowledge of the software to guide the selection of test dataselection of test data
- 27. Testing Competency 27 White-Box TestingWhite-Box Testing TechniquesTechniques Statement CoverageStatement Coverage execute all statements at least onceexecute all statements at least once Decision CoverageDecision Coverage execute each decision direction at least onceexecute each decision direction at least once Condition CoverageCondition Coverage execute each decision with all possibleexecute each decision with all possible outcomes at least onceoutcomes at least once
- 28. Testing Competency 28 cont…cont… Decision/Condition CoverageDecision/Condition Coverage execute all possible combinations of conditionexecute all possible combinations of condition outcomes in each decisionoutcomes in each decision Multiple Condition CoverageMultiple Condition Coverage invoke each point of entry at least onceinvoke each point of entry at least once Choose the combinations of techniquesChoose the combinations of techniques appropriate for the applicationappropriate for the application
- 29. Testing Competency 29 Statement CoverageStatement Coverage Necessary but not sufficient, doesn’t address allNecessary but not sufficient, doesn’t address all outcomes of decisionsoutcomes of decisions For exampleFor example ………….. Begin()Begin() If (function1())If (function1()) OpenFile1()OpenFile1() ElseElse Shutdown();Shutdown(); ……………… Here if the first IF statement is true thenHere if the first IF statement is true then Shutdown will never occurShutdown will never occur
- 30. Testing Competency 30 Decision CoverageDecision Coverage Validates the Branch Statements in softwareValidates the Branch Statements in software Overcomes the drawbacks of statementOvercomes the drawbacks of statement coveragecoverage Each decision is tested for a TrueEach decision is tested for a True && FalseFalse valuevalue Each branch direction must be traversed atEach branch direction must be traversed at least onceleast once Branches like if…else, while, for do...whileBranches like if…else, while, for do...while are to be evaluated for both true and falseare to be evaluated for both true and false Test cases will be arrived with the help of aTest cases will be arrived with the help of a Decision tableDecision table
- 31. Testing Competency 31 Cont…Cont… Decision TableDecision Table • Table which helps to derive the test casesTable which helps to derive the test cases StepsSteps • Identify the variables which are responsible forIdentify the variables which are responsible for decisiondecision • Identify the total number of decisions (GiveIdentify the total number of decisions (Give numbers to them like IF1, IF2… While1, While2numbers to them like IF1, IF2… While1, While2 etc)etc) • Put thePut the variablesvariables as rows andas rows and decisionsdecisions asas verticalsverticals • Start to map the values for each variablesStart to map the values for each variables corresponding to each decisionscorresponding to each decisions
- 32. Testing Competency 32 An ExampleAn Example Procedure liability (age, sex, married, premium);Procedure liability (age, sex, married, premium); beginbegin premium=500;premium=500; If ((age<25) and (sex=male) and (not married))If ((age<25) and (sex=male) and (not married)) IF-1IF-1 thenthen premium=Premium+1500;premium=Premium+1500; elseelse (if (married or (sex=female))(if (married or (sex=female)) IF-2IF-2 thenthen premium=premium-200;premium=premium-200; If( (age>45) and (age<65))If( (age>45) and (age<65)) IF-3IF-3 thenthen premium= premium-100;premium= premium-100; end;end; Here variables areHere variables are age, sexage, sex andand marriedmarried Decisions are IF1; IF2 ; IF3Decisions are IF1; IF2 ; IF3
- 33. Testing Competency 33 DecisionDecision CoverageCoverage AgeAge SexSex MarriedMarried TestTest casecase IF-1IF-1 <25<25 MaleMale FalseFalse (1) 23 M F(1) 23 M F IF-1IF-1 <25<25 FemaleFemale FalseFalse (2) 23 F F(2) 23 F F IF-2IF-2 ** FemaleFemale ** (2)(2) IF-2IF-2 >=25>=25 MaleMale FalseFalse (3) 50 M F(3) 50 M F IF-3IF-3 <=45<=45 FemaleFemale ** (2)(2) IF-3IF-3 >45>45 <65<65 ** ** (3)(3) Decision TableDecision Table
