1. April 1,200291.3913 R McFadyen1 A Traditional Software Development Process Unit test Integration test System test Detailed design Architectural design Analysis Requirements analysis Business modeling process Business results

2. April 1,200291.3913 R McFadyen2 Black Team Peopleware: Productive Projects and Teams by Tom Demarco and Timothy Lister Ch 19: The Black Team "legendary" Black Team at IBM in 60’s a particularly effective testing team the best testers at the company testers delighted in finding new ways to break software programmers dreaded having their software go through Black Team testing promoted themselves by dressing all in black the spirit of the Black Team has survived

3. April 1,200291.3913 R McFadyen3 Testing Unit testing Equivalence classes Boundary classes Black-box testing White-box testing Integration testing System testing Object-oriented testing

4. April 1,200291.3913 R McFadyen4 Black-box Testing A blackbox test is one that focuses on the input/output behaviour of a component without considering its implementation The system being tested is a black box, whose behaviour is determined by studying its inputs and outputs aka functional testing since it is concerned with functionality and not implementation Equivalence testing Boundary testing

5. April 1,200291.3913 R McFadyen5 Equivalence testing A technique to minimize the number of test cases An equivalence class is a set of tests with common characteristics A test case is selected for each class We use our domain knowledge to generate equivalence classes example: suppose a method returns the number of days in a month, given the month and year. –When we consider months, we could arrive at 3 equivalence classes: months with 31 days months with 30 days months with 28 or 29 days –When we consider years, we have two equivalence classes: leap years and non-leap years –Combining, we have 6 equivalence classes

6. April 1,200291.3913 R McFadyen6 Six equivalence classes Equivalence class Input values month year 31 day month, non-leap year 7 1901 31 day month, leap year 7 1904 30 day month, non-leap year 6 1901 30 day month, leap year 6 1904 28/29 day month, non-leap year 2 1901 28/29 day month, leap year 2 1904

7. April 1,200291.3913 R McFadyen7 Boundary testing We focus on the boundary conditions of equivalence classes Rather than selecting any element in an equivalence class, boundary testing requires that elements be selected from the “edges” Example In general, years that are multiples of 4 are leap years; years that are multiples of 100 are not leap years, unless they are multiples of 400. 2000 is a leap year, but 1900 is not For Year, 2000 and 1900 are good boundary cases 0 and 13 would be good boundary cases for month

8. April 1,200291.3913 R McFadyen8 Ten equivalence classes Equivalence class Input values month year 31 day month, non-leap year 7 1901 31 day month, leap year 7 1904 30 day month, non-leap year 6 1901 30 day month, leap year 6 1904 28/29 day month, non-leap year 2 1901 28/29 day month, leap year 2 1904 Leap year divisible by 400 2 2000 Non-leap year divisible by 100 2 1900 Non-positive invalid month 0 1904 positive invalid month 13 1904

9. April 1,200291.3913 R McFadyen9 Whitebox testing Boundary and Equivalence testing: if you know the algorithm, you will be able to generate more test classes. Path testing: A whitebox testing technique based on flow of control Construct a flow graph for Cyclomatic Complexity The minimum number of tests necessary to cover all edges is the number of independent paths through the flow graph Design test cases such that each transition is traversed at least once - examine each condition and select an input for the true branch and another for the false branch

10. April 1,200291.3913 R McFadyen10 public class MonthOutOfBounds extends Exception {…}; public class YearOutOfBounds extends Exception {…}; class MyGregorianCalendar { public static boolean isLeapYear(int year) { boolean leap; if (year%4) { leap = true; } else { leap = false; } return leap; } public static int getNumDaysInMonth(int month, int year)... A (faulty) Java implementation of getNumDaysInMonth() See next slide What’s wrong here?

11. April 1,200291.3913 R McFadyen11 public static int getNumDaysInMonth(int month, int year) throws MonthOutOfBounds, YearOutOfBounds { int numDays; if (year < 1) { throw new YearOutOfBounds(year); } if (month==1 || month==3 || month==5 || month==7 || month==10 || month==12) { numDays = 32; } else if (month==4 || month==6 || month==9 || month==11) { numDays = 30; } else if (month == 2) { if (isLeapYear(year)) { numDays = 29; } else { numDays = 28; } else { throw new MonthOutOfBounds(month); } return numDays; }... } What’s wrong here?

