Software Testing Principles

I am writing in response to the blog post at titled “7 Software Testing Principles: Learn with Examples”.

This blog post highlights some useful general guidelines for software testing. In order to write effective test cases, it is important to follow some logical approach toward determining what to test for and how to test it, and this is a guide that describes such a set of principles to follow that are well suited to capture the logic involved in software testing.

The first principle is that exhaustive testing is not possible. I am not sure I believe this. In general it is useful to assume there exists no perfect test, but for simple enough applications where the number of possible interactions are enumerable, I would think that it would be possible to achieve exhaustive testing, much like an exhaustive proof, where every possible path is covered and verified. Maybe I am missing the implausible event that the test is correct but the computer running the tests is corrupted in such a way that certain tests are not run. This is relevant to a point made in this area, which is risk assessment.

The second and third principles make similar points. Always running the same tests will eventually not cover certain issues. If all of the same methods for testing are always applied exactly the same, then eventually there will be some scenario which the particular method is not suited for, and it will miss something. This leads into the later principles: the absence of a failure is not proof of success, and context is important. Developing tests suited for the particular application is necessary to ensure the correlation between tests passing and the program functioning correctly, and just because every test passed does not mean the program is going to work perfectly.

This set of software testing principles can be summarized in a few basic points. Develop test cases that are well suited specifically for the application that is being tested, consider the risk of certain operations causing a failure, and do not assume that everything works perfectly just because every test case passed.


Software Engineer Qualification

I am writing in response to the blog post at titled “Five programming problems every Software Engineer should be able to solve in less than 1 hour”.

This blog post shares a story about a history of people who apply for the position of a software engineer and claim some loosely related skills without actually having any chance of understanding or performing the job. The frustration of the author is expressed, and the author lists five programming tasks to disqualify any supposed “software developer” who would not be able to complete them in under an hour. I attempted them myself and they only took five minutes.

I am not sure what motivation people have to apply for a job that they are in no way capable of performing, but the author of this blog post seems to be fed up with how common it is. Supposedly, though, people who do not know what programming is are attempting to become software engineers.

I think that the list of five programming problems and the time constraint of one hour is a generous filter to sort out all of the people who have never written a program in any language ever before. It certainly would not be enough to qualify for the position of a software engineer, but that is not what the problems are meant to indicate upon fulfillment, it is simply what they are meant to reject upon failure. Somebody who claims to be a “developer” and fails to accomplish these simple tasks should revisit their resume.

The problems themselves are very basic. Find the sum of some numbers using loops or recursion, combine elements in two arrays, calculate Fibonacci numbers, and the last two problems are more peculiar but still simple demonstrations of basic problem solving. It should be evident in much less than an hour whether a person is capable of solving them, and any experienced software engineer should only need ten minutes.

The blog post acknowledges some feedback about the last two problems that are a bit less conventional than the others, but I think that the ability to solve unconventional problems is important, and I think anyone who writes code in something besides a markup language or an object notation could solve them.