TesterHQ - The Evil Tester Blog Aggregator

Mar 11, 2002 - 15 minute read - Evil Tester Rants

An Actor's Life for me

…Meyerhold’s bio-mechanical actor said, “I make these movements because I know that when I make them what I want to do can most easily and directly be done.” [1] All quotations in this article are from “The Actor’s Ways and Means”, Michael Redgrave, William Heinemann Ltd, 1953 More for amusement than a desire to educate myself further in the ways of testing, I picked up a copy of Michael Redgrave’s lectures on the actor’s craft “The Actor’s Ways and Means”.

Feb 13, 2002 - 10 minute read - Evil Tester Rants

Finding Faults with Software Testing

There are many universal statements that a tester will come across in the course of their career, some true “Testing can only prove the presence of faults and not their absence”, and some false “Developers must not test their own code” Such statements may well be paraphrased quotes, the original source may not be known or presented, and the quote may be taken out of its original context. But they will be one common form of the phrase that exists in the industry’s shared consciousness.

Feb 8, 2002 - 3 minute read - Essays Evil Tester

Test Conditions

Test Conditions are statements of compliance which testing will demonstrate to be either true or false. These are (in effect) test requirements. Conditions serve different purposes. Some conditions will act as the audit reason for a particular test case e.g. The user must be able to create a flight. The tester will create a test which creates a flight, obviously there are more attributes to this case than this - what type of flight, what type of user, fully booked, partially booked, etc.

Feb 7, 2002 - 1 minute read - Essays Evil Tester

Process Improvement

The simplest way to improve a process is to analyse the errors that it lets slip through. For every error not found by one of the previous quality control processes, ask, is there a strategy that could have been applied to one of the existing models that would have created a test case that could have identified the error. If the answer is yes then it may well have slipped through because timescales or staffing levels forced your hand and you simply didn’t have the time to apply that strategy to that model, or the risk of not applying it was deemed low.

Feb 6, 2002 - 1 minute read - Essays Evil Tester

Error Guessing

Error Guessing is described in ‘Testing Computer Software’ by Cem Kaner [1]: “For reasons that you can’t logically describe, you may suspect that a certain class of tests will crash the program. Trust your judgment and include the test.” This quote suggests to me that there is an informal model in the tester’s head and that the subconscious is applying a strategy to the model which the tester is unaware of.

Feb 5, 2002 - 3 minute read - Essays Evil Tester


Testing is exploration. In a mature testing organisation the expedition is well planned, and staffed with seasoned explorers. The planning will be done around a number of maps of the territory to be explored. Some maps will show different levels of detail - to show all the detail on one map would confuse the issue, so one map will identify areas of population, one will provide information of season rainfall statistics etc.

Feb 4, 2002 - 1 minute read - Essays Evil Tester

Testing and Modelling

In order to test a model we have to have some way of recognising the success or failure of a test, our test must have a goal, it must have a reason for existing. That reason is inherent in the model from which the test is derived. This means that it is difficult to use a model to test itself. In software development this is typically not a problem, we rarely use the source code as the only model when testing the source code.

Feb 3, 2002 - 2 minute read - Essays Evil Tester

Checking the model

Do we want to produce programs that are fault free or do we want to produce programs that allow people to do what they want to do in a quality manner? Ideally I’d prefer both, but humans make mistakes so we should aim for a product that functions in a quality manner. When we achieve that we do it by assuring ourselves of the quality of the models in the software development process as they are produced, and before they are fed into a downstream process that will build new models using the information contained in those models.

Feb 2, 2002 - 2 minute read - Essays Evil Tester

Modelling the development process

Software development tries to create a product. It does this by engaging in a number of processes (requirements, design, coding, etc.). Each of these processes will create a model that will either be the final product or an input to a follow on process. The best example of this is one of the popular life cycle models: waterfall or V model. There are constraints on the construction of a product; we need it in X days, it must only cost Y thousand, and you only have Z staff members.

Feb 1, 2002 - 2 minute read - Essays Evil Tester

On Modelling

“A map is not the territory it represents, but, if correct, it has a similar structure to the territory, which accounts for its usefulness…” A. Korzybski, Science & Sanity, 4th Ed. 1958, pp. 58-60 (quoted from: R Bandler & J Grinder, Patterns of the hypnotic Techniques of Milton H. Erickson, M.D. Vol 1, 1975, pp 181) Human beings model the world. We learn by constructing models and then subjecting those models to tests in order to determine their validity.