Implementation and Testing.

As with the low-level design activity discussed last week, in content-focused multimedia applications there is no sharp dividing line between low-level design (layout, editing content slightly, polishing the look and feel of the application), implementation and testing. Components are built and tested in a continual cycle. However, it is important to go round this cycle with care, and the following points may be of use:

• At each stage of implementation, have a goal in mind, e.g. 'insert images into component, get them the right size, compression and layout', 'overlay sounds, get quality and timing right' and work towards achieving this goal. Implement and test with this goal in mind.
• Don't 'thrash about' with your implementation and testing, work in fairly substantial chunks - once you have decided how to do something, have the confidence to construct your component without checking every tiny change and addition.
• Test the components you have constructed in their target environment: put them in the final file structure (and check out links), test them on each target platform, check out performance with the final delivery technology.
• Keep a careful track of 'signed off' components, and don't modify them any further without good reason and comprehensive further testing. Have a 'final product' file area and don't mess about with it.

Testing is divided into two major stages: unit testing and integration testing. The aims of each are different. Unit testing is ensuring that a low-level component works as it should in isolation. Integration testing is ensuring that low-level components work when brought together. This basic picture, from software engineering, is made more complicated in content-focused multimedia, since nearly all multimedia implementation involves integrating components of content. Despite this, keep these two activities in mind, and try and decide whether you are testing that a simple element looks, sounds, performs, etc. as it should; or whether you are testing that elements fit together.

You aren't really going to be doing any formal testing of your assignment prototype. Just make sure that it hangs together and can actually work as a demonstration of principle.