Running Mocha tests in Webstorm

I'm running Mocha tests for React in Webstorm's terminal window using the following NPM start command:

"tsc && mocha --compilers js:babel-core/register --require ./test_helper.js \"test/**/*.@(js|jsx)\" --watch --watch-extensions js,jsx,tsx"

How do I create a Webstorm Mocha configuration so that I can run tests in Webstorm's test window?

Thanks.