comment and fix on assertPlotSize with margin.pad

Author: alexcjohnson

test/jasmine/assets/custom_assertions.js

@@ -220,6 +220,10 @@ exports.assertElemInside = function(elem, container, msg) {
 /*
  * quick plot area dimension check: test width and/or height of the inner
  * plot area (single subplot) to verify that the margins are as expected
+ *
+ * Note: if you use margin.pad on the plot, width and height will be larger
+ * than you expected by twice that padding.
+ *
  * opts can have keys (all optional):
  *   width (exact width match)
  *   height (exact height match)

test/jasmine/tests/legend_test.js

@@ -527,7 +527,7 @@ describe('legend relayout update', function() {
     it('should hide and show the legend', function(done) {
         var mockCopy = Lib.extendDeep({}, mock, {layout: {
             legend: {x: 1.1, xanchor: 'left'},
-            margin: {l: 50, r: 50},
+            margin: {l: 50, r: 50, pad: 0},
             width: 500
         }});