- 34. Testing Competency 34 Condition CoverageCondition Coverage Validates logical relations and conditionsValidates logical relations and conditions All the conditions should be executed at leastAll the conditions should be executed at least once for the both false and trueonce for the both false and true Conditions using relational and logical operatorsConditions using relational and logical operators should be checked for all possible outcomesshould be checked for all possible outcomes Condition coverage checks for true and falseCondition coverage checks for true and false outcome of each Boolean sub expressionoutcome of each Boolean sub expression Test cases will be arrived from using sameTest cases will be arrived from using same Decision table by putting conditions in place ofDecision table by putting conditions in place of decisionsdecisions
- 35. Testing Competency 35 Test conditionsTest conditions ConditionCondition CoverageCoverage AgeAge SexSex MarriedMarried Test CaseTest Case IF-1IF-1 <25<25 FemaleFemale FalseFalse (1) 23 F F(1) 23 F F IF-1IF-1 >=25>=25 MaleMale TrueTrue (2) 30 M T(2) 30 M T IF-2IF-2 ** MaleMale TrueTrue (2)(2) IF-2IF-2 ** FemaleFemale FalseFalse (1)(1) IF-3IF-3 <=45<=45 ** ** (1)(1) IF-3IF-3 >45>45 ** ** (3) 70 F F(3) 70 F F IF-3IF-3 <65<65 ** ** (2)(2) IF-3IF-3 >=65>=65 ** ** (3)(3)
- 36. Testing Competency 36 Condition/Decision Coverage We may not always get result either in decision coverage or condition coverage. In such cases, go in for decision & condition coverage Test cases will be arrived form both decision as well as condition coverage
- 37. Testing Competency 37 Condition/Decision Test caseCondition/Decision Test case Decision/condition coverageDecision/condition coverage AgeAge SexSex MarriedMarried Test CaseTest Case IF-1(decision)IF-1(decision) <25<25 MaleMale FalseFalse (1) 23 M F(1) 23 M F IF-1(decision)IF-1(decision) <25<25 FemaleFemale FalseFalse (2) 23 F F(2) 23 F F IF-1(condition)IF-1(condition) <25<25 FemaleFemale FalseFalse (2)(2) IF-1(condition)IF-1(condition) >=25>=25 MaleMale TrueTrue (3) 70 M T(3) 70 M T IF-2(decision)IF-2(decision) ** FemaleFemale ** (2)(2) IF-2(decision)IF-2(decision) >=25>=25 MaleMale FalseFalse (4) 50 M F(4) 50 M F IF-2(condition)IF-2(condition) ** MaleMale TrueTrue (3)(3) IF-2(condition)IF-2(condition) ** FemaleFemale FalseFalse (2)(2) IF-3(decision)IF-3(decision) <=45<=45 ** ** (2)(2) IF-3(decision)IF-3(decision) >45, <65>45, <65 ** ** (4)(4) IF-3(condition)IF-3(condition) <=45<=45 ** ** (2)(2) IF-3(condition)IF-3(condition) >45>45 ** ** (4)(4) IF-3(condition)IF-3(condition) <65<65 ** ** (4)(4) IF-3(condition)IF-3(condition) >=65>=65 ** ** (3)(3)
- 38. Testing Competency 38 Multiple ConditionMultiple Condition CoverageCoverage Checks whether every possible combination ofChecks whether every possible combination of Boolean sub expression occurs at least onceBoolean sub expression occurs at least once (2n), where “n” is the number of variables in a(2n), where “n” is the number of variables in a given branchgiven branch Test cases required for this method can beTest cases required for this method can be arrived at by using truth table of the conditionsarrived at by using truth table of the conditions Large number of test cases may be required forLarge number of test cases may be required for full multiple condition coveragefull multiple condition coverage
- 39. Testing Competency 39 Multiple Conditions Coverage – Test cases Multiple condition coverageMultiple condition coverage AgeAge SexSex MarriedMarried Test CaseTest Case IF-1IF-1 <25<25 MaleMale TrueTrue (1) 23 M T(1) 23 M T IF-1IF-1 <25<25 MaleMale FalseFalse (2) 23 M F(2) 23 M F IF-1IF-1 <25<25 FemaleFemale TrueTrue (3) 23 F T(3) 23 F T IF-1IF-1 <25<25 FemaleFemale FalseFalse (4) 23 F F(4) 23 F F IF-1IF-1 >=25>=25 MaleMale TrueTrue (5) 30 M T(5) 30 M T IF-1IF-1 >=25>=25 MaleMale FalseFalse (6) 70 M F(6) 70 M F IF-1IF-1 >=25>=25 FemaleFemale TrueTrue (7) 50 F T(7) 50 F T IF-1IF-1 >=25>=25 FemaleFemale FalseFalse (8) 30 F F(8) 30 F F IF-2IF-2 ** MaleMale TrueTrue (5)(5) IF-2IF-2 ** MaleMale FalseFalse (6)(6) IF-2IF-2 ** FemaleFemale TrueTrue (7)(7) IF-2IF-2 ** FemaleFemale FalseFalse (8)(8) IF-3IF-3 <=45, >=65<=45, >=65 ** ** ImpossibleImpossible IF-3IF-3 <=45,<65<=45,<65 ** ** (8)(8) IF-3IF-3 >45, >=65>45, >=65 ** ** (6)(6) IF-3IF-3 >45, <65>45, <65 ** ** (7)(7)
- 40. Testing Competency 40 Gray-Box TestingGray-Box Testing : An Introduction: An Introduction Blending of Structural and FunctionalBlending of Structural and Functional Testing methods throughout the entireTesting methods throughout the entire testing proceduretesting procedure Examines the activity of back-endExamines the activity of back-end components during test case executioncomponents during test case execution
- 41. Testing Competency 41 Thank you !Thank you !