Simple way to load legacy dependency with Webpack for tests

legacy_lib_spec.js

/*
    Example of legacy lib
    ./legacy_lib.js
*/

App = App || {};
App.Tool = function () {
};


/*
    ./legacy_lib_spec.js
*/

// ...

var AppMock = {};

var Tool = require('inject!' +
  'imports?App=AppMock!' +
  'exports?App.Tool!' +
  './legacy_lib'
)({'AppMock': AppMock});

// ...