Migrate d3js to v4 and correct d3js visualisations i.e. bug 3.20. Breadcrumb navigation for the language treemap has been improved
import { popularity } from 'app-client/helpers/popularity';
import { module, test } from 'qunit';
module('Unit | Helper | popularity');
// Replace this with your real tests.
test('it works', function(assert) {
let result = popularity([42]);
assert.ok(result);
});