Solve language display problem in result playlist. problem was in the mirage serializer definition
import { moduleFor, test } from 'ember-qunit';
moduleFor('route:tabs/thematiques', 'Unit | Route | tabs/thematiques', {
// Specify the other units that are required for this test.
// needs: ['controller:foo']
});
test('it exists', function(assert) {
let route = this.subject();
assert.ok(route);
});