Equivalence Testing
This method divides the input domain of a program into classes of data from which test cases can be derived. Equivalence partitioning strives to define a test case that uncovers classes of errors and thereby reduces the number of test cases needed. It is based on an evaluation of equivalence classes for an input condition. An equivalence class represents a set of valid or invalid states for input conditions.
Equivalence classes may be defined according to the following guidelines:
1. If an input condition specifies a range, one valid and two invalid equivalence classes are defined.
2. If an input condition requires a specific value, then one valid and two invalid equivalence classes are defined.
3. If an input condition specifies a member of a set, then one valid and one invalid equivalence class are defined.
4. If an input condition is Boolean, then one valid and one invalid equivalence class are defined.
• Test case Design for Equivalence partitioning
1. Good test case reduces by more than one the number of other test cases which must be developed
2. Good test case covers a large set of other possible cases
3. Classes of valid inputs
4. Classes of invalid inputs
Boundary testing
This method leads to a selection of test cases that exercise boundary values. It complements equivalence partitioning since it selects test cases at the edges of a class. Rather than focusing on input conditions solely, BVA derives test cases from the output domain also.
BVA guidelines include:
For input ranges bounded by a and b, test cases should include values a and b and just above and just below a and b respectively.
If an input condition specifies a number of values, test cases should be developed to exercise the minimum and maximum numbers and values just above and below these limits.
