Cannot read property 'runResult' of undefined in stryker testing framework

I am trying to use this javascript testing framework stryker. When I do stryker run it gives this error. Cannot read property 'runResult' of undefined at: G:\stryker test\node_modules\stryker-mocha-runner.js:30:40

Below is my stryker.conf.js-

module.exports = function(config){
config.set(
  {
 "files": [
{
  "pattern": "src/**/*.js",
  "mutated": true,
  "included": false
},
 "test/**/*.js"
],
 "testRunner": "mocha",
  "reporter": [
    "clear-text",
    "progress"
  ],
 "testFramework": "mocha",
 "coverageAnalysis": "perTest"
}
);
}

My file structure is as follows

---

.stryker-tmp node-modules src index.js test index.js package.json stryker.conf.js