Testing, Fixing and Costs

For those of you who don’t know me, you almost certainly won’t know what I do. Of course, there are probably a load of people who do know me, who still don’t know what I do (and, no, “Nothing” is not the answer). I work as a software tester and I have done for the last 7+ years now in a few different places.

cost_curve1Generally, this job involves a fair bit of evangalism – sometimes it’s quite successful (eg Promoting the use of Bugzilla as a defect tracking tool). One of my favourite diagrams is that shown in this post – I like this graph a lot. It is a graph showing the rough relationship between the cost of fixing a bug or defect, and what stage of the development process that bug or defect was found.

It’s fairly clear from the graph that, the later you realise there is a problem, the more it costs you to go back and unravel what is wrong and sort it. The reasons are fairly clear – if you find a problem at a later stage, you often have to go right back to the beginning of the process of development, testing and so on.

Some notes I like to make relating to this:

  1. Even if you are already employed by a company, you are not “free”. Having someone fix a problem, and work repeated costs money – “we already pay their wages” is not an argument! Sheffield Teaching Hospitals Trust – take heed (Quote from the Reg article: The trust argued that the consequences of its decision making had not cost public money, “just time and effort by the IT teams”.).
  2. Accurate. timely requirements are essential. Finding out that you have mis-specified something as it is nearing the release date is a Bad Thing™.
  3. Not having requirements before coding is asking for even more trouble.
  4. Changing requirements part way through the process (or, worse, finding out during testing that your requirements were duff!) is much along the lines of 2 and 3 with similar outcomes (moving goalposts anyone?).
  5. Doing unit testing is much better than sending code straight to the testers – it saves a lot of heartache on both sides…
  6. Actually having enough time to perform a sufficient level of testing can save you an enormous amount of hassle and cost.
  7. Squishing bugs as you go at the earliest possible opportunity is much advised – multiple bugs can quickly make a system unusable and costly to fix up. (There is another similarly shaped graph – see it as The Law Of Bugterial Infection)
  8. No one is perfect… not even me 😉

Feel free to use the graph above if you want and evangelise away…

Circumzenithal Arc

Circumzenithal Arc - Abingdon, 15th Aug 2008

Saw this circumzenithal arc on Friday 15th from Abingdon. Looks much like an upside down rainbow above the sun (which needs to be lower than 33 degrees or so for this to occur) – it occurs due to horizontally orientated ice crystals high in the upper atmosphere.

Only had the camera on my phone so the image is a bit ropey, but hopefully clear enough…

M42, M43, NGC 1977 – The Orion Nebula and Running Man

RA: 05h 35m 17s, Dec: -5°23’28” m42-200702061024.jpg
The Orion Nebula (M42 (NGC 1976) & M43) is located in the “sword” of Orion and is a large emission nebula that is easily visible to the naked eye. It is an area of star formation – the closest such to Earth at a distance of 1500 light years. The nebula is an estimated 30 light years across, and contains a young star cluster (the Trapezium) in the bright core of the nebula. The reflection nebula at the top of the image is the “Running Man” nebula (NGC 1973, 1975 and 1977) – so named due to the resemblance of the silhouetted dust lanes.

I had lots of trouble with this image (taken on 6th Feb, 2007) – the flats I took didn’t work out (there’s the odd artifact here and there!), and I’m not quite happy with the colour balance – have another go at this later I think…

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