[Seaside] ShoreComponents test cases -- worth doing?

[David Shaffer]

Pavel Krivanek wrote:

> It’s really mainly "self check“. Every component except real root
> should have a parent. If we will use #mustBeChild method, we loose
> this checking functionality anyway. What about to use any nonviolent
> way to warn the programmer (any message in Transcript etc.)?


Hmm...then there would be lots of Transcript traffic for my test cases. 
Better than the current situation but not ideal.  Also means the
self-check isn't as in-your-face as you might want it to be (no debugger
means it's too easily ignored and eventually will just become an
annoyance).  Is it feasible to throw an exception in #parent?

parent
    "Returns the receivers parent component"

    ^parent ifNil: [self class canBeRoot ifFalse: [self error:
'Component has no parent.  Consider creating the instance with parent:
instead of new.'] ifTrue: []]

This delays the error message a bit but in cases where it _should_ occur
it seems like it would.  That is, sending #parent to a component asserts
that it either has a parent or is allowed to be a root component,
otherwise its an error.  So, non-canBeRoot components who are parentless
are OK until you ask them for their parent.  It's a bit of a change in
philosophy.  I made this change in my image and the demos still run just
fine.  This would fix my tests since most of these components don't
really need to be parented (they never send #parent to themselves).

Another idea:  What if the component checks to see if its class it is
the root class of the application?

new
    "Returns a new instance of the receiver"

    (self canBeRoot or: [self classIsRootOfApplication])
        ifTrue: [ ^ super new ]
        ifFalse: [ self error: 'use parent:'.].

classIsRootOfApplication
    ^(self session application preferenceAt: #rootClass) = self

So, if the component was intentionally made the root of an application
it is OK.  Otherwise it is an error.  This would catch all of the cases
you were talking about.  It seems a bit hack-ish though.
 

David