Deltas were causing canvas centering

test/test_viewport_module.js

 /*
 This file is part of the Juju GUI, which lets users view and manage Juju
 environments within a graphical interface (https://launchpad.net/juju-gui).
 Copyright (C) 2012-2013 Canonical Ltd.
 
 This program is free software: you can redistribute it and/or modify it under
 the terms of the GNU Affero General Public License version 3, as published by
 the Free Software Foundation.
 
 This program is distributed in the hope that it will be useful, but WITHOUT
@@ skipping 93 matching lines @@
           done();
         });
   });
 
   beforeEach(function() {
     height = Math.floor(Math.random() * 1000);
     width = Math.floor(Math.random() * 1000);
     // Build test doubles that record height and width settings.
     topo = {
       get: function() {
+        // Default to adding 1 to each width and height so that the size
+        // returned is always different than the size as viewed by the
+        // setAllTheDimensions method; this will cause the viewport to be
+        // centered.
         return [width + 1, height + 1];

[benji, 2013/09/05 17:08:49]

A comment as to why the "+ 1"s are needed would be nice.

       },
       vis: {},
       fire: function(evt) {
         eventFired = evt;
       }
     };
     topo.set = testUtils.setter(topo);
     topo.vis.attr = testUtils.setter(topo.vis);
     view = new views.ViewportModule();
     canvas = {style: {}};
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     assert.equal(topo.vis.width, width);
     assert.equal(topo.vis.height, height);
   });
 
   it('should center canvas', function() {
     assert.equal(eventFired, 'panToCenter');
   });
 
   it('should not center canvas if no changes', function() {
     topo.get = function() {
+      // Return just the width and height so that the viewport appears not to
+      // have been resized, ensuring that the panToCenter event is not fired.
       return [width, height];
     };
     eventFired = false;
     view.setAllTheDimensions(dimentions, canvas, svg, topo, zoomPlane);
     assert.equal(eventFired, false);
   });
 });