Test Case Design Method-Boundary Value Analysis

The Boundary Value Analysis method supplements the equivalence classification method.

(1) Considerations of the Boundary Value Analysis Method:

Long-term testing experience tells us that a large number of errors occur on the boundary of the input or output range, rather than within the input and output range. therefore, you can design test cases for various boundary conditions to identify more errors.

When using the Boundary Value Analysis Method to Design test cases, the boundary condition should be determined first. generally, the boundary of the input and output equivalence classes is the boundary that should be tested. select a value equal to or greater than or less than the boundary as the test data, instead of a typical value or any value in the equivalence class as the test data.
(2) principles for selecting test cases based on the Boundary Value Analysis Method:

1) if the input condition specifies the value range, take the value that has just reached the boundary of this range and the value that has just exceeded the boundary of this range as the test input data.

2) If the input condition specifies the number of values, use the maximum and minimum numbers, one less than the minimum number, and one more than the maximum number as the test data.

3) use the previous Principle 1 according to each output condition in the Specification Description ).

4) apply the preceding principles based on each output condition in the Specification Description. 2 ).

5) IfProgramIf the input or output fields are ordered sets, the first and last elements of the set should be selected as the test case.

6) if an internal data structure is used in the program, select the value at the boundary of the internal data structure as the test case.

7) analyze the specifications to find other possible boundary conditions.