Author: Haroon Khalil

It is now time to transform the test cases into automated JUnit tests. Writing those tests is mostly a mechanical task. The creative part is coming up with inputs to exercise the specific partition and understanding the correct program output for that partition. The automated test suite is shown in listings 2.3 through 2.7. They…

With the inputs, outputs, and boundaries properly dissected, we can generate concrete test cases. Ideally, we would combine all the partitions we’ve devised for each of the inputs. The example has four categories, each with four or five partitions: the str category with four partitions (null string, empty string, string of length 1, and string of length > 1), the open category with four…

Bugs in the boundaries of the input domain are common in software systems. As developers, we have all made mistakes such as using a “greater than” operator (>) where it should have been a “greater than or equal to” operator (>=). Programs with such bugs tend to work well for most provided inputs, but they…

We should find a way to prioritize and select a subset of inputs and outputs that will give us sufficient certainty about the correctness of the program. Although the number of possible program inputs and outputs is nearly infinite, some sets of inputs make the program behave the same way, regardless of the precise input…

An ad hoc exploration of what the method does may increase your understanding of it. I have noticed this when observing professional software developers writing test cases for methods they have never seen before (Aniche, Treude, and Zaidman, 2021). This step is more relevant when you did not write the code—if you wrote it, this…

Regardless of how your requirements are written (or even if they are only in your mind), they include three parts. First is what the program/method must do: its business rules. Second, the program receives data as inputs. Inputs are a fundamental part of our reasoning, as it is through them that we can test the…

Let’s start with an example. A new set of requirements comes in for you to develop. As soon as you begin to analyze the requirements, you identify a particular method you need to implement: a method that searches for substrings between two tags in a given string and returns all the matching substrings. Let’s call…

Software requirements are undoubtedly the most valuable artifact of software testing. By requirements, I mean any textual document that describes what a functionality should do. Requirements tell us precisely what the software needs to do and what it should not do. They describe the intricacies of the business rules that the software has to implement and…