Fix initial creation of subordinates.

Fix initial creation of subordinates.

When creating a subordinate service initially, it was not being laid out properly by the pack layout, nor was it seeming to have drag events attached.  Pack layout was expecting a value accessor function to return some number greater than zero when constructing its radius, which informs the x/y coordinates.  Returning zero results in NaN for all three values, thus positioning the service at (0,0) and causing drag events to fail when updating the service's coordinates with dx/dy + NaN.  This branch fixes this by ensuring that zero is never returned as the node's value.  This fix is quick and intended to make the UI function with the current layout algorithm.  Future layout algorithms, if they're designed by hand, will need to keep this in mind as well.

https://code.launchpad.net/~makyo/juju-gui/adding-subordinates/+merge/135022

(do not edit description out of merge proposal)

[matthew.scott, 2012-11-20 00:13:38]

Please take a look.

[benjamin.saller, 2012-11-20 13:31:33]

The diff looks fine, but there is behavior we expect on subordinates that isn't
be tested, I think we can at minimum check to see if subs get x/y position
assignment? What do you think?

[bac, 2012-11-20 14:50:48]

Looks good Matt.  Thanks.

https://codereview.appspot.com/6856067/diff/1/app/views/environment.js
File app/views/environment.js (right):

https://codereview.appspot.com/6856067/diff/1/app/views/environment.js#newcod...
app/views/environment.js:323: })
maybe this would be more readable:

min(1, d.unit_count)

[matthew.scott, 2012-11-20 15:59:08]

A test was added as well, but rather than just testing whether or not
subordinates had been placed properly, it tests that all services have been
placed properly.

https://codereview.appspot.com/6856067/diff/1/app/views/environment.js
File app/views/environment.js (right):

https://codereview.appspot.com/6856067/diff/1/app/views/environment.js#newcod...
app/views/environment.js:323: })
On 2012/11/20 14:50:48, bac wrote:
> maybe this would be more readable:
> 
> min(1, d.unit_count) 

Thanks! Did Math.max(d.unit_count, 1); (since we want 1 or higher)

[matthew.scott, 2012-11-20 16:26:44]

Please take a look.

[bac, 2012-11-21 17:27:11]

The new test makes sense to me Matt.

[matthew.scott, 2012-11-21 17:35:56]

*** Submitted:

Fix initial creation of subordinates.

When creating a subordinate service initially, it was not being laid out
properly by the pack layout, nor was it seeming to have drag events attached. 
Pack layout was expecting a value accessor function to return some number
greater than zero when constructing its radius, which informs the x/y
coordinates.  Returning zero results in NaN for all three values, thus
positioning the service at (0,0) and causing drag events to fail when updating
the service's coordinates with dx/dy + NaN.  This branch fixes this by ensuring
that zero is never returned as the node's value.  This fix is quick and intended
to make the UI function with the current layout algorithm.  Future layout
algorithms, if they're designed by hand, will need to keep this in mind as well.

R=benjamin.saller, bac
CC=
https://codereview.appspot.com/6856067