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SUMMARY:Testing and fault localization in constraint programs - Lazaar Nad
 jib\, IRISA
DTSTART:20100915T130000Z
DTEND:20100915T140000Z
UID:TALK26199@talks.cam.ac.uk
CONTACT:Microsoft Research Cambridge Talks Admins
DESCRIPTION:Constraint programs such as those written in high-level modeli
 ng languages (e.g.\, OPL\, ZINC\, or COMET) must be thoroughly verified be
 fore being used in applications. Detecting and localizing faults is theref
 ore of great importance to lower the cost of the development of these cons
 traint programs. We propose a general framework of constraint program deve
 lopment which supposes that a first declarative and simple constraint mode
 l is available from the problem specifications analysis. Then\, this model
  is refined using classical techniques such as constraint reformulation\, 
 surrogate and global constraint addition\, or symmetry- breaking to form a
 n improved constraint model that must be thoroughly tested before being us
 ed to address real-sized problems. Firstly\, we think that most of the fau
 lts are introduced in this refinement step and propose a process which tak
 es the first declarative model as an oracle for detecting non-conformities
 . We derive practical test purposes from this process to generate automati
 cally test data that exhibit non-conformities. We implemented this testing
  approach in a new tool called CPTEST. Secondly\, we enhance this framewor
 k to introduce automatic fault localization in constraint programs. Our lo
 calization approach is based on constraint relaxation to identify the cons
 traint that is responsible of a given fault. CPTEST is henceforth able to 
 automatically localize faults in optimized OPL programs. We provide empiri
 cal evidence of the effectiveness of testing and localizing approaches on 
 classical benchmark problems\, namely Golomb rulers\, n-queens\, social go
 lfer and car sequencing. 
LOCATION:Small public lecture room\, Microsoft Research Ltd\, 7 J J Thomso
 n Avenue (Off Madingley Road)\, Cambridge
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