Blackbox Testing Fra: CS Fall 2002

Blackbox Testing AKA Specification-Based Uses functional requirements to derive test cases Assumes errors include missing or improperly implemented functions No knowledge of implementation details F(x) x Result

Equivalence Partitioning Divide input domain into classes of data Single test case can cover all “equivalent” data elements Partitions consist of valid and invalid sets

Basic Rules Range of values: one valid, two invalid partitions Specific value: one valid, two invalid partitions Set member: one valid and one invalid partition Boolean value: one valid and one invalid class Other elements: use common sense and analysis

Invoice Specification Invoices are calculated using the following algorithm based on quantity of x and y: Item X sells for $5 and Item Y sells for $10 Invoice Total >=$200 get 5% discount Invoice Total >=$1000 get 10% discount Invoices that order more than 30 X items get a 5% discount

Invoice Equivalence Partitions X Classes: Y Classes: Invoice Total Classes: =0 30 Total < 200 Total >=1000 Total >=200, Total <1000

Border/Boundary Conditions Most errors happen at the boundary, so select test cases that test at and on each side of the boundary. X Boundaries: 30, 31, -1, 0 Y Boundaries:-1, 0 Invoice Total Boundaries: If there are specification limits on data sizes be sure to test at the limits i.e. program must store up to 100 numbers, then test at 100. What happens at 101??? 200, 199, 999,1000

Is Spec testing really hard? U.S. Army Personnel specification for holidays: Executive Order provided in the case of an employee whose work week varied from the normal Monday through Friday work week that Labor Day and Thanksgiving Day each were to be observed on the next succeeding workday when the holiday fell on a day outside the employee’s regular basic work week. Now, when Labor Day, Thanksgiving Day or any Monday holiday is outside the employee’s basic workweek, the immediately preceding workday will be his holiday when the non-workday on which the holiday falls is the second non-workday or the non-workday designated as the employee’s day off in lieu of Saturday. When the non- workday on which the holiday falls is the first non-workday or the non- workday designated as the employee’s day off in lieu of Sunday, the holiday observance is moved to the next succeeding workday.