Black box testing  Black box tests focus on the input/output behavior of the component  Black-box tests do not deal with the internal aspects of the component nor with the behavior or the structure of the components

Equivalence testing  Equivalence testing is a black box testing technique that minimizes the number of test cases

Equivalence testing  The possible inputs are partitioned into equivalence classes, a test case is selected for each class  The assumption of equivalence testing is that systems usually behave in similar ways for all members of a class

Equivalence testing  Equivalence testing consists of two steps:  identification of the equivalence classes  selection of the test inputs

Equivalence classes  Coverage: every possible input belongs to one of the equivalence classes  Disjointedness: no input belongs to more than one equivalence class  I.e., partition

Equivalence classes  Representation: if the execution demonstrates an error when a particular member of a equivalence class is used as input, then the same error can be detected by using any other member of the class as input.

Test cases  For each equivalence class, at least two pieces of data are selected  a typical input, which exercises the common case  an invalid input, which exercises the exception handling capabilities of the component

Boundary testing  Boundary testing is a special case of equivalence testing and focuses on the conditions at the boundary of the equivalence classes

Boundary testing  The assumption behind boundary testing is that developers often overlook special cases at the boundary of the equivalence classes  E.g.,  Empty strings  Year 2000 (millennium bug)  …

Int converter (again)  A function converts a sequence of chars in an integer number.  The sequence can start with a ‘-‘ (negative number).  The integer number must be in the range minint = to maxint =  The function signals an error if the sequence of chars is not allowed  The sequence must be <= 6 chars

Int converter (again) 1.Define equivalence classes, and related boundary condition 2.For each class, define at least one test case

Criterion  Input is a decimal number (well formed integer)  Valid: may start with –, no characters that are not digits  Invalid: …  Boundary: Starting “+”? Blanks?

Criterion  Length of string, number of characters  Valid: <= 6  Invalid: > 6  Boundary: 6, 0

Criterion  Range of number in output  Valid: = minint  Invalid: > maxint, < minint  Boundary: maxint, minint

Calendar BB Consider a method that returns the number of days in a month, given the month and year. public class MyGregorianCalendar { public static int getNumDaysInMonth(int x, int y){... } The month and the year are specified as integers. By convention, 1 represents the month of January, 2 the month of February, and so on. The range of valid inputs for the year is 0 to maxInt. 1.define equivalence classes, and related boundary condition 2.for each class, define at least one test case

Classes for month parameter  Three equivalence classes:  months with 31 days (i.e., 1, 3, 5, 7, 8, 10, 12)  months with 30 days (i.e., 4, 6, 9, 11)  February, which can have 28 or 29 days  Nonpositive integers and integers larger than 12 are invalid values

Classes for year parameter  Two equivalence classes:  leap years  non–leap years  Negative integers are invalid values

Selected valid inputs

Additional boundary cases

Equivalence classes definition  An interval condition will have classes for  Valid input within the interval  Invalid input less than the minimum  Invalid input greater than the maximum  Valid input close the boundaries  A single value condition will have classes for:  The valid value  Invalid values less than the value  Invalid values greater than the value

Equivalence classes definition  A discrete set condition will have classes for:  Each value in the set  A value not belonging to the set  A boolean value condition will have classes for:  TRUE value  FALSE value

Parallelogram  The function parallelogram(int x1, int x2, int x3, int x4, int y1, int y2, int y3, int y4) calculate the area of a parallelogram.

Parallelogram  Requirements  area is always strictly > 0  The parallelogram should stay in the first quadrant of the Cartesian plan  Define equivalence classes and tests

Criteria  Pair sides parallelism  Pair same sides length  Position (1 st quadrant)  Area > 0