title: How to exclude mock files from Code Coverage Istanbul Reporter
body: <p>I have a question regarding Istanbul Reporter used for reporting my unit testing coverage in my angular 6 application.</p>
  
  <p>My problem is: when the coverage is rendered, I see the mocks in the tested files list and obviously the mocks aren't tested, which gives me wrong coverage stats.</p>
  
  <p>This is my karma.conf file setup by a colleague and I'd like to know if you have any idea on how to exclude those mock files.</p>
  
  <pre><code>module.exports = function (config) {
    config.set({
      basePath: '',
      frameworks: ['jasmine', '@angular-devkit/build-angular'],
      plugins: [
        require('karma-jasmine'),
        require('karma-chrome-launcher'),
        require('karma-jasmine-html-reporter'),
        require('karma-coverage-istanbul-reporter'),
        require('@angular-devkit/build-angular/plugins/karma')
      ],
      client:{
        clearContext: false // leave Jasmine Spec Runner output visible in browser
      },
      coverageIstanbulReporter: {
        dir: require('path').join(__dirname, 'coverage'), reports: [ 'html', 'lcovonly' ],
        fixWebpackSourcePaths: true
      },
      angularCli: {
        environment: 'local'
      },
      reporters: ['progress', 'kjhtml'],
      port: 9876,
      colors: true,
      logLevel: config.LOG_INFO,
      autoWatch: true,
      browsers: ['Chrome'],
      singleRun: false
    });
  };
  </code></pre>
  
  <p>I saw on StackOverflow that it might be done by adding an exclude in the tsconfig.spec.json but even by re-running the code coverage, it still includes them.</p>
  
  <pre><code>{
    "extends": "../../tsconfig.json",
    "compilerOptions": {
      "outDir": "../../out-tsc/spec",
      "module": "commonjs",
      "types": [
        "jasmine",
        "node"
      ],
      "typeRoots": [ "../node_modules/@types" ]
    },
    "files": [
      "src/test.ts",
      "src/polyfills.ts"
    ],
    "include": [
      "**/*.spec.ts",
      "**/*.d.ts"
    ],
    "exclude": [
      "/**/*mock*.ts"
    ]
  }
  </code></pre>
  
  <p>My mock files are inside <strong>tests</strong>/mocks folder in every module/feature and are called "mock-whatevertheymock.ts" </p>
  
  <p>The command to run it is</p>
  
  <pre><code>test:wc-dogs": "ng test --project=wc-dogs--code-coverage
  </code></pre>
  
  <p>Thank you for the help</p>