Re: Tiling features in Mutter

[Oliver Mangold <o mangold googlemail com>]

On 17.03.2011 16:23, Jeffery Olson wrote:
> Encapsulation, low coupling and seperation-of-concerns. These are all
> valuable patterns that we can leverage here.
Okay, you have a point here. This is certainly the best one can do under 
dynamic typing.

I'm not sure if it is relevant for the specific project, but still I can 
think of situations where it is not possible to run the API-using code 
directly, e.g. if a hook to a signal that will only be raised on user 
action, the interface of the hook call cannot be tested.

> Now, this doesn't negate the need to test a set of bindings to the
> mutter/gnome-shell C codebase for API churn. What we need is a way to
> get access to a Looking Glass-like REPL from the CLI, that would maybe
> fire up a new process with a "sandboxed" gnome-shell session that
> wasn't actually bound to an xdisplay, but that we could use to verify
> bindings, etc. This, once again, falls into the "not yet done"
> category. I don't know the feasibility of such an endevour. There's a
> possibility to eval javascript code in the current gnome-shell session
> via dbus, but I haven't explored this much either (and don't know how
> useful itd really be).
Of course much can be done in principle, but it still will be a lot of 
work for the writer of unit tests. Even if you have this, you still have 
to bring this sandbox environment into a state, where it is possible to 
call the function you want to test, e.g. if you call 
workspace.get_windows() you probably should have some windows open, and 
if your function only messes with windows that fulfill a certain 
condition (tiled, maximized, specific title, ...) you first have to 
bring a window in the specific state, etc.

I must admit, though, that static typing is not a cure to detect all API 
incompatibilities, e.g. if the behaviour of a method changes but not the 
interface, still it is something I like very much, as for real world 
purposes it finds quite a lot problems simply by compiling.