Using%20query%20checking%20to%20generate%20test%20sequences

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Using query checking to generate test sequences

• Maryam Rashidian
• January, 2004

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Why use query checking to generate test sequences?

• Testing is our tool to uncover errors
• Test sets
• Coverage criteria
• Statement coverage
• Branch coverage
• Logical Expression coverage
• Test requirements
• Manual construction vs. automatic generation

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Using model checking to generate test sequences

• Counterexamples
• Trap properties
• Another alternative

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Temporal logic queries

• What is a query?
• A query is an expression obtained by replacing a
  single atomic proposition in a temporal logic
  formula by the symbol ?x, which is referred to as
  the placeholder of the query.
• Examples AG(?x), EF(?x ? p)
• What is the solution to the query?
• A propositional formula ? is a solution to a
  query ?, relative to state s of Kripke structure
  K, if K,s ? ??.
• Restricting atomic propositions
• Example AG(?xp,q)
• Using queries with multiple placeholders
• Example EF(?xcc ? EX?ycc)
• What is a witness?
• A path through the model that explains why the
  solution is as computed.

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TLQSolver
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SCR requirements model

• Four Variable Model

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SCR Constructs

• Mode class
• Mode
• Term
• Condition
• Event
• Input event _at_T or _at_F
• Conditioned event _at_T(c) WHEN d

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SCR tables

• Condition table
• Event table
• Mode transition table

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Case study Cruise Control System

• SCR requirements model for CCS
• Modeling CCS with SMV
• Finding queries for Logical Expression coverage
  criteria

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SCR requirements model for CCS

• SCR constructs
• Monitored variables
• Ignition
• Brake
• Accel
• Button
• Speed
• Mode class
• CC
• Off, Inactive, Cruise, Override
• Controlled variable
• Throttle

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SCR requirements

• SCR tables
• Mode transition table for CC

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SCR requirements

• SCR tables
• Event table for controlled variable Throttle

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Modeling CCS with SMV

• Variable definition
• Implementing mode class
• Implementing controlled variable Throttle
• Environmental assumptions

47 next(CC) case 48 CCOff (!(Ignition)
(next(Ignition))) Inactive 49 CCInactive
((Ignition) !(next(Ignition))) Off 50
CCInactive Ignition Running !(Toofast)
!(Brake) !(Accel) (!(Button b_Cruise)
(next(Button) b_Cruise)) Cruise 51
CCCruise ((Ignition) !(next(Ignition)))
Off 52 CCCruise (!(Toofast)
(next(Toofast))) Inactive 53 CCCruise
((Running) !(next(Running))) Inactive 54
CCCruise (!(Brake) (next(Brake)))
Override 55 CCCruise (!(Accel)
(next(Accel))) Override 56 CCCruise
(!(Button b_Off) (next(Button) b_Off))
Override 57 CCOverride ((Ignition)
!(next(Ignition))) Off 58 CCOverride
Ignition ((Running) !(next(Running)))
Inactive 59 CCOverride Ignition Running
!(Brake) !(Accel) !(Toofast) (!(Button
b_Resume) (next(Button) b_Resume)) Cruise
60 CCOverride Ignition Running !(Brake)
!(Accel) !(Toofast) (!(Button b_Cruise)
(next(Button) b_Cruise)) Cruise 61 1
CC 62 esac
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Finding queries for Logical Expression coverage
criteria

• Logical Expression coverage building
• Find predicates and clauses
• Find test sequences for
• Predicate Coverage (PC)
• Clause Coverage (CC)
• General Active Clause Coverage (GACC)
• Correlated Active Clause Coverage (CACC)
• Restricted Active Clause Coverage (RACC)

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Find predicates and clauses
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Predicate Coverage (PC)

• Two requirements
• Predicate should evaluate to TRUE
• Predicate should evaluate to FALSE

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Predicate Coverage (PC)
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Predicate Coverage (PC)
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Predicate Coverage (PC)
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Query checker limitations

• Do not accept Integer variables.
• Do not accept more than 4 or 5 placeholders,
  based on the type of the variable.

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Thank you

• Questions and Answers