[Help] What is the best way to compare two forms 
for a sunit test?  

Hi Andreas,

Thanks for your help. Very informatiive.

I think it turned out a little more than I needed for
the purpose I had in mind. My problem was how to store
something to compare with the graphic forms generated
on the fly. Since the test had control of the size and
depth of the generated form, I settled for storing the
hashes of the bits for each form generated. If they
match nothing has changed and the test is green. If
they don't then the examples need to be visually
inspected which will point to whether the problem is
with the testee or the test. If the testee passes the
original visual test then the test can be fixed by
simply creating new hashes.  And of course looking
into what changed to cause the testing to fail.

I am not sure how the bit hashes will fare across
platforms but that will have to be faced when it
happens. Generating platform specific hashes is always
a possibility.

Thanks again for your reply. I'm sure I will find a
good use for the information. 

Yours in curiosity and service, -- Jerome Peace



***

>  
>  Andreas Raab andreas.raab at gmx.de 
>  Mon Mar 5 07:46:48 UTC 2007 replied:
>  
>  
>  Combination rule 32 (RGB diff) which counts the
number
>  of differing 
>  pixels in two forms is your friend. For example:
>  
>     (BitBlt toForm: Display)
>  	sourceForm: Display;
>  	combinationRule: 32;
>  	copyBits.
>  
>  will answer zero (no difference, since it's the
same
>  form). One caveat 
>  though: This only works for >=16bpp; if you need
less
>  than you may have 
>  to look at rule 22 which is a bit tricky since it
does
>  not clip properly 
>  (but it may still be good enough for your
purposes).
>  
>  Cheers,
>     - Andreas
>  
>  Jerome Peace wrote:
>  > I have some code for which I have created
graphical
>  > tests .
>  > 
>  > These tests will produce a picture that looks
right
>  > when the code is working.
>  > 
>  > Now I want to (as lazily as possible) create unit
>  > tests to prove the code and get it past the
release
>  > team watch dogs.
>  > 


 
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