Path Expressions in Software Testing Methodologies

Predicates and Relational Operators:

A predicate is implemented as a process, The outcomes of the process is a truth functional value

Predicates are based on relational operators of which the arithmetic relational operators are the most commonly used

Almost all programming languages have arithmetic relational operators

Using the primitive arithmetic relations, one can construct predicates as specified in requirements

Case Statements and Multi-valued Logics:

Predicates are not necessarily restricted to binary truth values

Multiway predicates such as switch can be notorious and most useful

Multi valued logics can be used to analyze predicate structures

Too many case statements require a lot of book keeping that probably affect the applicability of logic based testing

What Goes Wrong with Predicates:

The following are some for the several things that can go wrong with predicates especially when the predicated needs to be interrupted to express it as a predicate over input values

1. A wrong relational operator might be used

For example: > can be used in place of <=

2. The predicate expression of a compound predicate might be written wrong

For example: A+b instead of AB

3. The wrong operands are used

For example: A<X instead of A<Y

4. The processing that leads to the predicates is faulty

Logic based testing is useful against the first 2 types of bugs. For bugs 3 and 4, data flow testing will be more useful

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About Data Sciences by Venu

Hi, My name is Venugopala Chary and I'm Currently working as Associate Professor in Reputed Engineerng College, Hyderabad. I have B.Tech and M.tech in regular from JNTU Hyderabad. I have 11 Years of Teaching Experience for both B.Tech and M.Tech Courses.