How to test a JavaScript SVG/Canvas application?
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We are evaluating future work on a graphical JavaScript application that uses HTML5-Technologies like SVG and Canvas. One big problem (as with all UI centered applications) is how to write tests for all the functionality. It would not be sufficient if we could only test the JavaScript logic, but we also need to know, if the interface is working.

So we would at least need something like Selenium that enables us to interact with SVG/Canvas. Also, of course, there must be some kind of framework to write ordinary unit tests for the logic behind the drawing. And it should be free to use.

Is there something like that available? Also, since we have no previous experience in testing of this kind of software at all, we would appreciate any kind of tips how to solve our problem and how this is done usually. I trust, we are not the first ones thinking about that.

Thanks in advance!