Here are some notes about grouping testcases
The basis is analyzed to determine what should be tested. It must be determined how the eindividual requirements and the test classes relate to each others. Thus, it is possible to determine the coverage of the requirements by the tests.
The expected results should be determined before executing the test cases. Otherwise, it often happends that an incorrect result is interpreted as correct, thus missing detection of a failure.
Grouping
Testcases should be grouped in such way that a whole scenario of testcases is executed. Such a test sequene is documented in the test procedure spesification (or test instructions). The document commonly groups the testcases by topics or by test objectives.
How to derive the test classes to be grouped
- For every input data element that should be tested, , the domain of all possible input should be determined.
- This domain is then partitioned into equivalent classes.
- First, the sub-domain of correct inputs is found. This is the equivalent class of all correct input values.
- The test object should process these values according to the specification.
- The values outside of this domain are seen as equivalence classes with incorrect input values. for these values as well, it must be tested how well the test object behaves.
The next step is to refine the equivalent classes.
Partitioning into equivalence classes and selecting the representatives should be carefully done. the probability of failure detection is highly dependent upon the quality of the partitioning, as well as which test cases are executed.
The best test cases are those verifying the boundaries of the equivalence classes. There are often misunderrstandings or inaccurancies in the requirenments at these spots, because our natural languare is not precise enough to accurately define the limits of equivalence classes.
To clarify the procedure for building equivalence classes, all possible equivalence classes for an integer inout value are to be identified.
Tips:
- An experienced tester will always include a test case with a floating-point number in order to determine if the program rounds the number and continues with the numbered integer.
- Zero is an interesting value, it often leads to failures (BC / AC). Therefore, it is often interesting to test.