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Showing posts from March, 2012

A simple test of time.

Last week I was performing another of my 5 minute testing exercises. As posted before, if I get a spare few minutes I pick something and investigate. This time, I'd picked Google Calendar. One thing people use calendars for is logging what they have done. That is, they function as both schedulers and record keepers. You add what you planned to do, and they also serve as a record of what you did - useful for invoicing clients or just reviewing how you used your time. Calendars and software based on them are inherently difficult to program and as such are often a rich source of bugs. People make a lot of assumptions about time and dates. For example that something ends after it starts. That may sound like something that 'just is true', but there are a number of reasons why that might not be the case. Some examples are: You type in the dates the wrong way round (or mix up your ISO and US dates etc) You're working with times around a DST switch, when 30min after 0

How to avoid testing in circles.

I once had an interesting conversation with a colleague who worked in a company selling hotel room bookings. The problem was interesting. Their profits depended on many factors. Firstly, fluctuating demand e.g.: Holidays, Weekends, Local events etc. Secondly, varying types of demand e.g. Business customers, Tourists, Single night bookings or e.g.: 11 day holidays. They also had multiple types of contracts on the rooms. For some, they might have had the exclusive right to sell [as they had pre-paid], for others they had an option to sell [at a lower profit] etc. My naive view had been they priced the room bookings at a suitable mark up, upping that markup for known busy times etc. For example a tourist hotel hotel near the Olympics would be a high mark up, the tourist hotel room in winter would have incurred less of a markup. Better to get some money than none at all). He smiled and said some places do that, but he didn't. He had realised his team had a bias towards making a hea

Manual means using your hands (and your head)

I recently purchased a Samsung Galaxy Tab and an iPad2. Unlike many of my previous gadget purchases, these new gadgets have become very much part of the way I now work and play. One thing I like about them, is their tactile nature. You have a real sense that their is less barrier between you and what you want to do. If you want to do something - you touch it - and it 'just' does it. I don't have to look at a different device, click a couple of keys or move a box on a string  to get access to what I can see right in front of me. Features such as the haptic feedback provide a greater feeling that you are actually working with a tool, rather than herding unresponsive 'icons' or typing magic incantations into a typing device, originally conceived 300 years ago . The underlying software systems used in these devices is a UNIX variant, just like the computer systems that underpin the majority of real world systems from the internet to a developer's shiny Apple Ma