Hi All,

I've used TDD for some time now but rather in an inside-out fashion, i.e.
instead
of thinking about user stories encompassing the whole application first, I used
TDD to drive small parts. For example I knew "I need that component A now" and
then wrote tests for it before implementing it.

Now I'd like to start with an outside-in design (i.e. story-based) since my
previous approaches
proved to be unsatisfying in the long run. But I find it really hard to come up
with the first
test to get things rolling.

The situation is as follows:
I'd like to write an application for a mobile device (with Java ME for all of
you who have
worked with it yet) that renders a certain animation. That is, it should just
have a canvas
and keep drawing the animation forever.
As a general design decision, I want to use the Presenter-First technique
(http://www.atomicobject.com/pages/Presenter+First) for the whole application.

So I spent some thoughts on this and I finally came up with the idea that I
should
have a test like "When the next frame is drawn, the view uses the current
coordinates
stored in the model to draw the outline of the animation". In
presenter-first-speech this
would result in a model storing coordinates for my animation, a view
representing the
canvas and a presenter connecting both the view and the model. Thus, the test
would
be written for the presenter.

But then I realized that this is already "inside" of the application and not the
outside.
An outside test would probably be something like "When the application starts,
the canvas
is shown empty". Yet I don't really have a clear picture in my mind of how the
whole thing
should evolve from there.

I still find it very difficult to think in "application-wide stories" rather
than in
"component- or class-wide stories". It's much easier to think of how a specific
class fits into an
existing picture than defining the frame for the whole application with a single
test.
What do you think how I should start driving this application? What should I use
as the first test and how
should I go on? For me, the first test in outside-in design to get started is
really the hardest
part about TDD. Perhaps some of you have experienced similar problems?

regards
Andreas Krügersen

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