JNTU B.Tech III SOFTWARE TESTING METHODOLOGIES Previous Question Paper (August - 2022 - R16)

The taxonomy of bugs classifies software defects based on their origin, nature, and impact to facilitate systematic identification and resolution. The primary categories include:

• Requirements and Specification Bugs: Errors arising from incomplete, ambiguous, or incorrect requirements. These are often the most costly as they propagate through the entire development lifecycle.
• Design Bugs: Flaws in the architectural or detailed design, such as improper data structures, poor algorithm choice, or failure to handle specific edge cases.
• Coding Bugs: Implementation errors including syntax errors, logic errors, loop termination issues, or improper variable initialization.
• Interface Bugs: Issues occurring at the boundaries between different modules, subsystems, or external APIs, often due to mismatched parameter types or communication protocols.
• Testing Bugs: Errors in the test suite itself, such as incorrect test data, flawed test scripts, or failure to account for environmental dependencies.

In path testing, a path predicate is a logical condition or a set of conditions that must be satisfied for a specific path through a program to be executed. These predicates are typically derived from decision points like if-statements, loops, or switch cases. A path is defined by the sequence of branches taken, and the path predicate is the conjunction of all predicates encountered along that path.

An achievable path is a path for which there exists at least one set of input data that satisfies all the predicates along that path, allowing the program to actually execute that sequence of statements. A path is unachievable (or infeasible) if the conjunction of its predicates is logically inconsistent (e.g., x > 5 AND x < 2), meaning no input can satisfy the conditions required to traverse it.

The process of determining achievability involves:

1. Identifying all predicates along the path.
2. Formulating the path predicate expression as a logical conjunction.
3. Solving the resulting system of constraints using techniques like symbolic execution or constraint solvers.
4. If the system is satisfiable, the path is achievable; otherwise, it is infeasible, which may indicate dead code or flawed logic in the program design.