[TFUI] RE: [TDD] Re: A better way to test the GUI?

Hi Phlip,

> -----Original Message-----
> From: Phlip [mailto:[email protected]] 
> Sent: Monday, January 31, 2005 11:00 AM
> To: [email protected]; 
> [email protected]
> Subject: Re: [TDD] Re: A better way to test the GUI?
> 
> 
> 
> Charlie Poole wrote:
> 
> > Hi Phlip,
> > 
> > In theory, it's simple, but in practice?
> > 
> > I don't know about Java, but in .NET the Graphics class is sealed 
> > doesn't implement any interface but IDisposable. So it's 
> not easy to 
> > substitute a mock. However, the class is 
> MarshalByReference, so with 
> > some work, you should be able to spin up a proxy that would 
> convince 
> > Paint it was talking to a real System.Drawing.Graphics object.
> > 
> > The graphics object is passed to OnPaint as a member of a 
> > PaintEventArgs, which is trivial to construct. You would 
> just need the 
> > pseudo-Graphics object we just hypothesized and a bounding 
> rectangle.
> > 
> > Of course, OnPaint is called by the .NET framework, 
> whenever painting 
> > is needed. It's not likely that we can get .NET to use our 
> own mock in 
> > making this call, so we need to Mock .NET as well. :-;
> > 
> > For the simple cases, you could derive a class from your custom 
> > control, expose a public method that called OnPaint, and 
> pass in your 
> > own object. Alternatively, you could call it through 
> reflection. For 
> > the non-simple cases, well... it's not that "simple".
> > 
> > I'm not disagreeing with your principle, but I think you may have 
> > given the impression that it's _easy_ to plug in a mock graphics 
> > object, and it currently isn't. I'm doing a lot of work on 
> this and I 
> > might eventually have a framework that does this stuff. If 
> we can make 
> > it as easy as using a mock framework, then the
> > economic tradeoff changes. Right now, you have to be 
> willing to put in a
> > fair bit of effort, which makes the
> > approach viable only for projects that see a very strong 
> need for this
> > level of testing.
> 
> Is my estimate correct that there is no widespread, commonly 
> available canvas control available for the Java GUIs and C# GUIs?
>
> This is not rocket surgery. If you don't need super-advanced 
> real-time visualizations, then you don't need raw paint 
> commands. The effort to mock those commands exceeds the 
> effort to build a simple canvas control, like Tk Canvas.

I'm not entirely sure what you mean by a canvas control. I was
responding
to the notion that it's relatively simple to mock the Graphics object.
Maybe
that's not what you meant though...

Charlie

> 
> -- 
> Phlip
> 
> 
>  
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
> 
> 




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