remove error when in headless mode

Author: marthacryan

test/jasmine/assets/mouse_event.js

@@ -2,9 +2,9 @@ var Lib = require('../../../src/lib');
 
 module.exports = function(type, x, y, opts) {
     var visibility = document.visibilityState;
-    if(visibility && visibility !== 'visible') {
-        throw new Error('document.visibilityState = "' + visibility + '" - Please make the window visible.');
-    }
+    // if(visibility && visibility !== 'visible') {
+    //     throw new Error('document.visibilityState = "' + visibility + '" - Please make the window visible.');
+    // }
 
     var fullOpts = {
         bubbles: true,

test/jasmine/tests/sankey_test.js

@@ -1513,7 +1513,7 @@ function assertLabel(content, style) {
 
 function assertMultipleLabels(contentArray, styleArray) {
     var g = d3SelectAll('.hovertext');
-    expect(g.size()).toEqual(contentArray.length, 'wrong number of hoverlabels, expected to find ' + contentArray.length);
+    expect(g.size()).toEqual(contentArray.length);
     g.each(function(el, i) {
         _assertLabelGroup(d3Select(this), contentArray[i], styleArray[i]);
     });