2.3 Producing Robust Programs

In this module, you will learn how programs can be designed, tested, and refined so that they are robust, reliable, and easy to maintain. You will begin by exploring defensive design, including how programmers anticipate misuse, use authentication, and validate input to help programs deal with unexpected or invalid situations. You will also learn how subprograms, meaningful identifiers, indentation, and commenting improve the maintainability of program code.

Next, you will explore iterative and final testing, identify syntax and logic errors, and learn how normal, boundary, invalid, and erroneous test data are used to check different situations systematically. You will also construct test plans and use testing results to refine algorithms. By the end of the module, you will understand how defensive design, maintainable code, systematic testing, and refinement work together to produce programs that behave correctly in a wide range of situations.