get raw file size

test/arguments-test.js

@@ -1,3 +1,5 @@
+var fs = require('fs');
+var path = require('path');
 var assert = require('assert');
 var StyleStats = require('../lib/stylestats.js');
 
@@ -110,11 +112,19 @@ describe('Constructor Test', function () {
   describe('File path', function() {
     it('should return file size', function(done) {
       var dirStats = new StyleStats('test/fixture/');
+      var size = fs.readdirSync('test/fixture/').filter(function (file) {
+        return path.extname(file) === '.css'
+      }).map(function (file) {
+        return fs.readFileSync('test/fixture/' + file).length;
+      }).reduce(function (previous, current, index, array) {
+        return previous + current;
+      });
+
       dirStats.parse(function(error, dirResult) {
         if (error) {
           throw error;
         }
-        assert.equal(dirResult.size, 20462);
+        assert.equal(dirResult.size, size);
         done();
       });
     });