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In this chapter 13, you will: Understand why data flow criteria have been designed and used, recognize and distinguish basic DF criteria, understand how the infeasibility problem impacts data flow testing, appreciate limits and potential practical uses of data flow testing. | Data flow testing c 2007 Mauro Pezze Michal Young Ch 13 slide 1 Motivation Middle ground in structural testing - Node and edge coverage don t test interactions - Path-based criteria require impractical number of test cases And only a few paths uncover additional faults anyway - Need to distinguish important paths Intuition Statements interact through data flow - Value computed in one statement used in another - Bad value computation revealed only when it is used Learning objectives Understand why data flow criteria have been designed and used Recognize and distinguish basic DF criteria - All DU pairs all DU paths all definitions Understand how the infeasibility problem impacts data flow testing Appreciate limits and potential practical uses of data flow testing c 2007 Mauro Pezze Michal Young Ch 13 slide 2 Data flow concept Value of X at 6 could be computed at 1 or at 4 Bad computation at 1 or 4 could be revealed only if they are used at 6 1 6 and 4 6 are def-use DU pairs - defs at 1 4 - use at 6 c 2007 Mauro Pezze Michal Young Ch 13 slide 4 Terms DU pair a pair of definition and use for some variable such that at least one DU path exists from the definition to the use X . is a definition of X . X . is a use of X DU path a definition-clear path on the CFG starting from a definition to a use of a same variable - Definition clear Value is not replaced on path - Note - loops could create infinite DU paths between ggi a def and a use c 2007 Mauro Pezze Michal Young Ch 13 slide 5 Adequacy criteria All DU pairs Each DU pair is exercised by at least one test case All DU paths Each simple non looping DU path is exercised by at least one test case All definitions For each definition there is at least one test case which exercises a DU pair containing it - Every computed value is used somewhere Corresponding coverage fractions can also be SOFTWARE TEỈTI.S d of 1 nod AND ANALYSIS c 2007 Mauro Pezze Michal Young Ch 13 slide 7 Definition-clear path c 2007 Mauro Pezze Michal .
