unit test case for plugin directive in vue js

Question

I am trying to write the unit test case for plugin custom directive but not able to understand from where should I start?

 

file - directives.js

 

export default {

install: function(Vue, options) {

// directive to check development env

Vue.directive("development", {

bind(el, binding, vnode) {

debug("directives.development-bind", vnode);

if (!(options.env && options.env.NODE_ENV === "devs")) {

el.innerHTML = "";

} else {

el.classList.add("development");

}

}

});

}

}

 

please suggest to me how to write a unit test using jest?