Test Case Specification
Systematic test preparation
TCS (Test Case Specification) is a proven effective tool for testing commercial software and technical software. This method combines the classic equivalence class analysis with several important extensions, such as the threshold value analysis. The tester first analyses all necessary data elements with which a program must be "fed" in order to generate certain calculations, outputs, etc. Then all desired results are specified.
Advantages of using SQS-TEST®/ Professional to determine test cases:
- Method and tool are one
- Secure because of completion check
- Transparency due to logical screen presentation
- Sound evaluations (test case list) among other things
Inputs and effects
Different inputs in the fields of a dialogue in the application
to be tested should normally result in differing effects.
The goal of a test is to check whether inputs have the expected
effects and whether these effects are unequivocal. It must
make a difference whether "Y" or "N" is
entered in a confirmation dialogue.
Grouping of the possible inputs
by means of equivalence class analysis
Since not all inputs that are actually possible can be tested
one by one, they have to be reduced.
There are a limited number of possible effects. Therefore,
when analysing a data structure (e.g. a dialogue) the following
procedure should be implemented: for every data element (input
field) the possible inputs are divided into groups of inputs
which have the same (equivalent) effect - into what is known
as equivalence or element classes. All inputs with the same
effect form an element class.
(The inputs "j", "J", "y", "Y" form a class with the same effect to indicate the affirmative in a dialogue, the inputs "n" and "N" a second (effect: the operation is abandoned); all other inputs (e.g. "x" or "5") would be invalid inputs (effect: error warning).)
The element classes may not intersect and together contain all inputs that are actually possible. The task of the test data definition later will be to select the element class which is most effective for the test from these equivalent inputs.
(In cases with a prescribed range, the highest and lowest values (threshold values) and an average value are frequently selected. In a confirmation field, the inputs "y" and "n" as well as "x", for example, could be used.)
Combinations of inputs
In many cases, inputs only have an unequivocal effect when
several inputs are taken together.
(e.g. for a seminar booking, the amount of discounts granted
(effects) could depend on the number of regis-tered participants
(e.g. <3; 3-9) and the number of days booked (1, 2 or 3)).
For these elements (fields), so-called dependencies are formed. Then all possible combinations are gener-ated by SQS-TEST®/Professional in an automated fashion, i.e. every element class of an element is linked up to all element classes of the other elements.
(In the above example, 2 combinations (element classes of the number of participants) x 3 (number of days) are generated.)
The combinations are analysed step by step - using a clear table presentation - until the effects are entirely and unequivocally allocated to the relevant input combinations. If different combinations have the same effect, they can be summarised; thus clarity is maintained through constant reduction.
Generating test cases
The final step is to generate test cases. A test case is a
complete, coherent result of possible inputs (known as an
input situation) connected to the expected effects. In a test
case, each element class is covered for one element (field);
each element class must occur in at least one test case. On
generation SQS-TEST®/Professional aims to cover all necessary
inputs with as few test cases as possible.
Results
The test cases determined form the basis for the generation
of test data; on generation at least one possible input must
be selected for each element class. The results of the Test
Case Specification can be presented in a wide range of formats,
e.g. in the form of a test case list, which provides a clear
master document for the inspection and generation of test
data.