chore(build): refactor test.unit.cjs to use the broccoli pipeline

This change solves several problems:
- the broccoli pipeline is used to compile the node/cjs tree upon any change to the modules/ directory
- jasmine tests run in a new process removing the need to clean up environment after each test
- since we transpile only those test files that are actually needed for node/cjs build, we transpile less and don't need to filter out tests

gulpfile.js

@@ -1,5 +1,6 @@
 var autoprefixer = require('gulp-autoprefixer');
 var format = require('gulp-clang-format');
+var fork = require('child_process').fork;
 var gulp = require('gulp');
 var gulpPlugins = require('gulp-load-plugins')();
 var sass = require('gulp-sass');
@@ -8,6 +9,7 @@ var runSequence = require('run-sequence');
 var madge = require('madge');
 var merge = require('merge');
 var path = require('path');
+var Q = require('q');
 
 var gulpTraceur = require('./tools/transpiler/gulp-traceur');
 var clean = require('./tools/build/clean');
@@ -465,27 +467,38 @@ gulp.task('test.unit.cjs/ci', function () {
 gulp.task('test.unit.cjs', ['build.js.cjs'], function () {
   //Run tests once
   runSequence('test.unit.cjs/ci', function() {});
+});
 
-  //Watcher to transpile file changed
-  gulp.watch(CONFIG.transpile.src.js.concat(['modules/**/*.cjs']), function(event) {
-    var relPath = path.relative(__dirname, event.path).replace(/\\/g, "/");
-    gulp.src(relPath)
-      .pipe(gulpPlugins.rename({extname: '.'+ 'js'}))
-      .pipe(gulpTraceur(CONFIG.transpile.options.js.cjs, file2moduleName))
-      .pipe(transformCJSTests())
-      .pipe(gulp.dest(CONFIG.dest.js.cjs + path.dirname(relPath.replace("modules", ""))));
-  });
-  //Watcher to run tests when dist/js/cjs/angular2 is updated by the first watcher (after clearing the node cache)
-  gulp.watch(CONFIG.dest.js.cjs + '/angular2/**/*.js', function(event) {
-    for (var id in require.cache) {
-      if (id.replace(/\\/g, "/").indexOf(CONFIG.dest.js.cjs) > -1) {
-        delete require.cache[id];
-      }
-    }
-    global.assert = undefined; // https://github.com/angular/angular/issues/1340
-    runSequence('test.unit.cjs/ci', function() {});
+function runNodeJasmineTests() {
+  var doneDeferred = Q.defer();
+  var jasmineProcess = fork('./tools/traceur-jasmine', ['dist/js/cjs/angular2/test/**/*_spec.js'], {
+    stdio: 'inherit'
   });
 
+  jasmineProcess.on('close', function (code) {
+    doneDeferred.resolve();
+  });
+
+  return doneDeferred.promise;
+}
+
+gulp.task('test.unit.cjs/ci', runNodeJasmineTests);
+
+gulp.task('test.unit.cjs', ['build.broccoli.tools'], function (done) {
+  //Run tests once
+  var nodeBroccoliBuilder = getBroccoli().forNodeTree();
+
+
+  nodeBroccoliBuilder.doBuild().then(function() {
+    gulp.start('build/linknodemodules.js.cjs');
+    return runNodeJasmineTests();
+  }).then(function() {
+    //Watcher to transpile file changed
+    gulp.watch('modules/**', function(event) {
+      console.log("fs changes detected", event);
+      nodeBroccoliBuilder.doBuild().then(runNodeJasmineTests);
+    });
+  });
 });
 
 // ------------------
@@ -621,7 +634,7 @@ gulp.task('broccoli.js.cjs', ['build.broccoli.tools'], function() {
 gulp.task('build.js.cjs', function(done) {
   runSequence(
     'broccoli.js.cjs',
-    ['build/linknodemodules.js.cjs'],
+    'build/linknodemodules.js.cjs',
     done
   );
 });