Test code refactor #63

Use mocha for feature-specific unit tests

Add test coverage report via istanbul

test/bench/parallel.js

@@ -0,0 +1,41 @@
+'use strict';
+
+var assert = require('assert');
+var async = require('async');
+
+var sharp = require('../../index');
+var fixtures = require('../fixtures');
+
+var width = 720;
+var height = 480;
+
+sharp.concurrency(1);
+
+var timer = setInterval(function() {
+  console.dir(sharp.counters());
+}, 100);
+
+async.mapSeries([1, 1, 2, 4, 8, 16, 32, 64, 128], function(parallelism, next) {
+  var start = new Date().getTime();
+  async.times(parallelism,
+    function(id, callback) {
+      /*jslint unused: false */
+      sharp(fixtures.inputJpg).resize(width, height).toBuffer(function(err, buffer) {
+        buffer = null;
+        callback(err, new Date().getTime() - start);
+      });
+    },
+    function(err, ids) {
+      assert(!err);
+      assert(ids.length === parallelism);
+      var mean = ids.reduce(function(a, b) {
+        return a + b;
+      }) / ids.length;
+      console.log(parallelism + ' parallel calls: fastest=' + ids[0] + 'ms slowest=' + ids[ids.length - 1] + 'ms mean=' + mean + 'ms');
+      next();
+    }
+  );
+}, function() {
+  clearInterval(timer);
+  console.dir(sharp.counters());
+});