fix #620, infer the input files from sources

karma.conf.js

 // Karma configuration
 // Generated on Mon Apr 20 2015 06:33:20 GMT-0700 (PDT)
 
 module.exports = function(config) {
   var configuration = {
 
     // base path that will be used to resolve all patterns (eg. files, exclude)
     basePath: '',
 
     // frameworks to use
     // available frameworks: https://npmjs.org/browse/keyword/karma-adapter
     frameworks: ['mocha', 'requirejs', 'chai'],
 
     // list of files / patterns to load in the browser
     files: [
       'lib/runtime/dart_*.js',
       // {pattern: 'test/browser/*.js', included: false}
-      'gen/codegen_output/async_helper/async_helper.js',
-      'gen/codegen_output/expect/expect.js',
-      'gen/codegen_output/path/path.js',
-      'gen/codegen_output/stack_trace/stack_trace.js',
-      'gen/codegen_output/js/js.js',
-      'gen/codegen_output/matcher/matcher.js',
-      'gen/codegen_output/unittest/unittest.js',
+      'gen/codegen_output/pkg/*.js',
       'gen/codegen_output/language/**.js',
       'gen/codegen_output/language/**.err',
       'gen/codegen_output/corelib/**.js',
       'gen/codegen_output/corelib/**.err',
       'gen/codegen_output/lib/convert/**.js',
       'gen/codegen_output/lib/html/**.js',
       'gen/codegen_output/lib/math/**.js',
       'gen/codegen_output/lib/typed_data/**.js',
       'gen/codegen_output/lib/*/**.err',
       'test/browser/*.js',
@@ skipping 63 matching lines @@
     configuration.browsers = ['chrome_canary_travis'];
     configuration.autoWatch = false;
     // Enable this for more logging on Travis.  It is too much for Travis to
     // automatically display, but still results in a downloadable raw log.
     // configuration.logLevel = config.LOG_DEBUG;
     configuration.client.captureConsole = true;
   }
 
   config.set(configuration);
 };