12. April 1,200291.3913 R McFadyen12 Flow graph - as a UML activity diagram year out of bounds month out of bounds n = 32 n = 30 n = 28 n = 29 [year < 1] [month in {1,3,5,7,10,12}] [month in {4,6,9,11}] [month=2] [leap year]

13. April 1,200291.3913 R McFadyen13 UML activity diagram (flow graph) year out of bounds month out of bounds n = 32 n = 30 n = 28 n = 29 [year < 1] [month in {1,3,5,7,10,12}] [month in {4,6,9,11}] [month=2] [leap year] 1 2 3 4 5 6 We can walk through the flow graph and generate 6 tests to ensure each transition is traversed

14. April 1,200291.3913 R McFadyen14 UML activity diagram (flow graph) year out of bounds month out of bounds n = 32 n = 30 n = 28 n = 29 [year < 1] [month in {1,3,5,7,10,12}] [month in {4,6,9,11}] [month=2] [leap year] 1 2 3 4 5 6 We can walk through the flow graph and generate 6 tests to ensure each transition is traversed Year=0; month=7 Year=1999; month=7 Year=1999; month=6 Year=2000; month=2 Year=1999; month=2 Year=2000; month=0

15. April 1,200291.3913 R McFadyen15 What is the flow graph for isLeapYear()? What tests can we generate from it? isLeapYear() Which tests, of all the tests we’ve outlined, will actually help us find the problems with these two methods?

16. April 1,200291.3913 R McFadyen16 Another White-box Testing Example FindMean(float Mean, FILE ScoreFile) … What is the flow graph for FindMean? What is the CC? What tests can we generate from the CC … to know all paths have been executed?

17. April 1,200291.3913 R McFadyen17 /*Read in and sum the scores*/ Another White-box Testing Example FindMean(float Mean, FILE ScoreFile) { SumOfScores = 0.0; NumberOfScores = 0; Mean = 0; Read(ScoreFile, Score); while (! EOF(ScoreFile) { if ( Score > 0.0 ) { SumOfScores = SumOfScores + Score; NumberOfScores++; } Read(ScoreFile, Score); } /* Compute the mean and print the result */ if (NumberOfScores > 0 ) { Mean = SumOfScores/NumberOfScores; printf("The mean score is %f \n", Mean); } else printf("No scores found in file\n"); }

18. April 1,200291.3913 R McFadyen18 Prepare for Flow Graph FindMean (FILE ScoreFile) { float SumOfScores = 0.0; int NumberOfScores = 0; float Mean=0.0; float Score; Read(ScoreFile, Score); while (! EOF(ScoreFile) { if (Score > 0.0 ) { SumOfScores = SumOfScores + Score; NumberOfScores++; } Read(ScoreFile, Score); } /* Compute the mean and print the result */ if (NumberOfScores > 0) { Mean = SumOfScores / NumberOfScores; printf(“ The mean score is %f\n”, Mean); } else printf (“No scores found in file\n”); } 1 2 3 4 5 7 6 8 9

19. April 1,200291.3913 R McFadyen19 Constructing the Logic Flow Diagram 4 3 2 1 5 6 78 9 CC = 11-9+2 = 4 1, 2, 6, 8, 9 1, 2, 6, 7, 9 is not possible 1, 2, 3, 4, 5, 2, 6, 7, 9 1, 2, 3, 4, 5, 2, 6, 8, 9 is not possible 1, 2, 3, 5, 2, 6, 8, 9 1, 2, 3, 5, 2, 6, 7, 9 is not possible ok Note: If node 4 is included then node 7 must be included These 3 tests cover all paths! We didn’t need 4!

