Method and system for describing predicates in disjuncts in procedures for test coverage estimation

• US 6,697,961 B1
• Filed: 09/15/2000
• Issued: 02/24/2004
• Est. Priority Date: 09/17/1999
• Status: Expired due to Fees

• Current Assignee: Nortel Networks Corporation
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Sumar, Harry M., Galter, Dmitri, Maximov, Andrei V., Sazanov, Juri L., Burdonov, Igor B., Petrenko, Alexander K., Kossatchev, Alexander S.
• Primary Examiner(s): Iqbal, Nadeem
• Application Number:
  US09/663,726
• Time in Patent Office: 1,257 Days
• Field of Search: 714/26, 714/38, 714/39, 714/47, 714/32, 714/33, 714/37, 714/51, 714/43, 714/45, 716/2, 716/4
• US Class Current: 714/26
• CPC Class Codes: G06F 11/3684 for test design, e.g. generating new test cases

Abstract

To estimate test coverage of procedure testing with functional specification of a procedure, predicates in functional branches in the procedure are described as logic expressions. The logic expressions of predicates are added to logic expressions of pre-condition of the procedure. Based on the logic expressions, functions of the functional specification of the procedure are generated and coverage during the procedure testing is estimated. In an embodiment, Disjunct Normal Form (DNF) is generated using short logic which omits calculation of an operand when another operand defines the result of the calculation. In another embodiment, Full Disjunct Normal Form (FDNF) is generated using three-sign logic.

Claims

1. A method for estimating test coverage of procedure testing with a functional specification of a procedure, the method comprising steps of:

describing predicates in functional branches of the procedure as logic expressions by calculating the logic expression of dependencies using short logic which omits calculation of an operand when another operand defines the result of the calculation;

adding the logic exspressions of predicates to logic expressions of at least a pre-condition of the procedure;

generating, based on the logic expressions, functions of the functional specification of the procedure; and

estimating coverage during the procedure testing.

2. The method as claimed in claim 1, wherein

the step of generating automatically generates Disjunct Normal Form (DNF).

3. The method as claimed in claim 1, wherein the step of describing describes values of the predicates using three-sign logic;

and

the step of generating automatically generates Full Disjunct Normal Form (FDNF).

4. A method for constructing Disjunct Normal Form (DNF) from a functional specification of a procedure for estimation of test coverage of procedure taking with the functional specification of the procedure, the method comprising the steps of:

describing dependencies between predicates in disjuncts in the procedure as logic expressions by calculating the logic expression of dependencies using short logic which omits calculation of an operand when another operand defines the result of the calculation;

adding the logic expressions of dependencies to logic expressions of at least a pre-condition of the procedure; and

generating, based on the logic expressions, the DNF of the functional specification of the procedure.

5. The method as claimed in claim 4, wherein the step of describing comprises steps of:

determining dependencies of pairs of predicates;

writing dependency as implication for a pair when predicates included in the pair are dependent; and

constructing conjunction of the implications.

6. The method as claimed in claim 5, wherein the step of writing comprises a step of calculating the implication in short logic which omits calculation of one predicate when another predicate defines the result of the calculation.

7. The method as claimed in claim 5, wherein the step of constructing comprises a step of calculating the conjunction in long logic which calculates values of both predicates.

8. The method as claimed in claim 5, wherein the step of describing further comprises a step of linking implication of a composite dependency by a long conjunction.

9. The method as claimed in claim 5, wherein the step of describing further comprises a step of deleting a pair when predicates included in the pair are independent.

10. A method for describing dependencies between predicates for construction of Disjunct Normal Form (DNF) from a functional specification of a procedure for estimation of test coverage of procedure testing with the functional specification of a procedure, the method comprising steps of:

describing dependencies between predicates in disjuncts in the procedure as logic expressions by

determining dependencies of pairs of predicates;

writing dependency as implication for a pair when predicates included in the pair are dependent; and

constructing conjunction of the implications.

11. The method as claimed in claim 10, wherein the step of writing comprises a step of calculating the implication in short logic which omits calculation of one predicate when another predicate defines the result of the calculation.

12. The method as claimed in claim 10, wherein the step of constructing comprises a step of calculating the conjunction in long logic which calculates values of both predicates.

13. A system for describing dependencies between predicates for construction of Disjunct Normal Form (DNF) from a functional specification of a procedure, the system comprising:

a dependency handler for determining dependencies of pairs of predicates in disjuncts in the procedure, and for adding logic expressions of dependencies to logic expressions of precondition of the procedure;

a short logic calculator for calculating implication as logic expression of dependency of a pair of predicates when the predicates included in the pair are dependent; and

a long logic calculator for calculating a conjunction of the implications.

14. The system as claimed in claim 13, wherein the short logic calculator calculates the implication in short logic which omits calculation of one predicate when another predicate defines the result of the calculation.

15. The system as claimed in claim 13, wherein the long logic calculator calculates the conjunction in long logic which calculates values of both predicates.

16. The system as claimed in claim 13, wherein the long logic calculator further calculates long conjunction to link implication of a composite dependency.

17. The system as claimed in 13, wherein the dependency handler deletes a pair when predicates included in the pair are independent.

18. A method for constructing Full Disjunct Normal Form (FDNF) from a functional specification of a procedure, the method comprising steps of:

describing values of predicates using three-sign logic as logic expressions of predicates in disjuncts in a procedure, the three-sign logic including a value indicating a value of a predicate which is inaccessible;

adding the logic expressions of predicates to logic expressions of precondition of the procedure; and

generating, based on the logic expression, the FDNF of the functional specification of the procedure.

19. The method as claimed in claim 18, wherein the describing step comprises steps of:

determining if predicates are accessible;

assigning the value indicating an inaccessible predicate to inaccessible predicates;

calculating values of accessible predicates; and

assigning the calculated values to description of the accessible predicates.

20. The method as claimed in claim 19, wherein the describing step flyer comprises a step of comparing the resultant array to arrays describing disjuncts to locate equality of elements to calculate coverage criterion.

21. A method for describing values of disjuncts in a predicate for construction of lull Disjunct Normal Form (FDNF) from functional specification of a procedure for estimation of test coverage of procedure testing with functional specification of a procedure, the method comprising steps of:

building an array of description of a disjunct, the array having elements corresponding to predicates;

initializing all elements in the array to indicate that values of predicates are inaccessible;

calculating values of predicates which are accessible; and

assigning the calculated values to elements in the array that correspond to the accessible predicates.

22. The method as claimed in claim 21 further comprising a step of comparing the resultant array to arrays describing disjuncts to locate equality of elements to calculate coverage criterion.