Layout testing

gistfile1.js

  var runTests = function(callback) {
    var testsFinishedCount = 0;
    var testFailures = [];
    var layouts = config.SETTINGS.layouts;

    var processNextLayout = function() {
      var layout = layouts.shift();
      if (layout) {
        var rasterizeCmd = RASTERIZE_CMD_TEMPLATE({
          url: buildUrl(layout.url),
          path: config.SETTINGS.tmpPath + layout.page + '.png'
        }); 

        exec(rasterizeCmd, function(output) {
          var diffCmd = DIFF_CMD_TEMPLATE({
            file1: config.SETTINGS.baselinePath + layout.page + '.png',
            file2: config.SETTINGS.tmpPath + layout.page + '.png',
          });

          exec(diffCmd, function(error, stdout, stderr) {
            var result = parseDiff(stdout);
            var failed = result && result.diffAmount > config.SETTINGS.tolerancePercent;
            if (failed) {
              testFailures.push({
                page: layout.page,
                diffAmount: result.diffAmount
              });
            }

            testsFinishedCount++;
            processNextLayout();
          });
        });
      } else {
        callback(testsFinishedCount, testFailures);
      }
    };

    processNextLayout();
  };