20. April 1,200291.3913 R McFadyen20 Testing Testing tools can count the number of times instructions are executed. This is examined for completeness – that all paths have been executed. How would knowledge of the algorithm (the code) affect your choices of equivalence classes and boundary classes? Suppose you are testing a search method. What equivalence and boundary classes would you decide on? Suppose you know the search is a binary search and not a simple selection search … this should affect your classes

21. April 1,200291.3913 R McFadyen21 Class model for a testing system? is caused by ** Test case FailureFaultError Test suite is caused by * * CorrectionComponent Test stub Test driver exercises is revised by findsrepairs * ** * * * 1…n * *

22. April 1,200291.3913 R McFadyen22 Testing Example: Suppose we have a search module to test. We know: –the list, elt, must have at least one element –if the element, key, is found, found will be true and elt[L] = key –if the key is not found, found will be false How do we structure, or organize, our test cases?

23. April 1,200291.3913 R McFadyen23 Black-box Testing Example (continued): How do we structure, or organize, our test cases? We have two types of searches: successful and unsuccessful. So, we can partition our search test cases into two classifications: found and not found When it comes to lists of elements, we know that lists of length 1, are special cases or boundary points. So, we should have 2 partitions of lists: length 1, and length of more than one. When an element is searched for, it can be found in boundary positions. So, we can should have 3 partitions: found at the start, found at the end, and then we should include where it is found in the middle.

24. April 1,200291.3913 R McFadyen24 Black-box Testing FoundNot Found List of 1 element Example (continued): combining the partitions List of >1 element In 1st position In last position In middle position List of >1 element 12 3 4 5 6

25. April 1,200291.3913 R McFadyen25 Black-box Testing 55 44 Example (continued): sample tests for the 6 partitions 55 33 88 44 22 33 6 77 88 44 33 66 77 88 22 22 55 88 66 77 1 2 3 4 5 6 55true, 1 55false, ? 55true, 1 44true, 6 77true, 3 99false, ? Outputs Found, L Inputs List Key

26. April 1,200291.3913 R McFadyen26 White-box Testing Tests are derived from knowledge of the software’s construction aka structural, glass-box, or clear-box testing Tester analyzes the code, the algorithm, to derive test data

27. April 1,200291.3913 R McFadyen27 White-box Testing Example: suppose we are examining an algorithm that searches an ordered list for a specific value in Key. On examination we see it’s a binary search and we see that it really treats the List as having 3 sections: elements < mid mid- point elements > mid

28. April 1,200291.3913 R McFadyen28 White-box Testing :We can use this knowledge to further refine our partitioning - we need to test for where the Key we are looking for is at the boundary points for these partitions. elements < mid mid- point elements > mid We’ll add two more tests

29. April 1,200291.3913 R McFadyen29 White-box Testing Example: 55 44 55 66 77 88 99 22 33 44 50 56 61 76 1 2 3 4 5 6 55true, 1 55false, ? 55true, 1 50true, 4 76true, 7 44true, 3 Outputs Found, L Inputs List Key 22 33 44 50 56 61 76 7 56true, 5 22 55 88 66 77 8 99false, ?

30. April 1,200291.3913 R McFadyen30 Integration Testing Combine components into a system Typical strategy is bottom-up or top-down Top-down –related to top-down development –development starts with high-level components and works down. –Incomplete modules are stubs with the interface, but little or no functionality. – As top level is programmed and tested, the sub- components are implemented and tested, … Bottom-up –... (requires more test drivers) Big-bang … difficult to pinpoint errors

31. April 1,200291.3913 R McFadyen31 Object-Oriented Integration Testing Class testing more than one method/operation statechart diagrams transitions … events that can cause a change in state must be tested Subclasses Subclasses should be tested for inherited operations Overridden operations must be tested Integration testing (top? bottom?) Collaboration testing Test objects for support of system events and Use Cases Test significant object collaborations Note on page 311: suggests implementation from least- coupled to most-coupled

32. April 1,200291.3913 R McFadyen32 System Testing Test all subsystems as a single system Performance testing –Stress test –Volume test –Security test –Recovery test –… Acceptance testing –Benchmark test for typical conditions –Shadow test –Installation test –Documentation test –…