Page 263 - Software and Systems Requirements Engineering in Practice

ç ç 3 O F T W A R E ç ç 3 Y S T E M S ç 2 E Q U I R E M E N T S ç % N G I N E E R I N G ç ) N ç 0 R A C T I C E

&IGURE SHOWS AN ABSTRACT USE CASE THAT IS EXTENDED BY VARIOUS
CONCRETE USE CASES THAT DESCRIBE THE POSSIBLE OPERATIONS OF THE MODELED
ABSTRACT USE CASE !N ABSTRACT USE CASE TYPICALLY HAS A GENERATED
ACTIVITY DIAGRAM AS SHOWN IN &IGURE WHICH EXPLICITLY MODELS THE
FACT THAT THERE ARE SEVERAL INDEPENDENT ALTERNATIVE WAYS TO TEST THE
ABSTRACT USE CASE
&IGURE IS AN EXAMPLE OF A CONCRETE USE CASE THAT SHOWS
ALTERNATIVE TEST PATHS OF DIFFERENT SCENARIOS TO TEST A PARTICULAR USE CASE
.OTE THERE ARE SEVERAL ACTIVITIES IN COMMON TO EACH TEST AND VARIOUS
ALTERNATIVE TEST PATHS 4HE EXAMPLE IN &IGURE ALSO INTRODUCES A TEST
VARIABLE AS A 5-, NOTE TO DECLARE DATA VARIATIONS )N THIS CASE TWO
VARIABLES ARE DECLARED /NE VARIABLE REPRESENTS THE OBJECT hPATIENTv
AND THE OTHER VARIABLE REPRESENTS THE OBJECT hIMAGEv TO BE USED %ACH
POSSIBILITY OF A PATIENT OR IMAGE IN THE EQUIVALENCE CLASSES RESULTS IN A
DIFFERENT TEST CASE ! CONSTRAINT IN THE NOTE REFLECTS THE RELATIONSHIP
BETWEEN THE SELECTED IMAGE AND THE SELECTED PATIENT
! TRANSITION IN THE ACTIVITY DIAGRAM CONTAINS A CONSTRAINT ON THE
DATA FOR ONE OF THE TEST PATHS )N THE EXAMPLE THIS SPECIFIES THAT
THE TEST PATH SHOULD USE A TEST DATA IMAGE WITH POOR IMAGE QUALITY
4HE CONSTRAINT LANGUAGE IS AN /BJECT #ONSTRAINT ,ANGUAGE /#,
SUBSET WITH LOGICAL OPERATORS @AND @OR @IMPLIES AND @XOR UNARY
OPERATOR @NOT AND RELATIONAL OPERATORS @ AND @ USING LITERAL
TERMS AND VARIABLE TERMS $URING TEST GENERATION VARIABLES ARE
BOUND TO ONE CHOICE OF AN EQUIVALENCE CLASS SUBJECT TO ALL THE
CONSTRAINTS IN THE GENERATED TEST PATH
%ACH ACTIVITY IN THE MODEL IS ANNOTATED WITH A DESCRIPTION AND
EXPECTED RESULT AND ALSO RELATED EXTERNAL REQUIREMENTS 4HESE
ANNOTATIONS CAN BE SPECIFIED IN THE DIAGRAM AS NOTES OR ASSIGNED AS
PROPERTIES USING A PROPERTY EDITOR ASSOCIATED WITH EACH ACTIVITY
&IGURE SHOWS AN EXAMPLE OF A PROPERTY EDITOR SHOWING THE
DESCRIPTION AND EXPECTED RESULT PROPERTY OF ONE ACTIVITY 0ROPERTIES
OF VARIABLE CHOICES AND PROPERTIES OF ACTIVITIES CAN BE SUBSTITUTED
INTO THE DESCRIPTIONS AND EXPECTED RESULTS TO CREATE THE GENERATED
TEST STEPS 4HE ACTIVITY DIAGRAM SHOWN IN &IGURE GENERATES NINE
TEST PATHS TO TEST THE USE CASE %ACH TEST PATH CAN BE REPLICATED TO CREATE
DIFFERENT TESTS WITH DIFFERENT PATIENT AND IMAGE DATA &OR EXAMPLE
HERE IS ONE TEST PATH

$ISPLAY WORK LIST
3ELECT DESIRED PROTOCOL
,OOK AT IMAGES [IMAGE] FOR [PATIENT]
)MAGE QUALITY CANNOT BE IMPROVED
3ET STATUS AS SUBOPTIMAL

-ORE COMPLEX EXAMPLES WILL INCLUDE MORE DECISIONS POINTS OR
DECISION POINTS THAT JOIN BACK AND SPLIT AGAIN TO OTHER DECISIONS