A Research Of STFM Requirements Specification And Test Case Generation Method

Currently the description method of requirements in requirements engineering can mainlybeen divided into three categories: natural language, semi-formal methods and formal methods.Though the requirements described by natural language is easy to understand, suchrequirements specification has been prone ambiguous, so researchers have proposedsemi-formal methods, such as UML method. However, even if semi-method can avoid some ofthe problems in natural methods, it’s still not strict enough. Later, someone proposed the idea offormal requirements description methods, such as Z language, B method, TAM methods andTFM methods. Though these formal methods are not that easy to learn like natural language, itcan effectively avoid ambiguous, enhanced the accuracy. Therefore, the formal descriptionmethod of requirements has been one of the research hotspots in recent years. A goodrequirements specification can not only help the analyst understand the target system accurately,but also can be seen as the guideline for developers working in the software developmentprocess, and can be seen as a guidance in the software testing phase. In the combination ofrequirements engineering and software testing, many researchers have made a number ofmethods based on requirements to test.In this paper a formal description method of requirements specification based on tracefunction have been proposed, the final specification represents as some sets, the method isnamed as STFM(Set Trace Function Method). A test case generation method based on STFMspecification is also been proposed. Because the similarities between STFM and Cause-Effectdiagram method, this paper put forward the mapping rules from STFM requirementsspecification to the cause and effect relation, and then generates the decision table based oncause and effect relation, last generates the test case.The main work of this paper is as follows:1. The formal requirements specification method TAM (Trace Assertion Method) and TFM(Trace Function Method) were studied deeply. A new formal method STFM based on TFM have been proposed. STFM method represents the requirements of target system by setsthrough trace function.2. A description of STFM methods have been given in this paper. STFM specification is afour-tuple, every elements of the four-tuple is a special set. The four-tuple of STFMrespectively represents the statement set of input variables, the statement set of output variables,the statement set of access program and the trace function set of output variables. The writtenrules and the basic trace functions have been defined in this paper.3. A method of test case generation based on STFM requirements specification have beenproposed. The mapping rules form STFM specification to cause and effect relation are defined,and then generates the decision table according to the cause and effect relation, finally generatethe test case through decision table.4. Design and implement the test case generation system based on the method proposed bythis paper, and take a small library system as an instance.In this paper a requirements description method named STFM based on TFM and a testcase generation method based on STFM have been proposed, and we hope the work of thispaper can been a reference for the future research.