Grunt Sass to CSS not building

Question

目前，我有app/styles/main.scss，我的sass被分解成多个结构化文件并导入到main.scss中。在我的index.html中，我有以下内容：

<!-- build:css styles/main.css -->
<link rel="stylesheet" href="styles/main.css">
<!-- endbuild -->

我正在使用我在Gruntfile.js中看到的grunt-contrib sass指南针，现在我想另外编译一个文件，即app/styles/modules/_infowindow.scss

我尝试过以下几种方法：

sass: {
  dist: {
    files: [{
      expand: true,
      cwd: '<%= yeoman.app %>/styles/modules',
      src: ['_infowindow.scss'],
      dest: '.tmp/cdn/'
    }]
  }
},

终端输出如下：

Running "sass:dist" (sass) task
Verifying property sass.dist exists in config...OK
Files: app/styles/modules/_infowindow.scss -> .tmp/cdn/_infowindow.css
Options: (none)

但是当我检查.tmp的目录时，没有cdn的目录。

其他：

这是我当前的指南针设置；

// Compiles Sass to CSS and generates necessary files if requested
compass: {
  options: {
    sassDir: '<%= yeoman.app %>/styles',
    cssDir: '.tmp/styles',
    generatedImagesDir: '.tmp/images/generated',
    imagesDir: '<%= yeoman.app %>/images',
    javascriptsDir: '<%= yeoman.app %>/scripts',
    fontsDir: '<%= yeoman.app %>/fonts',
    importPath: './bower_components',
    httpImagesPath: '/images',
    httpGeneratedImagesPath: '/images/generated',
    httpFontsPath: '/fonts',
    relativeAssets: false,
    assetCacheBuster: false,
    raw: 'Sass::Script::Number.precision = 10\n'
  },
  dist: {
    options: {
      generatedImagesDir: '<%= yeoman.dist %>/images/generated'
    }
  },
  server: {
    options: {
      sourcemap: true
    }
  }
}