Use istanbul for test coverage

If there is no coverage at all we get
an empty global variable and the lcov
empty file may cause coveralls failure.

Use mkdirp() to create lib-cov

.gitignore

@@ -5,3 +5,7 @@ build
 lib-cov
 node_modules
 vendor
+test/html-report
+test/lcov-report
+test/lcov.info
+coverage

package.json

@@ -64,7 +64,7 @@
   "devDependencies": {
     "coveralls": "^2.11.2",
     "cross-spawn": "^1.0.3",
-    "jscoverage": "^0.5.9",
+    "istanbul": "^0.3.13",
     "jshint": "^2.8.0",
     "mocha": "^2.2.5",
     "mocha-lcov-reporter": "^0.0.2",

scripts/coverage.js

@@ -2,62 +2,80 @@
  * node-sass: scripts/coverage.js
  */
 
-require('../lib/extensions');
+var Mocha = require('mocha'),
+    fs = require('fs'),
+    path = require('path'),
+    mkdirp = require('mkdirp'),
+    coveralls = require('coveralls'),
+    Instrumenter = require('istanbul').Instrumenter,
+    Report = require('istanbul').Report,
+    Collector = new require('istanbul').Collector,
+    sourcefiles = ['index.js', 'extensions.js', 'render.js'],
+    summary= Report.create('text-summary'),
+    lcov = Report.create('lcovonly', { dir: path.join('coverage') }),
+    html = Report.create('html', { dir: path.join('coverage', 'html') });
 
-var bin = require('path').join.bind(null, __dirname, '..', 'node_modules', '.bin'),
-    spawn = require('child_process').spawn;
-
-/**
- * Run test suite
- *
- * @api private
- */
-
-function suite() {
+function coverage() {
+    var mocha = new Mocha();
+    var rep = function(runner) {
+      runner.on('end', function(){
+        var cov = global.__coverage__,
+            collector = new Collector();
+        if (cov) {
+          mkdirp(path.join('coverage', 'html'), function(err) {
+			if (err) { throw err; }
+			collector.add(cov);
+			summary.writeReport(collector);
+			html.writeReport(collector);
+			lcov.on('done', function() {
+			  fs.readFile(path.join('coverage', 'lcov.info'), function(err, data) {
+				 if (err) { console.error(err); }
+				 coveralls.handleInput(data.toString(),
+				   function (err) { if (err) { console.error(err); } });
+			  });
+			});
+			lcov.writeReport(collector);
+          });
+        } else {
+          console.warn('No coverage');
+        }
+      });
+    };
+    var instrumenter = new Instrumenter();
+    var instrumentedfiles = [];
+    var processfile = function(source) {
+		 fs.readFile(path.join('lib', source), function(err, data) {
+           if (err) { throw err; }
+           mkdirp('lib-cov', function(err) {
+             if (err) { throw err; }
+			 fs.writeFile(path.join('lib-cov', source),
+			   instrumenter.instrumentSync(data.toString(),
+                 path.join('lib', source)),
+               function(err) {
+                 if (err) { throw err; }
+                 instrumentedfiles.push(source);
+                 if (instrumentedfiles.length === sourcefiles.length) {
+                   fs.readdirSync('test').filter(function(file){
+                     return file.substr(-6) === 'api.js';
+                   }).forEach(function(file){
+                     mocha.addFile(
+                       path.join('test', file)
+                     );
+                   });
                    process.env.NODESASS_COV = 1;
-
-  var coveralls = spawn(bin('coveralls'));
-
-  var args = [bin('_mocha')].concat(['--reporter', 'mocha-lcov-reporter']);
-  var mocha = spawn(process.sass.runtime.execPath, args, {
-    env: process.env
+                   mocha.reporter(rep).run(function(failures) {
+                     process.on('exit', function () {
+                       process.exit(failures);
                      });
-
-  mocha.on('error', function(err) {
-    console.error(err);
-    process.exit(1);
                    });
-
-  mocha.stderr.setEncoding('utf8');
-  mocha.stderr.on('data', function(err) {
-    console.error(err);
-    process.exit(1);
+                 }
 			   });
-
-  mocha.stdout.pipe(coveralls.stdin);
-}
-
-/**
- * Generate coverage files
- *
- * @api private
- */
-
-function coverage() {
-  var jscoverage = spawn(bin('jscoverage'), ['lib', 'lib-cov']);
-
-  jscoverage.on('error', function(err) {
-    console.error(err);
-    process.exit(1);
            });
-
-  jscoverage.stderr.setEncoding('utf8');
-  jscoverage.stderr.on('data', function(err) {
-    console.error(err);
-    process.exit(1);
 		 });
-
-  jscoverage.on('close', suite);
+       };
+    for (var i in sourcefiles) {
+      processfile(sourcefiles[i]);
+    }
 }
 
 /**