New test helpers to acquire and release charts

Since we changed the way how meta data are stores, now unit tests need to work on real Chart instances. This commit brings some helpers to inject/cleanup HTML canvas and it's wrapper into/from the DOM.

diff --git a/test/mockContext.js b/test/mockContext.js
index 38755362cfe0f48ad5f6beccfed3f198744c1f83..17d9ad5d8fbe91c4c6145e73d1e30a72741fc9a7 100644 (file)
--- a/test/mockContext.js
+++ b/test/mockContext.js
@@ -57,7 +57,7 @@
                        },
                });
        };
-       
+
        Context.prototype._initMethods = function() {
                // define methods to test here
                // no way to introspect so we have to do some extra work :(
@@ -121,4 +121,75 @@
        window.createMockContext = function() {
                return new Context();
        };
-})();
\ No newline at end of file
+
+       // Canvas injection helpers
+       var charts = {};
+
+       function acquireChart(config, style) {
+               var wrapper = document.createElement("div");
+               var canvas = document.createElement("canvas");
+               wrapper.className = 'chartjs-wrapper';
+
+               style = style || { height: '512px', width: '512px' };
+               for (var k in style) {
+                       wrapper.style[k] = style[k];
+                       canvas.style[k] = style[k];
+               }
+
+               canvas.height = canvas.style.height && parseInt(canvas.style.height);
+               canvas.width = canvas.style.width && parseInt(canvas.style.width);
+
+               // by default, remove chart animation and auto resize
+               var options = config.options = config.options || {};
+               options.animation = options.animation === undefined? false : options.animation;
+               options.responsive = options.responsive === undefined? false : options.responsive;
+               options.defaultFontFamily = options.defaultFontFamily || 'Arial';
+
+               wrapper.appendChild(canvas);
+               window.document.body.appendChild(wrapper);
+               var chart = new Chart(canvas.getContext("2d"), config);
+               charts[chart.id] = chart;
+               return chart;
+       }
+
+       function releaseChart(chart) {
+               chart.chart.canvas.parentNode.remove();
+               delete charts[chart.id];
+               delete chart;
+       }
+
+       function releaseAllCharts(scope) {
+               for (var id in charts) {
+                       var chart = charts[id];
+                       releaseChart(chart);
+               }
+       }
+
+       function injectCSS(css) {
+               // http://stackoverflow.com/q/3922139
+               var head = document.getElementsByTagName('head')[0];
+               var style = document.createElement('style');
+               style.setAttribute('type', 'text/css');
+               if (style.styleSheet) {   // IE
+                       style.styleSheet.cssText = css;
+               } else {
+                       style.appendChild(document.createTextNode(css));
+               }
+               head.appendChild(style);
+       }
+
+       window.acquireChart = acquireChart;
+       window.releaseChart = releaseChart;
+       window.releaseAllCharts = releaseAllCharts;
+
+       // some style initialization to limit differences between browsers across different plateforms.
+       injectCSS(
+               '.chartjs-wrapper, .chartjs-wrapper canvas {' +
+                       'border: 0;' +
+                       'margin: 0;' +
+                       'padding: 0;' +
+               '}' +
+               '.chartjs-wrapper {' +
+                       'position: absolute' +
+               '}');
+})();